Voice, IP, and ATM MPLS Features

This chapter presents the Cisco Voice Interworking Service Module (VISM) set of features and the solutions provided by this voice card, including Voice Over AAL2, Voice over ATM, and Voice over IP (VoIP) networks. This chapter shows you how to add, configure, display, and verify voice connections. It describes VISM clocking, including clocking options and configuration procedures.

Multiprotocol Label Switching (MPLS) is introduced, with the steps required to set up MPLS on the RPM. The MPLS section does not provide detailed configuration information; it is intended only as a guide for planning for MPLS in your network.

The RPM, including memory locations and port numbering, is also described, and the Cisco IOS command-line interface is introduced. Commands for configuring the RPM and for setting up the RPM ATM switch interface are explained. This chapter also discusses permanent virtual circuits (PVCs) on the RPM, including commands for creating and displaying these PVCs.

VISM Overview

The first key topic discussed in this chapter is the Cisco Voice Interworking Service Module (VISM). The VISM consists of a front and back card set designed to operate on the Cisco MGX 8250/8850-PXM1 switches for Releases 1.5 and 2.0. For VISM services on MGX 8230 switches, you must use VISM Release 2.0 or 2.1. The VISM provides interfaces to an ATM packet network and to TDM (time-division multiplexing) T1/E1 lines.

VISM Release 2.1 is a single-height Cisco MGX front card. As many as 24 cards can be installed in a Cisco MGX 8250 or Cisco MGX 8850 shelf, and as many as 8 cards can be installed in a Cisco MGX 8230 shelf. Each VISM supports either eight T1 lines or eight E1 lines. There are two hardware versions of the card—one for T1 lines and one for E1 lines. T1 and E1 lines cannot be mixed on a VISM card. (VISM is not supported on the Cisco MGX 8260 platform.)

A Cisco MGX 8850 Wide Area Edge Switch, when equipped with one or more VISM card sets, can transport digitized voice signals across a packet network. Thus, the VISM/MGX 8850 combination provides an interface or gateway between conventional voice TDM networks and networks based on packet-switching technology.

VISM employs the concept of operating modes, which permit it to be used in a variety of applications. Releases 1.5 and 2.0 have two operating modes—VoIP and AAL2 trunking. These modes support three major applications:

• Switching—Using VoIP mode, this application provides the emulation of many of the functions of a tandem (Class 4) switch. In this application, VISM functions as voice gateway (also called a media gateway) to an IP network and performs call control in conjunction with a call agent. The call agent (also called a media gateway controller) initiates and controls the call control functions. VISM transmits the voice payload through a bearer circuit using VoIP and ATM AAL5 network protocols.

• Multiservice Access with Call Control—This application also uses VoIP mode. In this application, the VISM/MGX 8850 combination is used to concentrate voice and user data services onto a single broadband circuit for transmission over the packet network, again using VoIP and ATM AAL5 techniques. As with the switching application, VISM can function with a call agent to perform call control. In this application, VISM can function as a front-end to a voice gateway.

• AAL2 trunking—This application uses AAL2 trunking mode. In this application, a VISM/MGX 8850 combination is used to concentrate voice (and fax/modem) user services over a preprovisioned AAL2 trunk. VISM merely passes (tunnels) bearer and signaling data across a packet network. It plays no part in call setup and teardown.

VISM architecture provides the following benefits:

• Technology flexibility that allows the incorporation of new or improved technology as it becomes available

• Application flexibility such that it can be used in a range of situations, providing interoperability with a wide variety of equipment types

• Modularity that allows equipment to be purchased and installed as it is needed in a step-by-step manner

Equipped with eight T1 or E1 ports, an array of Digital Signal Processors (DSPs), an HDLC (High-Level Data Link Control) framer, and a broadband interface to the packet network, VISM is ideally suited to processing high-density digital voice circuits providing compression, echo cancellation, dejittering, and packetization on-the-fly.

MPLS Overview

The second key topic discussed in this chapter is Multiprotocol Label Switching (MPLS). MPLS is an improved and efficient method for forwarding packets through a network. One of the most important applications of MPLS is in IP+ATM networks. IP+ATM is Cisco's trade name for equipment that simultaneously supports traditional ATM services (PVCs, SVCs, SPVCs, PVPs, and so on), and optimized IP transport using MPLS.

These networks offer traditional ATM and Frame Relay services while providing optimized IP support using ATM MPLS. MPLS also brings important new services, such as IP Virtual Private Networks (VPNs), to both IP+ATM networks and router networks.

IP-based services, such as IP VPNs and VoIP, are increasingly carried on ATM or Frame Relay networks to meet greater demands. Internet service providers (ISPs) are adding traditional Layer 2 capabilities and services, such as traffic engineering and VPNs, to their IP networks. Cisco addresses this problem with MPLS.

Integrating ATM infrastructures into the Internet model is as simple as providing IP continuity between the ATM network and the rest of the IP world. IP is integrated over ATM inside the autonomous system (AS) using MPLS, and the AS is connected to the rest of the Internet via BGP. This is done using IP+ATM, in which the ATM switches can continue to operate according to the ATM Forum and ITU-T standards while running MPLS in parallel. This means that other network applications such as PNNI, SVC, and AutoRoute can still operate independently of the MPLS application offering routed services.

MPLS is increasingly important as the building of internets on ATM expands and develops across the globe. The Internet is a collection of service providers offering IP services to their customers, all interconnected either directly or via high-speed network access points (NAPs). The NAPs are usually managed by a dedicated provider acting as a point of contact for coordination and connectivity purposes.

Each ISP maintains multiple Points of Presence (PoPs) that serve as concentration points for customer connectivity in multiple regions. PoPs can be interconnected via an ATM infrastructure or via direct high-speed leased-line connections. Currently, ISPs use Border Gateway Protocol version 4 (BGP4) for the purposes of interdomain connectivity. BGP4 offers a wide range of capabilities in segmenting providers' networks and offering routing policies that define the providers' administrative and political boundaries.

RPM Overview

The third key topic discussed in this chapter is the RPM. The RPM is a high-performance router module based on the Cisco 7200 NPE-150 router that has been modified to fit into a 32-slot, full-height MGX 8850 switch. The RPM substantially enhances the MGX 8850 product. The Cisco 7200 NPE-150 router engine can process up to 140 k packets per second (pps). It is a double-height service module that can be placed in any of the MGX 8850 service module slots.

The RPM provides integrated IP in an ATM platform, enabling services such as integrated Point-to-Point (PPP), Frame Relay termination, and IP VPNs using MPLS technology. It provides Cisco IOS-based multiprotocol routing over ATM, Frame Relay and ATM Interface Layer 3 termination, local server interconnect over high-speed LANs, access concentration, and switching between Ethernet LANs and the WAN facilities of the MGX 8850.

The RPM includes interprocessor communication with the main processor switch control module (called the PXM) in the MGX 8850 for management, including configuration, mode supervision (such as redundancy and load-sharing control), and software and configuration file management.

VISM Voice Features

This section provides an overview of the features supported in VISM Releases 1.5, 2.0, and 2.1. VISM firmware releases are not coupled with PXM1 firmware releases, unlike other service modules.

VISM Release 1.5 Features

VISM Release 1.5 is supported on MGX 8250/8850-PXM1 switches. For VISM services on MGX 8230 switches, you must use VISM Release 2.0.

VISM Release 1.5 supports the following voice features:

• Voice over IP (VoIP) using real-time transport protocol (RTP)—VISM Release 1.5 supports standards-based VoIP using RTP (see RFC 1889) and real-time transport control protocol (RTCP) protocols. This allows VISM to interwork with other VoIP gateways.

• Multiservice Access with Call Control—This application also uses VoIP mode. In this application, the VISM/MGX 8850 combination is used to concentrate voice and user data services onto a single broadband circuit for transmission over the packet network using VoIP and ATM AAL5 techniques. VISM can also function with a call agent to perform call control.

• Voice over AAL2 (VoAAL2) with subcell multiplexing PVC—The VISM supports standards-compliant AAL2 adaptation for the transport of voice over an ATM infrastructure. The AAL2 trunking mode is supported.

• Codec support—G.711 Pulse Code Modulation (PCM) A-law and _-law, G.726 Adaptive Differential PCM (ADPCM), and G.729a/b Conjugate Structure Algebraic Code Excited Linear Predictive (CS-CELP) coding.

• Eight T1/E1 lines—The VISM supports eight T1 or eight E1 interfaces when G.711 PCM coding is used. For higher-complexity coders such as G.726-32K and G.729a-8K, the density drops to six T1 or five E1 interfaces and a maximum of 145 connections.

• Echo cancellation—The VISM provides on-board echo cancellation on a per-connection basis. Up to 128 milliseconds of user-configurable near-end delay can be canceled. Echo cancellation is compliant with ITU G.165 and G.168 specifications.

• Voice Activity Detection (VAD)—VISM uses VAD to distinguish between silence and voice on an active connection. VAD reduces a voice connection's bandwidth requirements by not generating traffic during periods of silence in an active voice connection. At the far end, comfort noise is generated.

• Fax/modem detection for echo cancellation and VAD control—The VISM continually monitors and detects fax and modem carrier tones. When carrier tone from a fax or modem is detected, the connection is upgraded to full PCM to ensure transparent connectivity. Fax and modem tone detection ensures compatibility with all voice-grade data connections.

• Channel Associated Signaling (CAS) tunneling via AAL2 (for AAL2 trunking mode)—The VISM in AAL2 mode facilitates transport of CAS signaling information. CAS signaling information is carried transparently across the AAL2 connection using Type 3 packets. In this mode, VISM does not interpret any of the signaling information.

• Primary Rate Interface (PRI) tunneling via AAL5 (for AAL2 trunking mode)—VISM supports transport of D-channel signaling information over an AAL5 VC. The signaling channel is transparently carried over the AAL5 VC and is delivered to the far end. In this mode, VISM does not interpret any of the signaling messages.

• Voice connection admission control (CAC)—VISM can be configured to administer CAC so that the bandwidth distribution between voice and data can be controlled in AAL2 mode.

• Type 3 Packet for dual tone multifrequency (DTMF)—The VISM in AAL2 mode facilitates transport of DTMF signaling information. DTMF information is carried transparently across the AAL2 connection using Type 3 packets.

• Dual (redundant) PVCs for bearer/control—The VISM can configure two PVCs for bearer/signaling traffic terminating on two external routers (dual-homing). VISM continually monitors the status of the active PVC by using OAM loopback cells. Upon detection of failure, the traffic is automatically switched over to the backup PVC.

• 64 kbps clear channel transport—The VISM supports 64 kbps clear-channel support. In this mode, all codecs are disabled, and the data is transparently transported through the VISM.

• DTMF relay for G.729—In VoIP mode, DTMF signaling information is transported across the connection using RTP named signaling event (NSE) packets.

• Media Gateway Control Protocol (MGCP) Version 0.1 for VoIP with Softswitch control—VISM supports MGCP Version 0.1. This open protocol allows any Softswitch to interwork with the VISM module.

• Support for call agent Simple Gateway Control Protocol (SGCP) version 1.0, SGCP 1.1+

• Resource Coordination via Simple Resource Control Protocol (SRCP)—SRCP provides a heartbeat mechanism between the VISM and the Softswitch. In addition, SRCP also provides the Softswitch with gateway auditing capabilities.

• Courtesy downing of ongoing voice calls when the VISM is taken out of service for maintenance or other reasons

• Support for CCS (Common Channel Signaling) transport across an AAL5 trunk

• Support for full continuity testing (COT)—Supports origination and terminating loopback and transponder COT toward the packet bearer and the TDM sides.

• 1:N cold redundancy using SRM-3T3 capabilities (bulk mode support for T1 lines only)—Calls do not persist during switchover.

VISM Release 2.0 Features

VISM Release 2.0 supports the VISM Release 1.5 features just listed, in addition to the features listed in this section. VISM Release 2.0 is supported on MGX 8230, 8250, and 8850-PXM1 switches.

Here are the key features of the VISM Release 2.0 card set:

• PRI backhaul to the Softswitch using Reliable User Data Protocol (RUDP)—The PRI backhaul capability provides PRI termination on the VISM with the Softswitch providing call control. ISDN Layer 2 is terminated on the VISM, and Layer 3 messages are transported to the Softswitch using RUDP.

• Codecs preference—VISM provides the capability to have the codecs negotiated between a call's two endpoints. The VISM can be configured, for a given endpoint, to have a prioritized list of codecs. Codec negotiation can be directly between the endpoints or can be controlled by a Softswitch.

• 31 timeslots for E1 with 240 channels only—Although all 31 timeslots on an E1 port can be used, there is a limitation of 240 connections per card.

VISM Release 2.1 Features

VISM Release 2.1 supports the VISM Release 1.5 and 2.0 features listed previously. It also includes voice compression to G.711, G.726-16k, 24k, 32k, 40k, G.729a, and G.729ab standards.

VISM offers different solutions for carrying voice traffic, including Voice Over AAL2 network, VoIP network, and Voice Over ATM services, as described in the following sections. An introductory discussion of voice connections is presented first.

Voice Connections

A voice connection is an end-to-end permanent virtual circuit (PVC) that originates and terminates on MGX VISM endpoints. The connection receives PCM voice samples and signaling and converts them into ATM cells using AAL2 (voice traffic and CAS signaling) or AAL5 (CCS signaling) and transports the cells to the remote endpoint. All voice connections are bidirectional, meaning that traffic flows in both directions.

A single AAL2 voice connection can carry multiple voice calls. This is called AAL2 multiplexing. The channel identifier (CID) differentiates voice traffic streams on the connection.

You can add two types of voice connections in an MGX network: feeder and local. Feeder connections go from the VISM to the PXM trunk and are transported through the ATM backbone network (BPX or other) to the destination MGX switch. Local connections go from one endpoint on an MGX switch to another endpoint on the same switch. Local connections can be between endpoints on the same or different VISM cards. Feeder and local connections perform the same functions.

Endpoints

All VISM connections terminate on endpoints. An endpoint is a channel (DS0 or timeslot) on a T1 or E1 line. An endpoint is defined by its endpoint number and the T1 or E1 line and channel number. You must create VISM endpoints before you can terminate connections on them.

Channel Identifiers

A CID identifies a specific voice traffic stream. You use it when multiplexing multiple voice calls across a single ATM connection. On the MGX switch, the CID also links the connection to the endpoint. When you create a CID, you identify the compression type and other voice processing characteristics, such as echo cancellation and dual-tone multifrequency (DTMF) transport. Figure 22-1 shows the VISM with endpoints, connection, and CIDs.

Figure 22-1 Channel Identifiers

Feeder Example

A voice feeder connection has three connection segments:

• A master connection between the VISM endpoint and PXM1 trunk on one MGX switch.

• A routing connection through the ATM backbone network. The routing connection should be rt-VBR for voice traffic and nrt-VBR for signaling traffic.

• A master connection between the VISM and PXM1 trunk on the other MGX switch.

Figure 22-2 shows a voice feeder connection in an MGX network.

Local Example

An ATM local connection has two connection segments:

• A slave connection on one VISM. The slave connection must be added first.

• A master connection on the other VISM pointing to the slave connection.

Figure 22-2 Feeder Example

How PCM Samples Are Converted into ATM Cells

How are ATM cells created on Voice over AAL2 (VoAAL2) services on the VISM?

Figure 22-3 shows a high-level view of the traffic flow of voice traffic on the VISM.

Figure 22-3 Traffic Flow

Pulse Code Modulation (PCM) voice samples come in from the line and are processed by echo cancellation digital signal processors (DSPs) to eliminate any echo (if echo cancellation is enabled). Next, the PCM samples are processed by the compression DSPs. This is where the 8-bit PCM samples are converted into a variety of different samples (length and frequency), depending on the compression method in use. The compressed samples go to the segmentation and reassembly (SAR) processor to be loaded into ATM cells for transport to the cell bus and across the network.

AAL2 Segmentation

ITU-T Recommendation I.363.2 specifies the basic AAL2 structure for VoAAL2. Figure 22-4 shows three voice samples (from the same or different voice calls) and how they are made into an ATM cell.

Figure 22-4 Voice Sample Conversion to ATM Cell

Table 22-1 describes each stage of the AAL2 segmentation process.

Table 22-1 AAL2 Segmentation Process

AAL2 Coding

Here are the coding or compression methods supported on the VISM:

• G.711u—PCM with µ-law coding

• G.711a—PCM with A-law coding

• G.726—ADPCM

• G.729—CS-CELP with 10-, 20-, and 30-millisecond (ms) cell times

The coding type you use affects the voice sample size and the sample and cell frequency. Ultimately, this determines how much bandwidth the voice traffic utilizes. Figure 22-5 shows each coding type and the ATM cell created from the voice samples, assuming that multiplexing (multiple voice streams on the same ATM connection) is not in use.

Figure 22-5 AAL2 Coding Types

Voice Over AAL2 Network

The Voice over AAL2 (VoAAL2) solution with VISM is used to replace trunk lines between voice switches. A separate PVC is needed for voice channels destined for a specific remote endpoint. Signaling information is sent using one of two methods: CAS signaling is sent with voice traffic, and CCS signaling is sent on a separate AAL5 connection. Except for signaling extraction and insertion, the VISM does not participate in the signaling process.

• As described with the previous VISM features, the VISM supports standards-compliant AAL2 adaptation for the transport of voice over an ATM infrastructure with AAL2 trunking mode.

Here are the major features of AAL2 trunking mode:

• The voice payload is transported across the packet network using an AAL2 PVC. Multiple voice channels are supported in a single PVC using CIDs (channel identifiers) and subcell multiplexing. A single VISM supports up to 64 AAL2 PVCs.

• Call setup through a call agent is not supported. All bearer paths are provisioned using either the command-line interface (CLI) or Simple Network Management Protocol (SNMP).

• If CAS signaling is used, the signaling is transported across the packet network along with the voice payload using AAL2 Type 3 packets.

• CCS signaling channels are supported and are transported across the packet network using a separate AAL5 PVC.

In AAL2 trunking mode, VISM provides a set of AAL2 trunks carrying the voice payload over the packet network. Figure 22-6 shows a high-level view of VoAAL2 between two voice switches.

Figure 22-6 VoAAL2 with VISM

Voice payloads and CAS signaling are transported across the AAL2 trunk. If a channel is configured for CCS signaling, the signaling is transmitted by extracting HDLC frames and forwarding them over preprovisioned AAL 5 virtual circuits (the voice payload is still transmitted using AAL 2).

In this role, the VISM merely passes signal traffic to and from the trunk.

VoIP Network

The VoIP solution with VISM requires one or more (up to eight) call agents to manage signaling for the voice calls. The Cisco Virtual Switch Controller (VSC) is one such call agent. Other call agents might be supported. The call agent receives call requests and other signaling messages from the voice switch and converts these to Simple Gateway Control Protocol (SGCP) or MGCP and sends them to the VISM. The VISM uses the signaling messages to set up or break down voice calls. Multiple call agents communicate with each other using Enhanced ISDN User Part (E-ISUP).

Here are the major features of VoIP mode:

• Calls are set up under the control of one or more (up to eight) call agents using SGCP or MGCP protocol (CLI-configurable).

• CAS signaling can be extracted from the voice payload and backhauled to the call agent using either SGCP or MGCP.

• CCS signaling on an ISDN D-channel can be backhauled as Q.931 to the call agent using RUDP protocol.

• The voice payload is converted to IP packets, which are then tunneled through an AAL5 PVC to the IP network.

• A single PVC for both signaling and data can be configured with a second (redundant) channel together with automatic switchover in the event of a failure. Alternatively, AAL5 PVCs can be configured to provide a split into control and bearer streams, each on a separate PVC. If the signal and data streams are split, one of the PVCs (but not both) can be provided with a second redundant PVC.

• In VoIP mode, VISM operates in conjunction with a call agent.

Briefly, the call setup procedure consists of the following steps:

In VoIP mode, a single AAL5 PVC is set up for communication with the packet-switching network. All calls use this single PVC. It is the responsibility of the network edge router to extract the IP addresses from the voice payloads and route the traffic across the IP network.

Figure 22-7 VoIP Network

The network connecting VISMs is IP. This can be an IP-only network (for example, Cisco 7500 series routers) or an IP+ATM network (for example, MGX RPMs with an ATM backbone network). The VISMs have PVCs between them to carry control and voice (bearer) traffic. These PVCs use AAL5 for segmentation and reassembly (SAR) of the IP packets to ATM. Figure 22-7 shows a high-level view of a VoIP network using VISM. You can use the same PVC or separate PVCs for control and voice traffic.

Voice Over ATM Services on the VISM

A Cisco MGX 8850 Wide-Area Edge Switch, when equipped with one or more VISM cards, can transport digitized voice signals across a packet network while providing voice quality and reliability equal to the quality expected on the public telephone network. By transporting the voice traffic over ATM packet networks instead of traditional time-division multiplexing (TDM) networks, you realize considerable savings in network bandwidth requirements. Thus, the VISM/MGX 8850 combination provides an interface or voice gateway between conventional voice TDM networks and networks based on packet-switching technology.

The MGX network supports VISM-to-ATM connections. The primary use of this type of connection is to provide interworking with Cisco 3810 voice services.

Figure 22-8 shows an example of VISM and 3810 voice interworking.

Figure 22-8 VISM and Voice Interworking

Follow these steps to create Voice over ATM (VoATM) services in the MGX network on VISM:

You have completed the steps necessary to create Voice over ATM (VoATM) services in the MGX network on VISM.

Digital Signal Processors

A major feature of VISM is the array of Digital Signal Processors (DSPs) that provide extensive voice signal processing capability.

Each VISM contains 37 DSPs. Twelve are general-purpose and can be configured to perform echo cancellation or data compression. Twenty-four can be used for data compression only. One DSP is a Jukebox DSP that is used to load code (program) overlays to the other 36 DSPs.

In addition to the DSPs, one HDLC controller is used for CCS signal processing.

Together, the DSPs support the DS0 channels of the eight T1/E1 lines.

A timeslot interchanger routes the DS0s to

• A data compression DSP or

• An echo cancellation DSP and then a data compression DSP or

• The HDLC controller (for CCS processing)

DSPs are loaded with their programs at boot time.

VISM Clocking

This section describes the options and procedures for setting up the clocking on a VISM-equipped MGX 8850 shelf.

VISM Clocking Options

VISM cards and MGX 8850 PXM cards each provide multiple clocking options. To avoid conflicts and to ensure proper operation, it is important that the settings for clocking options in both card types be considered together.

An overriding principle is that an MGX 8850 shelf consisting of PXM and VISM cards should have one and only one primary clocking source.

A second principle is that at the VISM/MGX 8850 PXM interface there are two options:

• The MGX 8850 PXM card provides clock for all the VISM cards in the shelf.

• One of the VISM cards on the shelf provides clock for the PXM (and hence the remainder of the shelf).

The user must choose one of these options.

Using the first option, in which the clock source originates at the PXM side of the VISM/PXM interface, the source stems from one of the following:

• An external BITS clock on the PXM's T1 or E1 backcard port

• An external OC3 signal on a PXM SONET backcard port

• The PXM's internal crystal

The internal crystal is the default and is automatically set as the primary clock source at power-on. The user can use one of the other two clock sources by executing the cnfclksrc (configure clock source) command.

Also, in this situation, the PXM becomes the clock source for the entire shelf. As such, it uses its clock source to provide clocking for all the VISM cards in the shelf. The VISM cards, in turn, use this clock to provide clocking for their T1 or E1 lines. In order for this situation to operate correctly, all the VISM lines must be configured for local clocking using the cnfln (configure line) command.

Moving on to the second option, the clock source originates on the VISM side of the VISM/PXM interface. It stems from one of the T1 or E1 lines on one of the VISM cards (the line receiving the clock signal on the selected VISM card must be line number 1). The line number 1 that is receiving the clock source must be configured for loop clocking using the cnfln command. All the remaining T1 or E1 lines on all the VISM cards in the shelf must be configured for local clocking.

Also, in this situation, the VISM becomes the clock source for the PXM and hence the entire shelf, including the remaining VISM cards. In order for this situation to operate correctly, the PXM must be configured for a service module as the clocking source with the selected VISM and its clock line specified in the cnfclksrc command.

Configuration Procedures

Follow these steps to set up clocking on a VISM-equipped MGX 8850 shelf:

cnfclksrc <slot.port> <clktype>

cnfln <line_num> <line_code> <line_len> <clk_src>
  <line_type> <loopback_detection>

You have successfully set up clocking on a VISM-equipped MGX 8850 shelf.

Commands for Adding, Configuring, and Displaying Voice Connections

This section describes the commands you use to add, configure, and display voice connections on the VISM:

• dspvismparam—Displays the VISM configuration, including the voice mode (VoIP or VoAAL2).

• cnfvismmode—Changes the VISM configuration, including the voice mode.

• addport—Creates a logical port on the VISM. This command must be used only once on the VISM.

• delport—Removes the logical port from the VISM.

• dspport—Lists the logical port on the VISM.

• addrscprtn—Creates a resource partition. This command must be used only once on the VISM.

• delrscprtn—Removes a resource partition.

• dsprscprtn—Displays the resource partition configuration.

• cnflnsig—Changes a line's signaling type.

• dsplndsp—Displays the line digital signal processor (DSP) configuration, including echo cancellation and voice activity detection (VAD).

• cnfecanenable—Enables or disables a line's echo cancellation.

• cnfecanrec—Sets a line's residual echo control.

• cnfecantail—Sets the maximum echo cancellation tail length between 24 and 128 milliseconds.

• cnfcompvad—Enables VAD on a line.

• addendpt—Creates an endpoint on the VISM.

• delendpt—Removes an endpoint from the VISM.

• addendpts—Adds multiple, contiguous endpoints on the VISM.

• delendpts—Removes multiple, contiguous endpoints from the VISM.

• dspendpts—Lists all endpoints on the VISM.

• dspendpt—Lists detailed information for an endpoint.

• addcon—Creates a new voice connection on the VISM.

• delcon—Removes a voice connection from the VISM.

• dspcons—Lists summary status and configuration information for all connections on the VISM.

• dspcon—Lists detailed configuration information for a connection.

• addcid—Creates a new CID on the VISM that associates a connection with an endpoint.

• delcid—Removes a CID from the VISM and disassociates a connection with an endpoint.

• dspcids—Lists configuration information for all CIDs on a connection.

• dspcid—Lists configuration information for a CID.

Display VISM Parameter Command

The dspvismparam command shows the voice mode configuration for the VISM. Use this command to learn whether the VISM is configured for VoIP or VoAAL2 services. You can change the VISM's voice mode using the cnfvismmode command. Example 22-1 shows the dspvismparam output.

Example 22-1 dspvismparam Output

smoke.1.3.VISM8.a > dspvismparam
VISM mode:                  aal2Trunking
CAC flag:                   enable
DS0s available:             240
Template number:            2
Percent of functional DSPs: 100
IP address:                 0.0.0.0
Subnet mask                 0.0.0.0
RTCP report interval:       1000
RTP receive timer:          disable
ControlPrecedence/Tos:      0x60
BearerPrecedence/Tos:       0xa0
Aal2 muxing status:         disable
Tftp Server Dn              TFTPDOMIAN

The information shown in the dspvismparam output includes the following:

• VISM mode—Either AAL2 trunking or VoIP switching.

• Connection Admission Control (CAC) flag—Specifies whether CAC is enabled or disabled on the VISM. This field applies only to VoIP mode.

• DS0s available—The number of channels available on the card. This number depends on the card type (T1 or E1) and the template in use. This field applies only to VoAAL2 mode.

• Template number—Specifies which template (1 or 2) is configured for the VISM. Template number 1 supports G.711u, G.711a, G.729a, G.729ab, G.726/32, and clear-channel codecs. Template 1 is not allowed in VoIP mode and reduces the number of channels supported on the card. Template number 2 supports G.711u, G.711a, and clear channel only. You can change the template using the cnfcodectmpl command.

  NOTE

  Template number 1 in VISM Release 2.1 supports G.711u, G.711a, G.729a, G.729ab, G.726/32, and clear-channel codecs, plus G.726 16K, 24K, 32K, and 40K codecs.

• Percent of functional DSPs—The percentage of DSPs that are fully functional on the VISM.

• IP address—The IP address of the VISM used in VoIP mode.

• Subnet mask—The subnet mask that the VISM uses in VoIP mode.

• Real-time Transport Control Protocol (RTCP) report interval—The amount of time between RTCP messages for VoIP.

• Real-time Transport Protocol (RTP) receive timer—The amount of time between expected RTP messages.

• Control precedence—Control precedence for IP packets is a type of service (ToS) that conforms to RFC 1349. It determines which IP packets have higher priority as defined by the bearer precedence.

• Bearer precedence—Bearer precedence for IP packets conforms to RFC 791. It can be in the priority range of 0 to 7. You can adjust the precedence of the bearer IP packets as follows: 0 = low priority, 7 = high priority. The priority levels help ensure timely delivery of all traffic in a heterogeneous network.

• AAL2 multiplexing status—Specifies whether multiple voice streams can be multiplexed onto the same AAL2 connection. You can change this field using the cnfaal2subcellmuxing command.

• TFTP server domain name—The domain name of the TFTP server.

Configure VISM Mode Command

The cnfvismmode command changes the VISM card's voice mode. Use this command if you need to change the VISM to or from VoIP or VoAAL2.

Here is the cnfvismmode command syntax:

cnfvismmode <mode>

mode is either 1 for VoIP or 2 for VoAAL2.

For example, type cnfvismmode 2 to change the mode from VoIP to VoAAL2.

Add Port Command

The addport command creates a logical interface between the VISM and the PXM1. You must type this command before you add any endpoints, connections, or CIDs on the VISM. This command has no required or optional parameters.

Display Port Command

The dspport command shows the VISM port status. Use this command to verify that the port was added. You can delete the port using the delport command.

Example 22-2 shows the dspport output.

Example 22-2 dspport Output

smoke.1.3.VISM8.a > dspport
  vismPortNum:           1
  vismPortRowStatus:     add
  vismPortSpeed:         60000
  vismPortState:         active

The information shown in the dspport output includes the following:

• Port number—Always 1.

• Port row status—The row status is add unless the port is modified. In that case, the status is mod.

• Port speed—Indicates the amount of voice traffic that the VISM can send to the PXM1.

• Port state—In most cases, the port state is active.

Add Resource Partition Command

The addrscprtn command creates resource partitions on the VISM port. You must issue this command after adding the port and before you add any endpoints, connections, or CIDs to the VISM. You can remove the resource partition using the delrscprtn command.

Here is the addrscprtn command syntax:

addrscprtn <controller ID>

controller ID is 1 for Portable AutoRoute (PAR).

For example, type addrscprtn 1 to add the PAR resource partition to the VISM port.

Display Resource Partition Command

The dsprscprtn command shows the resource partition configuration. Note that the resource partition cannot be configured. Example 22-3 shows the dsprscprtn output.

Example 22-3 dsprscprtn Output

smoke.1.1.VISM8.a > dsprscprtn
  vismResPartPortNum:        1
  vismResPartCtrlrNum:       par
  vismResPartRowStatus:      add
  vismResPartNumOfLcnAvail:  72
  vismResPartLcnLow:         131
  vismResPartLcnHigh:        510
  vismResPartIngrPctBW:      100
  vismResPartEgrPctBW:       100
  vismResPartCtrlrID:        1

The information shown in the dsprscprtn output includes the following:

• Port number—Always 1.

• Controller number—Always par.

• Row status—Always add.

• Number of logical connection numbers (LCNs) available—The number of channels that you can add on the VISM.

• LCN low—The minimum LCN or channel number allowed.

• LCN high—The maximum LCN or channel number allowed.

• Ingress percent bandwidth—The percentage of the ingress port bandwidth allocated to this resource partition.

• Egress percent bandwidth—The percentage of the egress port bandwidth allocated to this resource partition.

• Controller ID—Always 1 for PAR.

Configure Line Signaling Command

The cnflnsig command sets the signaling method of a T1 or E1 line. Use this command to enable CAS or CCS signaling on the line. Even if the physical line is set for CCS using the cnfln command, you must use the cnflnsig command to set up the signaling method. Use the dspln command to learn the line-signaling configuration.

Here is the cnflnsig command syntax:

cnflnsig <line number> <signaling type>

The parameter options are as follows:

• line number—The T1 or E1 line number. 1 to 8.

• signaling type—The voice signaling type. 1 = CAS, 2 = CCS, 3 = no signaling.

For example, type cnflnsig 2 1 to enable CAS signaling on line number 2.

Display Line DSP Command

The dsplndsp command shows the DSP configuration for a line. Use this command to learn the echo cancellation and VAD settings. Example 22-4 shows the dsplndsp output.

Example 22-4 dsplndsp Output

smoke.1.1.VISM8.a > dsplndsp 8
 VismLineNum:      8
 ECANEnable:       enable
 MaximumTail:      32 milliseconds
 ResidualEcho:     SuppressResidual
 VoiceDetection:   Enable

The information shown in the dsplndsp output includes the following:

• VismLineNum—Represents the VISM card line number.

• Echo cancel enable—Enabled or disabled. Use the cnfecanenable command to change this field.

• Maximum tail—The maximum tail length (delay) for the echo canceller. Choices include 24, 32, 48, 64, 80, 96, 112, and 128 milliseconds. Use the cnfecantail command to change this field.

• Residual echo—The echo canceller's action for residual echo. Residual echo is what is left over after the echo is cancelled due to the echo model's being imperfect. Choices include cancel only, suppress residual, or inject comfort noise. Use the cnfecanrec command to change this field.

• Voice detection—Specifies whether VAD is enabled or disabled. Use the cnfcompvad command to change this field.

Add Endpoint and Add Endpoints Commands

The addendpt and addendpts commands are used to add new endpoints on the VISM. The addendpt command creates one endpoint, and the addendpts command creates multiple contiguous endpoints. It is recommended that you use the addendpts command to create endpoints on all available channels when you start configuring your VISM. You must add endpoints before adding connections and CIDs to the VISM. Use the delendpt and delendpts commands to delete endpoints on the VISM.

Here is the addendpt command syntax:

addendpt <endpoint number> <DS1 number> <DS0 number>

Here is the addendpts command syntax:

addendpts <endpoint number> <DS1 number> <DS0 number> <number of endpoints>

The parameter options are as follows:

• endpoint number—Used when you add a CID. 1 to 192 for T1, 1 to 240 for E1.

• DS1 number—The T1 or E1 line number. 1 to 8.

• DS0 number—The DS0 or (starting) timeslot number. 1 to 24 for T1, 1 to 31 for non-CAS E1, 1 to 15 and 17 to 31 for CAS E1.

• number of endpoints (addendpts only)—The number of contiguous endpoints you want to add. 1 to 192 for T1, 1 to 240 for E1.

For example, type addendpt 1 4 8 to add endpoint 1 to timeslot 8 on line 4; type addendpts 2 4 9 10 to add 10 endpoints starting with endpoint number 2 on timeslot 9 on line 4.

Display Endpoints Command

The dspendpts command lists all the endpoints configured on the VISM. Use this command to learn which endpoints exist. Example 22-5 shows the dspendpts output.

Example 22-5 dspendpts Output

smoke.1.3.VISM8.a > dspendpts
  EndptNum Ena/Speed
  -------- --- -----
  1        act/ 64k
  2        act/ 64k
  3        act/ 64k
  4        act/ 64k
  5        act/ 64k
  6        act/ 64k
  7        act/ 64k
  8        act/ 64k
  9        act/ 64k
  10       act/ 64k
  11       act/ 64k
  12       act/ 64k
  13       act/ 64k
  14       act/ 64k
  15       act/ 64k
  16       act/ 64k
  17       act/ 64k
  18       act/ 64k
  19       act/ 64k
  20       act/ 64k
Type <CR> to continue, Q<CR> to stop:

Display Endpoint Command

The dspendpt command shows detailed information about an endpoint. Use this command to learn which line and timeslot an endpoint is associated with. Example 22-6 shows the dspendpt output.

Example 22-6 dspendpt Output

smoke.1.1.VISM8.a > dspendpt 1
  EndptNum:        1
  EndptLineNum:    8
  EndptName:       E1-8/1@cisco.com
  EndptSpeed:      64 kbps
  EndptState:      active
  EndptChannelMap: 2
  EndptEnable:     active
  EndptLoopback:   disabled

The dspendpt output includes the following information:

• EndptNum—The endpoint number.

• EndptLineNum—The line an endpoint is associated with.

• EndptName—The endpoint name in the form line type-line number/endpoint number@domain name. line type is T1 or E1, and domain name is the VISM domain name that is used for VoIP signaling messages. The default domain name is cisco.com. In Example 22-6, E1-8/1@cisco.com is endpoint 1 on E1 line 8.

• EndptSpeed—The endpoint speed. Either 56 or 64 kbps.

• EndptState—The endpoint state, usually active.

• EndptChannel Map—A hexadecimal number representing the timeslot assigned to the endpoint. If you convert this number into a binary number, each bit represents a timeslot. The least-significant digit (on the right) is timeslot 1; the most-significant digit (on the left) is the highest timeslot number. Notice that leading zeros are not shown. In Example 22-6, the channel map is 2, which is a binary 10. This means that timeslot 1 is assigned to this endpoint. (Because this is an E1, timeslot 0, the least-significant bit is reserved for framing.)

• EndptEnable—Usually active.

• EndptLoopback—The endpoint loopback state, either enabled or disabled. You can loop the endpoint using the addendptloop command and remove an endpoint using the delendptloop command.

Add Connection Command

The addcon command is used to create a new voice connection on the VISM. You can use the delcon command to remove the connection.

Here is the addcon command syntax:

addcon <local VCI> <preference> <PVC type> <application> <PCR> <mastership>
  [remote connection ID]

The parameter options are as follows:

• local VCI—The LCN number. You use this number when you configure a CID. 131 to 510.

• preference—Specifies a primary or secondary channel for redundancy purposes. 1 = primary, 2 = secondary.

• PVC type—1 = AAL5 used for VoIP and signaling channels, 2 = AAL2 for VoAAL2 channels, 3 = AAL1 (not supported).

• application—Specifies how the connection is used. 1 = control for VoIP when a separate control channel is used, 2 = bearer for voice traffic, 3 = signaling for VoAAL2.

• PCR—The connection's Peak Cell Rate (PCR). For connections in which multiple voice circuits are multiplexed onto one connection, you need to calculate the PCR based on the aggregate rate of the supported voice calls. 1 to 75,600 cells per second (cps) for AAL5 bearer PVC, 1 to 24,400 cps for AAL5 control PVC, 1 to 50,000 cps for T1 AAL2 bearer PVC, 1 to 60,000 cps for E1 AAL2 bearer PVC, 1 to 400 cps for signaling PVC in AAL2 trunking mode.

• mastership—1 = master, 2 = slave. If you are adding a slave connection, you do not need to specify the mastership or the remote connection ID.

• remote connection ID—The destination connection ID for master connections in the form node name.card slot.port.VPI.VCI. If you are adding a feeder connection to the PXM1, card slot must be 0. If you are adding a local connection to another VISM, port is always 1, VPI is always 0, and VCI is the remote LCN. If you are adding a local connection to an ATM interface, you must specify the port, VPI, and VCI on the ATM side.

Display Connections Command

The dspcons command lists summary status information for all connections on the VISM. Example 22-7 shows the dspcons output.

Example 22-7 dspcons Output

smoke.1.3.VISM8.a > dspcons
 ConnId      ChanNum Status Preference Protection  Active Locking
 -------     ------- ------ ---------- ---------- ------- --------
smoke.3.1.0.131   131  Mod           1 unprotected unknown unlock
smoke.3.1.0.132   132  Add           1 unprotected unknown unlock
smoke.3.1.0.133   133  Add           1 unprotected unknown unlock

The dspcons output includes the following information:

• Connection ID—The local connection ID in the form node name.card slot.1.0.LCN

• Channel number—The local VCI or LCN

• Status—Add or Mod (modify)

• Preference—Specifies a primary (1) or secondary (2) channel

• Protection—The redundancy protection type

• Active—The redundancy state

• Locking—The redundancy locking

Display Connection Command

The dspcon command shows detailed configuration information for a connection. Example 22-8 shows the dspcon output. There are two pages to the dspcon output; the second page is shown in Example 22-9.

Example 22-8 dspcon Output, Page 1

smoke.1.3.VISM8.a > dspcon 131
 ChanNum:         131
 ChanRowStatus:      Mod
 ChanLocalRemoteLpbkState: Disabled
 ChanTestType:       TestOff
 ChanTestState:      NotInProgress
 ChanRTDresult:      65535 ms
 ChanPortNum:       1
 ChanPvcType:       AAL2
 ChanConnectionType:    PVC
 ChanLocalVpi:       0
 ChanLocalVci:       131
 ChanLocalNSAP:      736d6f6b65000000000000000000000003000100
 ChanRemoteVpi:      0
 ChanRemoteVci:      131
 ChanRemoteNSAP:      736d6f6b65000000000000000000000001000100
 ChanMastership:      Master
 ChanVpcFlag:       Vcc
 ChanConnServiceType:   CBR
 ChanRoutingPriority:   1
 ChanMaxCost:       4294967295
 ChanRestrictTrunkType:  No Restriction
Type <CR> to continue, Q<CR> to stop:

Many of the fields listed in the dspcon output can be modified using a number of configuration commands discussed in this section. Other information in the dspcon output includes the following:

• RTD result—The result of the most recent round-trip delay test (use the tstdelay command). If the test has never been run, it reports 65,535 milliseconds.

• Channel local NSAP—The network service access point (NSAP) address uniquely identifies this interface (port) in the network. The 20-byte hexadecimal address has the following fields:

  • The most-significant 8 bytes (16 digits) spell out the node name in ASCII. The connection in Example 22-8 is on node smoke.

  • The card slot number is the fourth byte from the right. The connection in Example 22-8 is on card 3.

  • The port number is the second byte from the right. All VISM connections are on port 1.

Example 22-9 shows the second page of the dspcon output.

Example 22-9 dspcon Output, Page 2

ChanConnPCR:       100
 ChanConnPercentUtil:   100
 ChanPreference:      1
 ChanRemotePCR:      100
 ChanRemotePercentUtil:  100
 ChanProtection:      unprotected
 ChanActivityState:    unknown
 ChanLockingState:     unlock
 ChanApplication:     bearerf
 ChanServiceType:     cbr
 ChanScrIngress:      100
 ChanMbsIngress:      100
 ChanNumNextAvailable: 132

Add CID Command

The addcid command creates a new CID that associates a connection with an endpoint. You can add multiple CIDs to a connection, but each must have a different endpoint and CID. Use the delcid command to delete a CID from the VISM.

Here is the addcid command syntax:

addcid <endpoint number> <LCN> <CID number> <codec type> [profile type]
  [profile number] [VAD] [VAD initialization timer] [echo cancellation]
  [triple redundancy protection] [CAS transport] [DTMF transport] [ICS]
  [packet period]

The parameter options are as follows:

• endpoint number—The endpoint associated with this CID. Only one CID can be associated with an endpoint. 1 to 192 for T1 cards, 1 to 240 for E1 cards.

• LCN—The logical connection number. 131 to 510.

• CID number—The CID must be unique per connection (LCN). 9 to 255.

• codec type—The voice compression type. 1 = G.711u, 2 = G.711a, 3 = G.726/32, 4 = G.729a, 5 = G.729ab, 6 = clear channel. (VAD must be off when the codec is clear-channel.)

• profile type—1 = ITU, 3 = custom. This parameter is required if codec type is G.729a/ab.

• profile number—1, 2, or 7 for ITU. 100 or 101 for custom. Use the dspaal2profile command to see the profile characteristics. Be sure to use a profile that supports the compression type (codec type) you are using. This parameter is required if codec type is G.729a/ab.

• VAD—Enables or disables VAD. 1 = VAD on, 2 = VAD off (the default).

• VAD initialization timer—Determines how long to wait after a speech burst before starting VAD. If this time is too short, you might experience clipping. If it is too long, you might not get the bandwidth savings you require. 250 to 65,535 milliseconds.

• echo cancellation—Enables or disables echo cancellation. 1 = on (default), 2 = off.

• triple redundancy protection—Enables or disables triple redundancy protection. 1 = on, 2 = off.

• CAS transport—Enables or disables the transport of CAS signaling bits in the AAL2 traffic stream. 1 = on (default), 2 = off.

• DTMF transport—Enables or disables the transport of DTMF tones in the AAL2 traffic stream (inband). 1 = on (default), 2 = off.

• Integrated Communications System (ICS)—1 = enable, 2 = disable.

• packet period—The amount of time between G.729a packets. 10, 20, 30, or 40 milliseconds.

For example, type 1131 9 1 1 1 1 300 1 2 1 1 1 to create CID number 9 associated with endpoint 1 and LCN 131. This CID is set for G.711u and uses ITU profile number 1.

Display CIDs Command

The dspcids command lists all the CIDs on a specified LCN. Use this command to learn which CIDs are on a connection and how they are configured. Example 22-10 shows the dspcids command output.

Example 22-10 dspcids Output

smoke.1.1.VISM8.a > dspcids 132
LCN CID Endpt Cid  Type3   VAD  Prof  Prof Codec Cas DTMF   ICS  Pkt
Num Num  Num  Status Redun VAD Timer Type  Num  Type   Tran Tran Ecan Enable Per.
--- --- ----- ------ ----- --- ----- ----- ---- ------ ---- ---- ---- ------ ----
132 10     2  active  ena  ena  250   ITU     1 G.711u  ena  ena  ena  Dis     5
132 22     3  active  ena  ena  250   ITU     1 g.711u  ena  ena  ena  Dis     5

The dspcids output shows all the characteristics you set using the addcid command.

Display CID Command

The dspcid command shows the same information as the dspcids output, but for a specific CID. Example 22-11 shows the dspcid output.

Example 22-11 dspcid Output

smoke.1.3.VISM8.a > dspcid 131 9
  LCN number :     131
  CID number:     9
  Endpoint number :  50
  CidRowStatus:    active
  Type3redundancy:   enabled
  VAD:         disabled
  VADInitTimer:    200
  Profile type:    Custom
  Profile number:   100
  Codec type:     clr chan
  Cas transport:    enabled
  DTMF transport:   enabled
  Ecan on/off:     enabled
  ICS enable:     Disabled
  pkt period:     5

Commands for Verifying Voice Connections

This section describes the commands you use to verify voice connections in the MGX network:

• tstcon—Tests a connection's continuity

• tstdelay—Tests a connection's continuity and the round-trip delay

• dspconcnt—Lists a channel's statistics counters

• dspmngcidcnt—Lists an endpoint's managed CID counters

Test Connection Command

The tstcon command tests continuity on MGX network connections. If connection segments are failed or misconfigured, the tstcon command fails. The tstcon command does not test quality of service or connectivity beyond the MGX network.

Here is the tstcon command syntax:

tstcon <channel number>

The tstcon command has some limitations:

• It works only for local connections or connections in a tiered MGX network with BPX or MGX 8850-PXM45 backbone switches.

• It should be issued from both ends to completely verify connectivity.

• A passing result of the test does not guarantee the connection's end-to-end performance.

Test Delay Command

The tstdelay command is similar to the tstcon command in that it checks connection continuity. The tstdelay command also measures the round-trip delay through the network. The results are output on the CLI. The most recent delay measurement is also reported in the dspcon output.

Here is the tstdelay command syntax:

tstdelay <channel number>

The tstdelay output is shown in Example 22-12.

Example 22-12 tstdelay Output

smoke.1.3.VISM8.a > tstdelay 131

test type is..... 2

TestDelay in progress.

TestDelay Passed with 54 us.

Display Connection Count Command

The dspconcnt command lists historical connection statistics counters on the VISM. Use this command to learn how much traffic has been sent, received, or dropped on the voice connection. The cells reported in the dspconcnt output are counted at the segmentation and reassembly (SAR) processor in the VISM. Example 22-13 shows the dspconcnt output.

Example 22-13 dspconcnt Output

smoke.1.3.VISM8.a > dspconcnt 131

ChanNum:          131
Chan State:        okay
Chan XMT ATM State:    Normal
Chan RCV ATM State:    Normal
OAM Lpb Lost Cells:         0
AAL2 HEC Errors:          0
AAL2 CRC Errors:          0
AAL2 Invalid OSF Cells:       0
AAL2 Invalid Parity Cells:     0
AAL2 CPS Packet Xmt:        70327
AAL2 CPS Packet Rcv:        124971
AAL2 Invalid CID CPS:        0
AAL2 Invalid UUI CPS:        0
AAL2 Invalid Len. CPS:       0
AAL5 Invalid CPI:          0
AAL5 oversized SDU PDU:       0
AAL5 Invalid Len. PDU:       0
AAL5 PDU CRC32 Errors:       0
AAL5 Reassembly Timer expired PDU: 0

The dspconcnt output shows the following information:

• Channel state—okay or failed.

• Channel transmit ATM state—The channel state as reported to the ATM network and the remote end of the connection. For example, if the local line fails, the connection sends Operation, Administration, and Maintenance (OAM) alarm indicator signal (AIS) cells to the remote end (VISM or ATM interface) of the connection.

• Channel receive ATM state—The channel state reported from the ATM network.

• OAM loopback lost cells—The number of cells dropped while an OAM loopback was in progress.

• HEC errors—The number of cells with incorrect header error check (HEC) values.

• CRC errors—Cyclic Redundancy Check errors. This is a process that is used to check the integrity of a block of data. CRC is a common method of establishing that data was received correctly.

• Invalid OSF cells—The number of cells with an invalid offset field (OSF) in the start field of the common part sublayer protocol data unit (CPS-PDU).

• Invalid CID CPS—The number of cells with invalid CIDs in the CPS packet header.

• Invalid UUI CPS—The number of cells with invalid User-to-User Interface (UUI) fields in the CPS packet header.

• Invalid length—The number of cells with a payload length that does not match the length indicator (LI) in the CPS packet header.

• Invalid CPI—Invalid computer-to-PBX interface.

• Length Indicator (LI)—The number of cells with a payload length that does not match the LI in the CPS packet header.

• Sequence Number (SN)—The order in which the queues are serviced. It is strongly recommended that you do not change this value. 1 to 16.

• Parity (P)—The process of detecting whether bits of data were altered during transmission of that data.

• Oversize SDU PDU—Oversized service data unit (interface information that is unchanged from layer to layer) protocol data unit (packet).

• Invalid length PDU—Invalid protocol data unit (packet) length.

• PDU CRC32 errors—Protocol data unit for CRC errors.

• Reassembly timer expired PDU—A PDU can span multiple ATM cells. If the remainder of the PDU does not arrive within a set time period, the reassembly timer expires, and the PDU is discarded.

Display Managed CID Counter Command

Use the dspmngcidcnt command to display the managed CID count for a specified endpoint. Example 22-14 shows the dspmngcidcnt output.

Example 22-14 dspmngcidcnt Output

smoke.1.3.VISM8.a > dspmngcidcnt 50

 EndptNum:      50
 Lcn:        131
 Cid:        9
 SentPkts:      76843
 RcvdPkts:      76844
 SentOctets:     3301527
 RcvdOctets:     3301570
 LostPkts:      0
 Jitter:       0
 Latency:      0
 Ext AIS Rcvd:    0
 Ext RAI Rcvd:    0
 Ext Conn AIS Rcvd: 0
 Ext Conn RDI Rcvd: 0

The dspmngcidcnt output includes the following information:

• Sent packets—The number of packets sent to the network.

• Received packets—The number of packets received from the network.

• Sent octets—The number of octets sent to the network.

• Received octets—The number of octets received from the network.

• Lost packets—The number of packets lost during transmission.

• Jitter—The phase shift of digital pulses over a transmission medium.

• Latency—The time it takes to get information through a network; waiting time or time delay.

• External AIS received—The number of alarm indicator signals received from the line.

• External RAI received—The number of remote alarm indicators (RAIs) received from the line.

• External connection AIS received—An external connection AIS has been received.

• External connection RAI received—An external connection RAI has been received.

Introduction to Multiprotocol Label Switching

Multiprotocol Label Switching (MPLS) is a method of switching IP packets through a network by applying simple labels to packets. This allows devices in the network core to switch packets according to these labels with minimal lookup activity. Besides the obvious advantage of faster network transit, MPLS also provides the privacy and quality of service (QoS) advantages of connection-oriented services such as ATM without the complexity of manually creating fully-meshed PVCs.

MPLS integrates the performance and traffic-management capabilities of the data link layer (Layer 2) with the scalability and flexibility of network layer (Layer 3) routing. MPLS is applicable to networks using any Layer 2 switching, but it has particular advantages when applied to ATM networks. It integrates IP routing with ATM switching to offer scalable IP-over-ATM networks.

In contrast to label switching, conventional Layer 3 IP routing is based on the exchange of network reachability information. As a packet traverses the network, each router extracts all the information relevant to forwarding from the Layer 3 header. This information is then used as an index for a routing table lookup to determine the packet's next hop. This is repeated at each router across the network. At each hop in the network, the packet's optimal forwarding must again be determined.

The information in IP packets, such as information on IP Precedence and Virtual Private Network (VPN) membership, is usually not considered when packets are forwarded. To get maximum forwarding performance, typically only the destination address is considered. However, because other fields could be relevant, a complex header analysis must be done at each router the packet meets.

The main concept of MPLS is to include a label on each packet. Packets or cells are assigned short, fixed-length labels. Switching entities perform table lookups based on these simple labels to determine where data should be forwarded.

The label summarizes essential information about routing the packet:

• Destination

• Precedence

• VPN membership

• QoS information from Resource Reservation Protocol (RSVP)

• The packet's route, as chosen by traffic engineering (TE)

With label switching, the complete analysis of the Layer 3 header is performed only once: at the edge label switch router (LSR), which is located at each edge of the network. At this location, the Layer 3 header is mapped to a fixed-length label.

At each router across the network, only the label need be examined in the incoming cell or packet in order to send the cell or packet on its way across the network. At the other end of the network, an edge LSR swaps the label out for the appropriate header data linked to that label.

A key result of this arrangement is that forwarding decisions based on some or all of these different sources of information can be achieved by means of a single table lookup from a fixed-length label. For this reason, label switching makes it feasible for routers and switches to make forwarding decisions based on multiple destination addresses.

Label switching integrates switching and routing functions, combining the reachability information provided by the router function with the traffic engineering benefits achieved by the optimizing capabilities of switches.

ATM MPLS Technical and Business Benefits

MPLS, in conjunction with other standard technologies, offers many features that are critical for service providers:

• MPLS, in combination with the standard IP routing protocols OSPF and IS-IS, provides full, highly scalable support of IP routing within an ATM infrastructure.

• MPLS, in combination with Border Gateway Protocol (BGP), provides support for highly scalable IP VPN services. IP VPN services are an invaluable development in provider networks, giving enterprise customers a service that meets their needs for private, connectionless delivery of IP services.

• Service-Level Agreements (SLAs) can be provided in a form suitable for connectionless traffic. Cisco networks assist the process of providing SLAs by supporting MPLS in combination with forthcoming standards. Along with supporting VPNs, the ability to offer SLAs suitable for IP traffic is a critical requirement to meet new demands for IP services.

• Cisco's implementation of MPLS allows support for harder QoS where required using full ATM switch capabilities.

Cisco IP+ATM networks fully support all relevant IP routing protocols and MPLS while fully supporting traditional ATM services. MPLS and IP routing can readily be introduced into traditional ATM networks by using permanent virtual path (PVP) or PVC tunnels since MPLS-capable switches are continuously being introduced.

Cisco IP+ATM switches allow carriers to continue meeting their existing demands for virtual circuit services while adding optimized support for critically important new services: IP and IP VPNs. Furthermore, Cisco supports all the standards relevant to carrier-class IP services: MPLS, Multiprotocol BGP, other standard routing protocols, and MPLS traffic engineering.

Label Switching Advantages

MPLS offers many advantages over traditional IP over ATM.

When integrated with ATM switches, label switching uses switch hardware optimized to take advantage of the fixed length of ATM cells and to switch the cells at high speeds. For multiservice networks, label switching allows the Cisco WAN switch to provide ATM, Frame Relay, and IP Internet service all on a single platform in a highly scalable way. Support of all these services on a common platform provides operational cost savings and simplifies provisioning for multiservice providers.

For ISPs using ATM switches at the core of their networks, label switching allows the Cisco BPX 8600 series, the 8540 Multiservice Switch Router, MGX 8850-PXM45 (discussed in a moment), and other Cisco ATM switches to provide a more scalable and manageable networking solution than overlaying IP over an ATM network. Label switching avoids the scalability problem of too many router peers and provides support for a hierarchical structure within an ISP's network.

These MPLS benefits are analyzed in greater detail in the following list:

• Integration—When applied to ATM, MPLS integrates IP and ATM functionality rather than overlaying IP on ATM. This makes the ATM infrastructure visible to IP routing and removes the need for approximate mappings between IP and ATM features. MPLS does not need ATM addressing and routing techniques such as PNNI, although these can be used in parallel if required.

• Greater reliability—In wide-area networks (WANs) with ATM infrastructures, MPLS is an easy solution for integrating routed protocols with ATM. Traditional IP over ATM involves setting up a mesh of PVCs between routers around an ATM cloud, and the Next-Hop Resolution Protocol (NHRP) achieves a similar result with switched virtual circuits (SVCs). But a number of problems exist with this approach, all arising from the fact that the PVC links between routers are overlaid on the ATM network. This makes the ATM network structure invisible to the routers. A single ATM link failure could make several router-to-router links fail, creating problems with large amounts of routing update traffic and subsequent processing. (See the next section for details.)

• Better efficiency—Without extensive tuning of routing weights, all PVCs are seen by IP routing as single-hop paths with the same cost. This might lead to inefficient routing in the ATM network.

• Direct CoS implementation—When used with ATM hardware, MPLS makes use of the ATM queueing and buffering capabilities to provide different classes of service. This allows direct support of IP precedence and CoS on ATM switches without complex translations to the ATM Forum service classes.

• More elegant support of multicast and RSVP—In contrast to MPLS, overlaying IP on ATM has other disadvantages, particularly in support of advanced IP services such as IP multicast and RSVP. Support of these services entails much time and work in the standards bodies and implementation; the resulting mapping between IP features and ATM features is often approximate.

• VPN scalability and manageability—MPLS can make IP VPN services highly scalable and very easy to manage. VPN services are an important way to provide enterprises with private IP networks within their infrastructures. When an ISP offers a VPN service, the carrier supports many individual VPNs on a single infrastructure. With an MPLS backbone, VPN information can be processed only at the ingress and exit points, with MPLS labels carrying packets across a shared backbone to their correct exit point. In addition to MPLS, Multiprotocol (BGP) is used to deal with information about the VPNs. The combination of MPLS and Multiprotocol BGP makes MPLS-based VPN services easier to manage, with straightforward operations to manage VPN sites and VPN membership. It also makes MPLS-based VPN services extremely scalable, with one network able to support hundreds of thousands of VPNs.

• Reduces the load on network cores and is more robust—VPN services demonstrate how MPLS supports a hierarchy of routing knowledge. Additionally, you can isolate Internet routing tables from service provider network cores. Similar to VPN data, MPLS allows access to the Internet routing table only at the ingress and egress points of a service provider network. With MPLS, transit traffic entering at the edge of the provider's autonomous system can be given labels that are associated with specific exit points. As a result, internal transit routers and switches need only process the connectivity with the provider's edge routers, shielding the core devices from the overwhelming routing volume exchanged on the Internet. This separation of interior routes from full Internet routes also provides better fault isolation and improved stability.

• Traffic engineering capabilities—Other benefits of MPLS include traffic engineering capabilities needed for the efficient use of network resources. Traffic engineering lets you shift the traffic load from overutilized portions of the network to underutilized portions, according to traffic destination, traffic type, traffic load, time of day, and so on.

The Problem of Persistent Loops Due to Protocol Conflicts

If n routers are running OSPF and are connected in a full mesh over ATM PVCs, a single physical ATM link failure might result in ATM-layer rerouting of a large number of PVCs. If this takes too long, or if the ATM network cannot reroute PVCs, a large number of PVCs effectively fails.

The number of PVCs involved might be of the same order magnitude as n, and even n2 in some cases. In any case, it is likely to be seen by O(n) routers, where O(n) means "a number proportional to n." So, a single ATM link failure causes each of O(n) routers to send a link-state advertisement (LSA) of size (at least) O(n) to n – 1 neighbors. Thus, a single event in the ATM network results in O(n3) to O(n4) traffic.

When a router receives an LSA, it must immediately recalculate its routing table because it must not forward packets based on old routing information. The processor load caused by a storm of routing updates might cause the routers to drop or not send keepalive packets. This appears to the neighboring routers as further link failures. These lead to further LSAs being sent, which perpetuates the problem.

The net result is that a full-mesh network can become persistently unstable after a single network event.

This critical failure occurs because the routers do not see the state of the ATM links and switches directly. IS-IS has somewhat better performance than OSPF in full-mesh conditions because IS-IS has more sophisticated flooding capabilities. (These capabilities, especially the ability to pace and block flooding on some interfaces, are also becoming available on OSPF.) However, this does not address the underlying problem.

The solution is to enable IP routing to directly see the state of ATM links, which is what ATM MPLS does.

MPLS addresses the fundamental problem underlying the instability of the full-mesh network: the basic conflict between routing protocols. PNNI routing at the ATM layer can make decisions that conflict with OSPF or similar routing at the IP layer. These conflicting decisions can lead to persistent loops. The only reliable solution to this problem is to use the same routing protocol at the IP layer and ATM layer. This is exactly what MPLS does in ATM networks.

Cisco WAN Switches with MPLS Support

Figure 22-9 shows an example of an MPLS network.

Figure 22-9 MPLS Network Example

Based on the network routing protocol, a path (or route) is set up to all reachable IP networks. Simple label-switching tables identifying the labels and the destination interface are set up on all intermediate nodes. The nodes at the edge of the MPLS network attach the appropriate labels to the IP packets. The nodes in the network core simply switch the packets from one interface to the next based on the label. For example, if a packet with label 2A comes in on interface 01, it is switched to interface 06, and the label is changed to 15.

Label switching is similar to switching cells in an ATM network: Instead of a VPI and a VCI, there is a label. Because of this similarity, using an MPLS-enabled ATM network in the core is the ideal solution, especially in cases where ATM networks are already deployed.

An LSR is a core device that switches labeled packets according to predefined switching tables. An LSR can be a switch or a router. BPX 8650 switches (a BPX switch plus a 7200-series router) and MGX 8850-PXM45 switches (with RPM installed) are examples of LSRs.

An Edge LSR (ELSR) or Label Edge Router (LER) is an edge device that performs initial packet processing and classification and applies the first label. An ELSR can be either a router or a switch with built-in routing. The RPM installed in an MGX switch is an example of an ELSR.

A Label Switch Controller (LSC) is an MPLS router that controls the operation of an ATM switch in such a way that the two function together as a single ATM-LSR. An LSR comprises a switch and an LSC. A 7200 series router is an LSC for the BPX switch; an RPM is an LSC for the MGX 8850-PXM45 switch.

MPLS Features Supported on the MGX Switch

This section provides a high-level description of the MPLS features supported on the RPM installed in an MGX switch running Release 1.1.x firmware.

The RPM supports the following MPLS features:

• The RPM as an ELSR or LER

• Support for MPLS VPNs

• Support for QoS

• Support for MGX switches (with PXM1) interworking with MGX 8850-PXM45 switches via MPLS Virtual Switch Interface (VSI) virtual trunks

• Support for MGX switches (with PXM1) interworking with BPX 8650 switches via MPLS VSI virtual trunks

The RPM as an Edge Label Switch Router

The RPM installed in an MGX switch is an ELSR or LER. As an ELSR, the RPM is responsible for initial packet processing and classification. It also applies the first label to the packets.

MPLS VPN Support on RPM

MPLS VPN support on RPM is described in greater detail in the upcoming section, "MPLS and Virtual Private Networks Using the Route Processor Module."

The VPN offers private connectivity over a public infrastructure. Each customer is assigned a VPN ID. You can think of the VPN ID as a prefix or extension of the IP address. For example, if a destination IP address is 10.10.15.2 and the VPN ID is 243, the packet destination is effectively 243.10.10.15.2, uniquely identifying the destination. Even if another customer is using the same IP address, the VPN ID is different, making the packet address different as well. In the MPLS network, the VPN identifier and the destination IP address are associated with a label.

The VPN is also isolated by the routing protocol (BGP) so that routing updates are exchanged only between members of the same VPN. The router at one customer's site does not even know about another customer's routers.

Figure 22-10 shows an example of VPNs in the MPLS network. Company A and Company B are connected to the same public network; however, they each have a VPN that behaves like a private network.

Figure 22-10 Example of VPNs in the MPLS Network

MPLS QoS Support on RPM

Customers have different types of traffic that they want to send to the service provider. MPLS allows the service provider to assign a different label to each traffic class. This label determines how traffic will be handled in the network.

The MPLS QoS solution does not map different traffic classes into different virtual circuits, as is done in ATM. MPLS simply applies a different label. These labels move the packet from end to end, maybe over a different path. Each switch along the way has a label that tells it the packet's CoS.

MGX PXM1 MPLS Interworking with MGX 8850-PXM45 and BPX Switches

This feature allows RPMs as ELSRs in PXM1-based platforms to interwork with the MGX 8850-PXM45 or BPX 8650 LSC function. The MPLS VSI virtual trunks feature enables the definition of one virtual path (VP) tunnel per ELSR on a PXM1-based platform to be mapped to one VSI virtual trunk under the control of the LSC on the attached backbone switch.

Figure 22-11 shows the MPLS interworking feature for MGX 8850-PXM45 switches.

Figure 22-11 The MPLS Interworking Feature

MPLS Networks Using the MGX Switch

This section describes how the MGX switch is placed in an MPLS network. It shows how the MGX switches with the BPX ATM MPLS core, the MGX 8850-PXM45 ATM MPLS core, and the IP MPLS core.

MGX Switches with the BPX ATM MPLS Core

This ATM MPLS architecture uses BPX 8650 ATM LSRs. The ELSR or LERs in this network are RPMs installed in MGX 8230/8250/8850-PXM1 switches.

The MGX switches are connected to the BPX switches by T3, E3, OC-3/STM1, or OC-12/STM4 ATM links.

Figure 22-12 shows an ATM MPLS core with MGX switches with RPMs as ELSRs.

Figure 22-12 ATM MPLS Core with MGX Switches

Cisco MGX 8230, 8250, and 8850-PXM1 switches do not yet support LSCs. This means that all MPLS traffic to RPMs must be carried inside a PVC or a PVP. PVCs are used with packet-based MPLS. If an MGX switch is used with ATM MPLS, the connections to the RPMs must be PVPs, which are used as MPLS VP tunnels.

Two options exist for the PVP connections, as shown in Figure 22-13. In the first option, at least two separate ATM lines are used between the MGX switch and the BPX switch. One line is the feeder trunk, which carries all but MPLS traffic, and the second line carries PVPs from the RPMs to the BPX switch. The second line is a UNI or NNI port on the MGX switch, with several VSI virtual trunk endpoints on the BPX switch.

Figure 22-13 PVP Connections

The second line is required because the BPX switch does not support virtual trunk endpoints on interfaces that are configured as feeder trunks. Another option involves using three or four lines with the PVPs distributed across them, increasing the available bandwidth. In this topology, additional lines are configured in the same fashion as the second UNI or NNI (nonfeeder trunk) link.

If two or three UNI or NNI lines are used to carry MPLS PVPs, these can be connected from one MGX switch to two or three different BPX nodes. Non-MPLS traffic from the MGX switch is still carried on the feeder trunk to a single BPX switch.

It is possible to carry all traffic (MPLS and non-MPLS) on the feeder trunk between the MGX and BPX switches. This option requires loopback cables on the BPX node and additional connections between the BPX feeder trunk and UNI or NNI ports.

MGX Switches with the MGX 8850-PXM45 ATM MPLS Core

Using an MGX 8850-PXM45 ATM MPLS core for MGX switches is similar to using a BPX core. The main difference is that the LSC for the MGX 8850-PXM45 switch is an RPM card module rather than an external router.

Figure 22-14 shows MGX 8850-PXM45 switches and MGX PXM1 switches in an ATM MPLS network.

Figure 22-14 Cisco Switches in an ATM MPLS Network

Like a BPX ATM MPLS core, you must set up a second line between the MGX PXM1 and the MGX 8850-PXM45 switches to carry the PVPs from the RPM ELSR.

MGX Switches with the IP MPLS Core

It is possible to set up the MGX switches without an ATM MPLS core. In this case, PVCs are required between RPMs in the network that need to pass traffic between them. The ATM backbone can be BPX, MGX 8850-PXM45, or other-vendor switches, but it is not an MPLS-enabled network. The ATM backbone network simply transports ATM cells from one RPM to another without any knowledge of MPLS.

Figure 22-15 shows an example of MGX switches and an IP MPLS core.

Figure 22-15 Cisco Switches in an IP MPLS Core

Refer to this Web site for more information on the benefits of MPLS: http://www.ciscopress.com/book.cfm?series=1&book=168.

Setting Up MPLS on the MGX Switch

This section describes the steps required to set up MPLS on the RPM. This section does not provide detailed configuration information. It is intended as a guide for you to plan for MPLS in your network.

Network Topology

Use Figure 22-16 as a reference for the steps described in this section.

Figure 22-16 Setting Up MPLS on the MGX Switch

Follow these steps to set up MPLS on the MGX switch:

You have completed the steps necessary for setting up MPLS on the MGX switch.

MPLS and Virtual Private Networks Using the Route Processor Module

Virtual Private Networks (VPNs) provide the appearance, functions, and usefulness of a dedicated private network. The VPN feature for MPLS allows a Cisco IOS network to deploy scalable IPv4 Layer 3 VPN backbone service with private addressing, controlled access, and service-level guarantees between sites.

VPNs are supported by service provider networks over which labeled packets are forwarded from RPM ELSRs to other RPM ELSRs. A VPN service creates multiple private network environments within the public infrastructure. Service providers can use VPNs to target a given clientele and to deliver individualized private network services to that clientele in a secure IP environment by using the public infrastructure.

VPN Requirements

Here are the requirements for an effective VPN:

• Privacy—All IP VPN services offer privacy over a shared (public) network infrastructure, the most well-known solution of which is an encrypted tunnel. An IP VPN service must offer private addressing, in which addresses within a customer private network do not need to be globally unique.

• Scalability—IP VPN services must scale to serve hundreds of thousands of sites and users. An IP VPN service should also serve as a management tool for service providers to control access to services, such as closed user groups for data and voice services. Controlled access places performance limits on authorized programs, processes, or other systems in a network.

• Flexibility—IP VPN services must accommodate any-to-any traffic patterns and be able to accept new sites quickly, connect users over different media, and meet transport and bandwidth requirements of new intranet applications.

• Predictable performance—Intranet applications supported by an IP VPN service require different classes of service. The service level performance between customer sites must be guaranteed. Examples include widespread connectivity required by remote access for mobile users and sustained performance required by interactive intranet applications in branch offices.

MPLS VPN Features

Beyond the functions of an IP VPN, the VPN features for MPLS allow a Cisco IOS network to deploy the following scalable IPv4 Layer 3 VPN backbone services:

• Connectionless service—MPLS VPNs are connectionless. They also are significantly less complex because they do not require tunnels or encryption to ensure network privacy.

• Centralized service—VPNs in Layer 3 privately connect users to intranet services and allow flexible delivery of customized services to the user group represented by a VPN. VPNs deliver IP services such as multicast, QoS, and telephony support within a VPN, and centralized services such as content and Web hosting. Combinations of services can be customized for individual customers.

• Scalability—MPLS-based VPNs use a Layer 3 connectionless architecture and are highly scalable.

• Security—MPLS VPNs provide the same security level as connection-based VPNs. Packets from one VPN cannot accidentally go to another VPN. At the edge of a provider network, incoming packets go to the correct VPN. On the backbone, VPN traffic remains separate.

• Easy to create—Because MPLS VPNs are connectionless, it is easy to add sites to intranets and extranets and to form closed user groups. A given site can have multiple memberships.

• Flexible addressing—MPLS VPNs provide a public and private view of addresses, allowing customers to use their own unregistered or private addresses. Customers can freely communicate across a public IP network without network address translation (NAT).

• Straightforward migration—MPLS VPNs can be built over multiple network architectures, including IP, ATM, Frame Relay, and hybrid networks. There is no requirement to support MPLS on the customer edge (CE) router.

Supported Platforms

The MGX 8850 node with RPM supports VPNs, as do all Cisco routers from the 3600 series up, the 6400 series, and several other devices. Any LSR-capable platform can serve in the backbone including the LS 1010 ATM switch, the 8540 MSR, and the BPX 8650 switch. Non-MPLS-capable switches can also be used, because they can carry MPLS over PVCs or PVPs.

How Do VPNs Work?

Each VPN is associated with one or more VPN routing/forwarding instances (VRFs), which define a VPN at a customer site attached to a PE router. A VRF table consists of the following:

• IP routing table

• Derived Cisco Express Forwarding table

• Set of interfaces that use the forwarding table

• Set of rules and routing protocol variables that determine what goes into the forwarding table

VPNs for MPLS

A customer site can be a member of multiple VPNs. However, a site can be associated with only one VRF. A customer site's VRF contains all routes available to the site from the associated VPNs.

The IP routing table and CEF table for each VRF store packet-forwarding information. (Together, these tables are analogous to the forwarding information base [FIB] used in MPLS.) A logically separate set of routing and CEF tables is constructed for each VRF. These tables prevent packets from being forwarded outside a VPN and prevent packets outside a VPN from being forwarded to a router within the VPN.

VPN Route-Target Communities and Export and Import Lists

The distribution of VPN routing information is controlled through the use of VPN route-target communities, implemented by BGP extended communities. Distribution works as follows:

• When a VPN route is injected into BGP, it is associated with a list of VPN route-target communities. This list is set through an export list associated with the VRF from which the route was learned.

• Associated with each VRF is an import list of route-target communities that defines values to be verified by the VRF table before a route is deemed eligible for import into the VPN routing instance. For example, if a given VRF's import list includes community distinguishers A, B, and C, any VPN route carrying A, B, or C is imported into the VRF.

IBGP Distribution of VPN Routing Information

A PER learns an IP prefix from a CE router through static configuration, a BGP session, RIP, or OSPF. The PER then generates a VPN-IPv4 (vpnv4) prefix by linking an 8-byte route distinguisher to the IP prefix. The VPN-IPv4 address uniquely identifies hosts within each VPN site, even if the site uses globally nonunique (unregistered private) IP addresses. The route distinguisher used to create the VPN-IPv4 prefix is specified by a configuration command on the PER.

BGP uses VPN-IPv4 addresses to distribute network reachability information for each VPN within a service provider network. In building and maintaining routing tables, BGP sends routing messages within (interior BGP [IBGP]) or between (exterior BGP or [EBGP]) IP domains.

BGP propagates vpnv4 information using BGP multiprotocol extensions to handle extended addresses. Refer to RFC 2283, "Multiprotocol Extensions for BGP-4." BGP propagates reachability information (expressed as VPN-IPv4 addresses) among PE routers; reachability information for a given VPN is propagated only to members of that VPN. BGP multiprotocol extensions identify valid recipients of VPN routing information.

Label Forwarding

Based on the routing information stored in each VRF's IP routing and CEF tables, Cisco MPLS uses extended VPN-IPv4 addresses to forward packets to their destinations.

To achieve this, an MPLS label is associated with each customer route. The PE router assigns the route originator's label and directs data packets to the correct CE router. Tag forwarding across the provider backbone is based on dynamic IP paths or traffic-engineered paths.

A customer data packet has two levels of labels attached when it is forwarded across the backbone:

• The top label directs the packet to the correct PE router.

• The second label indicates how that PE router should forward the packet.

The PE router associates each CE router with a forwarding table that contains only the set of routes that are available to that CE router.

RPM Memory Locations

The RPM card module has several memory locations that it uses to store and manage software code, configuration information, and other information.

The RPM boot Flash is used to store a boot image. This boot image is used by the RPM if a suitable IOS image is unavailable. When you install a new RPM, the boot image is loaded, and you must configure the RPM to upload the IOS image from the PXM1 hard drive.

The startup configuration file is stored in nonvolatile random-access memory (NVRAM).

Dynamic random-access memory (DRAM) on the RPM is used to run the IOS software, and it stores a working copy of the configuration files. As soon as the initial RPM configuration is done, the RPM uploads the IOS image into DRAM.

Static random-access memory (SRAM) on the RPM is used for shared-memory switching of packets. This memory is used when routing data packets from one interface to another.

The PXM1 has an IDE hard drive that the MGX switch uses to store firmware and configuration files. The RPM also utilizes this drive for IOS image and configuration storage. If you want to store the IOS image or RPM configuration file on the PXM hard drive, you must do so manually from the RPM CLI.

RPM Port Numbering

This section describes how RPM ports are numbered so that when you configure the RPM you can correctly identify the interfaces.

Definition

The port-numbering scheme on the RPM is as follows:

• LAN interfaces are identified as chassis-slot/slot/port.

• The top-rear interface card is slot 1.

• The bottom-rear interface card is slot 2.

• Ports are numbered 1 to 4 from top to bottom.

• The ATM cell bus interface is always port 1.

Cisco IOS Command-Line Interface

This section describes how to use the Cisco IOS command-line interface (CLI). This section is not intended to be a complete tutorial on IOS commands. Instead, it provides novice users with the fundamental skills to use the CLI.

It is assumed that you do not have experience on Cisco IOS products. However, it is highly recommended that you attend appropriate Cisco training courses before attempting to configure an RPM in a live network environment.

RPM CLI Access

The RPM CLI can be accessed using any of the following three methods:

• Console port on the front of the RPM—The RPM has an RJ-45 connector on the front of the card module. A PC or dumb terminal can be directly attached to this port with an EIA/TIA-232 to RJ-45 cable for CLI access. The console port is the only way to access the RPM CLI when the card module is first installed into an MGX chassis.

• cc from another MGX card—You can access the RPM CLI using the cc (change card) command from any of the other cards in the MGX switch. The ATM switch interface on the RPM must be enabled before you can use the cc command.

• Telnet from a workstation, PC, or another router—The RPM CLI can be accessed from a PC or workstation on any of the LANs attached to the RPM. Also, after the RPM is installed and has PVCs to other RPMs or routers in the network, you can Telnet to the RPM CLI remotely from these other devices.

CLI Modes

The RPM, like all Cisco routers, has seven modes of operation:

• User EXEC mode— Once you have logged into the router CLI, be aware that you will have limited read access to the status and configuration of the router in this mode.

• Privileged EXEC mode—In privileged EXEC mode, you can access detailed status and configuration information and modify the router's configuration files. To enter privileged EXEC mode, use the enable command. An additional password might be required to access privileged EXEC mode.

• ROM monitor mode—ROM monitor mode is used when a router is first initialized and does not have a configuration file. Interrupting the boot process with a keyboard break sequence also starts ROM monitor mode.

• Setup mode—Setup mode is a prompted configuration sequence that is used when a router is first initialized.

• RX boot mode—The boot helper software that is used if the router cannot access the Cisco IOS image.

• Global configuration mode—A mode in which configuration changes can be made that affect the general router operation. For example, changing the router host name is a global configuration command.

• Other configuration modes—Other configuration modes for modifying specific router elements are accessed from configuration mode. For example, to make configuration changes on an Ethernet interface, enter interface ethernet 9/1/1 while in configuration mode.

Entering Commands

When you are logged into the RPM, you enter commands at the command prompt. Most commands can be abbreviated using a few letters, provided that the abbreviation is unique. For example, you can enter sho int instead of show interface. Entering sho i is not enough, because several keywords start with the letter i, such as ip and ipx. In this book, all commands and keywords are spelled out in their entirety.

The Tab key completes an abbreviated word or provides you with choices based on the letters you have entered. For example, if you enter sho and then press Tab, the system spells out show on the command line.

The ? key provides the next keyword or parameter if you are unsure of your options. For example, if you enter show ?, the system displays a list of possible choices, such as interface, configuration, and memory.

Preceding a command with no negates most configuration commands. For example, to assign an IP address to an interface, use the ip address command. To remove an IP address from an interface, use the no ip address command.

Changing the RPM Configuration

Before making changes to a configuration file, you should view the file using one of the following commands:

• show running-config
• show startup-config

When you enter configure terminal, you execute the configuration commands from the terminal. In this case, you make changes to the running configuration.

If you want to make changes to a configuration file other than the current running configuration, you need to copy the file into the running configuration by entering one of the following commands:

• copy startup-config running-config—Copies the startup configuration into the running configuration. When this command is complete, you can use the configure terminal command to enter configuration mode.

• copy c:filename running-config—Copies the configuration file named filename that is stored on the PXM hard drive into the running configuration. When this command is complete, you can use the configure terminal command to enter configuration mode.

  NOTE

  The configuration file named filename is stored in the RPM directory of the PXM hard drive.

• copy tftp running-config—Copies a configuration file from a Trivial File Transfer Protocol (TFTP) server into the running configuration. You are prompted for the server name or address and the filename. When this command is complete, you can use the configure terminal command to enter configuration mode.

If you want to go from a specific configuration mode (for example, interface configuration mode) to global configuration mode, use the exit command. From any configuration mode, press Ctrl-Z to exit. The changes you made are automatically stored in the running configuration file in RAM.

After you determine that the new configuration is correct, you must save your changes to the startup configuration file. Saving the changes ensures that the router uses the changes when you copy the startup configuration file into memory or perform a reload. Save the configuration using one of the following methods:

• copy running-config startup-config—Saves the configuration variables to the startup configuration file in NVRAM.

• copy running-config c:filename—Saves the configuration variables to a file named filename on the PXM hard drive.

• copy running-config tftp—Saves the configuration variables to a remote server on the network. The variable tftp represents the target server type.

Example 22-15 shows an example of making a configuration change to the RPM.

Example 22-15 Making a Configuration Change to the RPM

RPM-PR_NY_9>enable
Password:

RPM-PR_NY_9#configure terminal
Enter configuration commands, one per line. End with CNTL/Z.

RPM-PR_NY_9(config)#interface switch 9/1

RPM-PR_NY_9(config-if)#ip address 10.10.12.34 ?
 A.B.C.D IP subnet mask

RPM-PR_NY_9(config-if)#ip address 10.10.12.34 255.255.255.0 ?
 secondary Make this IP address a secondary address
 <cr>

RPM-PR_NY_9(config-if)#ip address 10.10.12.34 255.255.255.0

RPM-PR_NY_9(config-if)#^Z

RPM-PR_NY_9#copy running-config startup-config
Destination filename [startup-config]?
Building configuration...
[OK]

RPM-PR_NY_9#

Commands for Configuring the RPM

This section describes the commands you use to configure the RPM:

• enable—Accesses privileged EXEC mode. This command might require a password.

• show running-config—Displays the running configuration file.

• show startup-config—Displays the startup configuration file.

• copy—Copies a configuration file from one location to another.

• reload—Resets the RPM and loads the Cisco IOS image.

• configure terminal—Enters configuration mode so that you can modify a configuration file.

• boot system—Defines the location and filename of the IOS image for the RPM to boot from.

• hostname—Sets the RPM host name.

• enable password—Defines an enable password.

• line—Defines a user access line.

• password—Defines a user access line password.

• rpmrscprtn—Defines the resource partitions on the RPM.

Enable Command

The enable command starts privileged EXEC mode on the IOS CLI. Many of the commands for the RPM require that you be in privileged EXEC mode. The enable command might require a password.

When you enter privileged EXEC mode, the CLI prompt changes from hostname> to hostname#.

Show Running Configuration and Show Startup Configuration Commands

The show running-config and show startup-config commands output the running or startup configuration files. Use these commands to verify the RPM's configuration.

The output is often several screens in length. Use the Spacebar to move forward one screen; use the Enter key to move forward one line.

Example 22-16 shows the first of three screens for the show running-config output.

Example 22-16 show running-config Output, Page 1

Current configuration:
!
version 12.1
no service pad
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
!
hostname rpm01
!
boot system c:rpm-js-mz.120-2.5.T
boot system c:rpm-js-mz.121-3.T
enable password cisco
!
!
!
!
!
ip subnet-zero
!
cns event-service server
!
!
!

Example 22-17 shows the second of three screens for the show running-config output.

Example 22-17 show running-config Output, Page 2

interface Ethernet2/1
 no ip address
 no ip route-cache
 no ip mroute-cache
 shutdown
!
interface Ethernet2/2
 no ip address
 no ip route-cache
 no ip mroute-cache
 shutdown
!
interface Ethernet2/3
 no ip address
 no ip route-cache
 no ip mroute-cache
 shutdown
!
interface Ethernet2/4
 no ip address
 no ip route-cache
 no ip mroute-cache
 shutdown
!

Example 22-18 shows the third of three screens for the show running-config output.

Example 22-18 show running-config Output, Page 3

interface Switch1
 no ip address
 no ip route-cache
 no ip mroute-cache
 no atm ilmi-keepalive
!
!
ip classless
no ip http server
!
!
!
line con 0
 transport input none
line aux 0
line vty 0 4
 password cisco
 no login
!
rpmrscprtn PAR 100 100 0 255 0 3840 4000
addcon auto_synch off
end

Copy Command

The copy command copies a configuration file to a specified location. For example, you can save the running configuration file to the PXM1 hard drive. Use this command to save changes to the running configuration. In some cases, you are prompted to confirm the copy command.

Here is the copy command syntax:

copy <source> <destination>

Both the source and destination can be specified as the following:

• running-config—The running configuration stored in RAM.

• startup-config—The startup configuration stored in NVRAM.

• c:filename—A configuration file named filename is stored on the PXM1 hard drive in the RPM subdirectory.

• tftp—A configuration file stored on a remote TFTP server. If you use this keyword, you are prompted for additional information, including the server's name or IP address and the filename.

For example, type copy running-config startup-config to copy the running configuration to the startup configuration. Type copy startup-config c:start_lab_test to copy the startup configuration to the PXM1 hard drive with a filename of start_lab_test.

Reload Command

The reload command reboots the RPM and loads the IOS image as specified in the startup configuration. Use this command after you configure the RPM to load the IOS image from the PXM1 hard drive.

You are prompted to confirm the reload. If the new IOS image is significantly different from the previous one, some configuration on the RPM might be changed or lost. Use caution when using this command.

Configure Terminal Command

The configure terminal command starts configuration mode from the terminal (CLI). Use this command when you want to change the RPM running configuration. When you start configuration mode, the CLI prompt changes from hostname# to hostname (config)#. You must be in privileged EXEC mode to issue the configure terminal command.

When you start configuration mode, you can make general configuration changes that affect the RPM as a whole (global configuration mode). You can make specific configuration changes by specifying an element on the RPM, such as an Ethernet interface. The CLI prompt changes to reflect the specific configuration mode. For an interface, the CLI prompt changes to hostname(config-if)#. Use the exit command to end a specific configuration mode.

After you finish making configuration changes, press Ctrl-Z to exit configuration mode. Remember to use the copy command if you want to save the changes to anywhere other than the running configuration.

Boot System Command

The boot system command specifies the IOS image that the RPM should load on startup. In most cases, you configure the RPM to load the IOS image from the PXM1 hard drive. It is possible to store the IOS image at other locations, such as a TFTP server. You must be in global configuration mode to use the boot system command.

Here is the boot system command syntax:

boot system c:filename

filename is the name of the IOS image on the PXM1 hard drive. The file must be in the RPM subdirectory on the PXM1.

For example, type boot system c:rpm-js-mz.121-5.3.T_XT to load the IOS image file rpm-js-mz.121-5.3.T_XT from the PXM1 hard drive.

Hostname Command

The hostname command sets the RPM host name. You must be in global configuration mode to use the hostname command.

Here is the hostname command syntax:

hostname <hostname>

hostname is a character string less than 63 characters in length. The host name must start with a letter, end with a letter or number, and have as interior characters only letters, digits, and hyphens. Valid host names are router, RPM-cardslot9, and San-Jose5. Host names 5-san-jose, san jose 5, and RPM#9.2 are invalid.

Enable Password Command

The enable password global configuration command sets a privileged EXEC password. It is recommended that you set up an enable password to prevent unauthorized users from changing the RPM configuration. You must set up an enable password if you want to remotely access the RPM CLI in any way (from the PXM1 or using Telnet) except from the console port on the RPM front card.

Here is the enable password command syntax:

enable password {0 | 7 | level} [level-number] <password>

The keyword and parameter options are as follows:

• 0—An unencrypted password follows. If no option is specified, the password is encrypted and is not hidden.

• 7—A hidden password follows. If no option is specified, the password is encrypted and is not hidden.

• level—Specifies a user EXEC-level password.

• level-number—The user EXEC level between 1 and 15.

• password—The password character string.

For example, type enable password 0 cisco=enable to change the enable password (unencrypted) to cisco=enable; type enable password 123dog to change the enable password (encrypted) to 123dog.

Line Command

The line global configuration command sets up user access lines on the RPM. The line command also starts line-specific configuration mode. When you are in this mode, you can change the access characteristics, such as the password, session timers, and event logging. You must set up user access lines to remotely access the RPM CLI.

Here is the line command syntax:

line {aux | console | vty} <first-line-number> <last-line-number>

The keyword and parameter options are as follows:

• aux—Configures the RPM auxiliary port.

• console—Configures the RPM console port.

• vty—Configures a virtual terminal. Virtual terminal lines include Telnet and PXM1 CLI sessions.

• first-line-number—The first line number of a range. Up to six virtual terminal lines are supported. The RPM auxiliary and console ports are always line number 0.

• last-line-number—The last line number of a range. This parameter is not specified for RPM auxiliary and console ports.

For example, type line vty 0 4 to configure virtual terminal lines 0 to 4; type line console 0 to configure the RPM console port.

Password Command

The password line-specific configuration command sets a password for accessing the RPM CLI from a line (auxiliary, console, or virtual terminal). You must specify a password for virtual terminal lines on the RPM if you want to remotely access the RPM CLI.

Here is the password command syntax:

password {0 | 7} <password>

The keyword and parameter options are as follows:

• 0—An unencrypted password follows. If no option is specified, the password is encrypted and is not hidden.

• 7—A hidden password follows. If no option is specified, the password is encrypted and is not hidden.

• password—The password character string.

For example, type password 0 CLIpassword to change the password (unencrypted) to CLIpassword; type password mgx8850-2 to change the enable password (encrypted) to mgx8850-2.

RPM Resource Partition Command

Similar to other card modules in the MGX switch, the RPM must have resource partitions configured. The rpmrscprtn global configuration command sets up the partitions on the RPM. You must set up partitions before you can configure any connections on the RPM.

Here is the rpmrscprtn command syntax:

rpmrscprtn {par | tag | pnni} <ingress-percent> <egress-percent>
  <minimum-VPI> <maximum-VPI> <minimum-VCI> <maximum-VCI> <LCNS>

The keyword and parameter options are as follows:

• par (Portable AutoRoute), tag (MPLS), or pnni—The controller type you want to define.

• ingress-percent—The percentage of the ingress bandwidth on the ATM switch interface that can be allocated by the controller type. The aggregate of the ingress bandwidth across all three controllers can exceed 100 percent.

• egress-percent—The percentage of the egress bandwidth on the ATM switch interface that can be allocated by the controller type. The aggregate of the egress bandwidth across all three controllers can exceed 100 percent.

• minimum-VPI—The minimum VPI value that can be assigned on PVCs on this controller. The VPI ranges on the three controllers can overlap. Valid values are from 0 to 255.

• maximum-VPI—The maximum VPI value that can be assigned on PVCs on this controller. The VPI ranges on the three controllers can overlap. Valid values are from 0 to 255.

• minimum-VCI—The minimum VCI value that can be assigned on PVCs on this controller. The VCI ranges on the three controllers can overlap. Valid values are from 0 to 3840.

• maximum-VCI—The maximum VCI value that can be assigned on PVCs on this controller. The VCI ranges on the three controllers can overlap. Valid values are from 0 to 3840.

• LCNS—The total number of logical connections that can use this controller. Valid values are from 0 to 4047.

For example, type rpmrscprtn par 100 100 0 255 0 3840 4047 to allow the PAR controller access to the full range of resources.

Commands for Setting Up the RPM ATM Switch Interface

This section describes the commands you use to set up the RPM ATM switch interface. The switch interface is the ATM interface between the RPM and the cell bus (PXM1).

• show interface—Displays the status of a specific interface or all interfaces on the RPM.

• interface—Creates or accesses the configuration of an interface or subinterface.

• shutdown—Disables an interface. The no shutdown command activates an interface.

Show Interface Command

The show interface command output lists detailed interface configuration and status information. You can specify a particular interface. Otherwise, all interfaces are listed.

Here is the show interface command syntax:

show interface [switch <slot-number>/<interface-number>.[subinterface-number]]

The keyword and parameter options are as follows:

• switch—This optional keyword shows the switch interface. If you do not specify a keyword, all interfaces are listed.

• slot-number—If you specify the switch keyword, you must specify the RPM card slot number.

• interface-number—If you specify the switch keyword, you must specify the interface number. For the RPM switch interface, the only valid value is 1.

• subinterface-number—You can also specify a subinterface number.

For example, type show interface 9/1 to list information on the ATM switch interface of the RPM in slot 9. Type show interface to list information on all interfaces on the RPM.

Example 22-19 shows the show interface switch output.

Example 22-19 show interface switch Output

rpm01#sho int switch 9/1

Switch1 is up, line protocol is up
 Hardware is ENHANCED ATM PA
 MTU 4470 bytes, sub MTU 4470, BW 149760 Kbit, DLY 100 usec,
   reliability 255/255, txload 1/255, rxload 1/255
 Encapsulation ATM, loopback not set
 Keepalive not supported
 Encapsulation(s): AAL5
 4096 maximum active VCs, 6 current VCCs
 VC idle disconnect time: 300 seconds
 0 carrier transitions
 Last input never, output 00:00:00, output hang never
 Last clearing of "show interface" counters never
 Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
 Queueing strategy: Per VC Queueing
 5 minute input rate 0 bits/sec, 1 packets/sec
 5 minute output rate 1000 bits/sec, 1 packets/sec
   2090 packets input, 101234 bytes, 0 no buffer
   Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
   0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
   2118 packets output, 179057 bytes, 0 underruns
   0 output errors, 0 collisions, 1 interface resets
   0 output buffer failures, 0 output buffers swapped out

Useful information in the show interface switch output includes the following:

• Interface status—Up or down

• Line protocol status—Up or down

• Maximum Transmission Size (MTU)—The largest packet size, in bytes, permitted on the interface

• Bandwidth (BW)—The interface bandwidth, in kbps

• Encapsulation—Always ATM

• Maximum number of virtual circuits (VCs) allowed

• Current number of VCs—The current number of VCs being used

• Queue status—The current queue status

• Ingress and egress traffic counters

You can clear the traffic counters using the clear counters switch command.

Interface Command

The interface global configuration command accesses interface-specific configuration mode. You also use the interface command to create a new subinterface. When you use the interface command, the CLI prompt changes from hostname(config)# to hostname(config-if)#.

Here is the interface command syntax:

interface [switch <slot-number>/<interface-number>.[subinterface-number]]

The keyword and parameter options are as follows:

• switch—This optional keyword shows the switch interface.

• slot-number—If you specify the switch keyword, you must specify the RPM card slot number.

• interface-number—If you specify the switch keyword, you must specify the interface number. For the RPM switch interface, the only valid value is 1.

• subinterface-number—You can also specify a subinterface number.

For example, type interface switch 9/1 while in global configuration mode to configure the ATM switch interface on the RPM in card slot 9.

Shutdown Command

The shutdown interface-specific configuration command is used to deactivate an interface. Use the no shutdown command to activate an interface. By default, the ATM switch interface is inactive. You must activate it using the no shutdown command before the RPM can send and receive cells to and from the cell bus.

How to Set Up the RPM

This section describes the steps you must follow to set up the RPM in your MGX switch. This procedure assumes that the RPM is newly installed and is set with the factory defaults:

You have completed the steps necessary to set up the RPM in your MGX switch.

Configuring Subinterfaces

A subinterface is a logical interface on a physical interface such as the RPM ATM switch interface. Multiple subinterfaces can exist on a single physical interface.

A permanent virtual circuit (PVC) on the RPM is associated with a subinterface. You cannot terminate a PVC on the ATM switch interface. Some subinterfaces support multiple PVCs (multipoint); others support only one PVC (point-to-point). Figure 22-17 shows a multipoint subinterface and a point-to-point subinterface.

Figure 22-17 Multipoint and Point-to-Point Subinterfaces

A subinterface is assigned one IP address regardless of the number of PVCs that terminate on it. In order for multiple PVCs to terminate on one subinterface, the IP addresses of all meshed subinterfaces must be on the same network or subnetwork.

Subinterface Example

Figure 22-18 shows two subinterfaces on the RPM. Each subinterface is identified as chassis-slot/interface.subinterface. The chassis-slot is the RPM's card slot number, the interface is always 1, and the subinterface is a number that identifies the subinterface.

Figure 22-18 Subinterfaces on the RPM

In Figure 22-18, one of the subinterfaces is point-to-point (9/1.1), and the other is multipoint (9/1.2). Notice how all interfaces that terminate PVCs on a subinterface share the same IP network address. For example, 192.1.1.2, 192.1.1.3, and 192.1.1.4 are the IP addresses on interfaces attached to subinterface 2, which has an IP address of 192.1.1.1.

PVCs on the RPM

In general, a PVC is a static connection between two interfaces on an ATM switch or between two ports on separate switches. A PVC requires an administrative action to establish, typically by a network administrator using a CLI or network management tool. As soon as a PVC is in place, it remains in place unless specifically removed by management action. The switch ports, or the set of resources on the ports that have been allocated to the connection, also remain dedicated for the lifetime of the PVC.

Strictly speaking, a PVC is a static connection in the network. In other words, the connection does not change, regardless of network events or changes. To confuse matters, many Frame Relay and ATM networks use the term PVC to refer to a dynamically routed virtual circuit. The BPX is an example of such a network. On the RPM, two configured elements comprise a PVC: the PVC and the ATM connection. The PVC is associated with a subinterface and is assigned a local identifier, VPI, and VCI. The PVC is often associated with an IP address for Layer 3 routing purposes. An ATM connection links the PVC to a destination endpoint such as another RPM, the PXM1 trunk, or any Frame Relay or ATM port on the MGX switch.

Figure 22-19 shows PVCs and ATM connections on the RPM.

Figure 22-19 PVCs and ATM Connections

RPM connections can terminate on PXM1, FRSM, or AUSM cards, as shown in Figure 22-20.

Figure 22-20 Terminating RPM Connections

Similar to other MGX service modules, ATM connections on the RPM are either master or slave segments. A local connection has a slave connection at one end and a master connection on the other. A feeder connection has a master connection to the PXM1 trunk, a routing connection through the ATM backbone network, and a master connection on the remote MGX switch.

Commands for Configuring Subinterfaces

This section describes the commands you use to create and configure subinterfaces on the RPM ATM switch interface:

• show interface—Displays the status of a specific interface or all interfaces on the RPM.

• interface—Creates or accesses the configuration of an interface or subinterface.

• shutdown—Disables an interface or subinterface. The no shutdown command activates an interface.

• ip address—Assigns an IP address and subnet mask to a subinterface.

Show Interface Command

The show interface command output lists detailed interface and subinterface configuration and status information. You can specify a particular interface. Otherwise, all interfaces are listed.

Here is the show interface command syntax:

show interface [switch <slot-number>/<interface-number>.[subinterface-number]]

The keyword and parameter options are as follows:

• a keyword, all interfaces are listed.

• slot-number—If you specify the switch keyword, you must specify the RPM card slot number.

• interface-number—If you specify the switch keyword, you must specify the interface number. For the RPM switch interface, the only valid value is 1.

• subinterface-number—You can also specify a subinterface number.

For example, type show interface 9/1.100 to list information for subinterface 100 on the ATM switch interface of the RPM in slot 9. Type show interface to list information for all interfaces on the RPM. Example 22-20 shows the show interface switch output for a subinterface.

Example 22-20 show interface switch Output

rpm01>sho int switch 9/1.100

Switch1.100 is up, line protocol is up
 Hardware is ENHANCED ATM PA
 Internet address is 10.100.100.2/24
 MTU 4470 bytes, BW 149760 Kbit, DLY 100 usec,
   reliability 255/255, txload 1/255, rxload 1/255
 Encapsulation ATM
 0 packets input, 0 bytes
 9 packets output,531 bytes
 0 OAM cells input, 0 OAM cells output

Useful information in the show interface switch output includes the following:

• Interface status—Up or down

• Line protocol status—Up or down

• IP address

• Maximum Transmission Size (MTU)—The largest packet size, in bytes, permitted on the interface

• Bandwidth (BW)—The interface bandwidth in kbps

• Encapsulation—Always ATM

• Ingress and egress traffic counters

You can clear the traffic counters by using the clear counters switch command.

Interface Command

The interface global configuration command accesses interface-specific configuration mode. You also use the interface command to create a new subinterface.

When you use the interface command, the CLI prompt changes from hostname(config)# to hostname(config-if)#.

Here is the interface command syntax:

interface [switch <slot-number>/<interface-number>.[subinterface-number]]
  {point-to-point | multipoint | tag}

The keyword and parameter options are as follows:

• switch—This optional keyword shows the switch interface.

• slot-number—If you specify the switch keyword, you must specify the RPM card slot number.

• interface-number—If you specify the switch keyword, you must specify the interface number. For the RPM switch interface, the only valid value is 1.

• subinterface-number—You can also specify a subinterface number.

• point-to-point—Creates a point-to-point subinterface that supports only one PVC. You need to specify this keyword only when you are creating a new subinterface.

• multipoint—Creates a multipoint subinterface that supports multiple PVCs. You need to specify this keyword only when you are creating a new subinterface.

• tag—Creates a tag (MPLS) subinterface. You need to specify this keyword only when you are creating a new subinterface.

Shutdown Command

The shutdown interface-specific configuration command deactivates an interface. Use the no shutdown command to activate an interface. By default, a subinterface is active when you create it using the interface command.

IP Address Command

The ip address interface-specific configuration command is used to assign an IP address to a subinterface.

Here is the ip address command syntax:

ip address <IP-address> <subnet-mask>

The parameter options are as follows:

• IP-address—The IP address assigned to the subinterface. Remember when choosing an IP address that subinterfaces with PVCs between them must be on the same IP network. The IP address is entered in dotted-decimal format, such as 172.100.100.54.

• subnet-mask—The subnet mask used on the subinterface. Subinterfaces with PVCs between them should all be configured with the same subnet mask. The subnet mask is entered in dotted-decimal format, such as 255.255.255.0.

Commands for Creating and Displaying PVCs on the RPM

This section describes the commands you use to create, configure, and display PVCs and connections on the RPM:

• atm pvc—Creates an ATM PVC on an interface

• show atm vc—Displays the status of one or all ATM VCs on the RPM

• map-group—Assigns a map group to an interface

• map list—Creates or accesses the configuration of a map list

• ip—Assigns IP addresses to PVCs in a map list

• show atm map—Lists ATM mapping information

• addcon—Creates a connection between an RPM PVC and the PXM card

• show switch connections—Lists summary or detailed information for the connections on the RPM

ATM PVC Command

The atm pvc interface-specific configuration command adds a new PVC to a subinterface on the RPM. Remember that point-to-point subinterfaces support only one PVC; multipoint subinterfaces support multiple PVCs. You must create a PVC on the subinterface before you can add the ATM connection.

Here is the atm pvc command syntax:

atm pvc <VCD> <VPI> <VCI> <AAL-encapsulation> [inarp]

The keyword and parameter options are as follows:

• VCD—The virtual circuit descriptor is a unique number that identifies the PVC. Do not use VCD 1 or 2 because these are hard-coded for RPM management.

• VPI—The VPI value on the ATM cells created from the IP packets on this PVC. A VPI of 0 indicates that this PVC is a virtual channel connection (VCC). A nonzero value indicates that this is a virtual path connection (VPC). VPCs are used for MPLS edge routing. Remember to restrict VPI values to the range defined by the resource partitions.

• VCI—The VCI value on the ATM cells created from the IP packets on this PVC. Remember to restrict VCI values to the range defined by the resource partitions. Use VCI 0 for VPCs.

• AAL-encapsulation—The encapsulation method used by the RPM. The encapsulation options are aal5snap, used for ATM or translated ATM-Frame Relay services; aal5nlpid, used for transparent ATM-Frame Relay services; and aal5ciscoppp, used for PPP applications—usually frame forwarding connections from the FRSM.

• inarp—Enables inverse Address Resolution Protocol (ARP) updates on aal5snap PVCs.

Show ATM Virtual Circuit Command

The show atm vc command lists summary or detailed information about the virtual circuits (VCs) on the RPM. Use this command to learn which VCs are configured on the RPM and their status.

Here is the show atm vc command syntax:

show atm vc [VCD]

If you type show atm vc, a summary of all VCs is output. If you specify a VCD, detailed information on the specified VC is output. Example 22-21 shows the show atm vc output.

Example 22-21 show atm vc Output

rpm01#sho atm vc

      VCD /                Peak Avg/Min Burst
Interface  Name VPI  VCI Type  Encaps   SC  Kbps  Kbps  Cells Sts
1.1        11    0    11  PVC  SNAP     UBR 155000            UP
1.2        12    0    12  PVC  SNAP     UBR 149760            UP
1.66       66    0    66  PVC  SNAP     UBR 149760            UP
1.100      99    0    99  PVC  SNAP     UBR 149760            UP
1          1     0 65526  PVC  IPC      UBR 149760            UP
1          2     0 65528  PVC  IPC      UBR 149760            UP
1.101      101   6   400  PVC  SNAP     ABR   1200   500      UP
1.101      102   6   401  PVC  SNAP     ABR   1200   500      UP
1.101      400  10     0  PVC  CISCOPPP UBR 149760            UP

The show atm vc output provides the following information:

• The interface or subinterface the VC is on
• The VCD, VPI, and VCI assigned to the VC
• The type of VC—PVC or tag
• The encapsulation method
• The service class
• The configured Peak Cell Rate (PCR)
• The average and minimum traffic rate
• The burst size in cells
• The VC status (UP or DOWN)

Example 22-22 shows the show atm vc output when a VCD is specified.

Example 22-22 show atm vc Output

rpm01#sho atm vc 102

Switch1.101: VCD: 102, VPI: 6, VCI: 401
ABR, PeakRate: 1200, Minimum Rate: 500, Initial Rate: 1200, Current Rate: 0
RIF: 16, RDF: 16
FRM cells received: 0, BRM cells received: 0
RM cells sent: 0
AAL5-LLC/SNAP, etype:0x0, Flags: 0x10820, VCmode: 0x0
OAM frequency: 0 second(s)
InARP frequency: 15 minute(s)
Transmit priority 3
InPkts: 0, OutPkts: 6, InBytes: 0, OutBytes: 168
InPRoc: 0, OutPRoc: 0, Broadcasts: 0
InFast: 0, OutFast: 0, InAS: 0, OutAS: 0
InPktDrops: 0, OutPktDrops: 0
CrcErrors: 0, SarTimeOuts: 0, OverSizedSDUs: 0, LengthViolation: 0,
CPIErrors: 0
Out CLP=1 Pkts: 0
OAM cells received: 0
OAM cells sent: 0
Status: UP

Map Group Command

The map-group interface-specific configuration command identifies a map group for a subinterface. Each multipoint subinterface must refer to a map group name. The associated map list identifies the destination IP addresses for each PVC that terminates on the subinterface. Use the map-list global configuration command to define the map list. Remember that PVCs on a subinterface terminate on interfaces that share the same IP network or subnetwork address.

Here is the map-group command syntax:

map-group <group-name>

group-name is a character string naming the map group. For example, type map-group FRport5 to associate the subinterface with a map group named FRport5.

Map List Command

The map-list global configuration command is used to create a map list and to start map-list-specific configuration mode. When you use the map-list command, the CLI prompt changes from hostname(config)# to hostname(config-map-list)#.

Here is the map-list command syntax:

map-list <list-name>

list-name is the same as the group name specified for the subinterface using the map-group command. For example, type map-list FRport5 to create or access the map list named FRport5.

IP Command

The ip map-list-specific configuration command associates an IP address with a VCD.

Here is the ip command syntax:

ip <IP-address> atm-vc <VCD> [broadcast]

The parameter options are as follows:

• IP-address—The IP address assigned to the VC. Remember when choosing an IP address that subinterfaces with PVCs between them must be on the same IP network. The IP address is entered in dotted-decimal format, such as 172.100.100.54.

• VCD—The VCD of the PVC.

Show ATM Map Command

The show atm map command lists the ATM mapping on the RPM. If you have map lists configured or are using ARP, you will have VCD-to-IP address mapping. Example 22-23 shows the show atm map output.

Example 22-23 show atm map Output

rpm01#show atm map

Map list port101 : PERMANENT
ip 10.10.15.2 maps to VC 101
    , broadcast
ip 10.10.15.3 maps to VC 102
    , broadcast

Add Connection Command

The addcon command adds an ATM connection on the RPM. This connection is similar to a connection on any other service module, such as the FRSM or AUSM. A number of optional parameters are supported for the addcon command. These optional parameters control ATM network routing and are not supported on PXM1 platforms.

Here is the addcon command syntax:

addcon vcc switch <slot-number>/<interface-number>.[subinterface-number]
  <VCI> [rname remote-name] rslot <remote-slot> <remote-interface>
  <remote-VPI> <remote-VCI> [master local]

addcon vpc switch <slot-number>/<interface-number>.[subinterface-number]
  <VPI> [rname remote-name] rslot <remote-slot> <remote-interface>
  <remote-VPI> [master local]

The keyword and parameter options are as follows:

• VCI—The VCI value defined for the ATM PVC. This parameter applies only to VCCs and should match the VCI of the ATM PVC that is already added to the RPM.

• VPI—The VPI value defined for the ATM PVC. This parameter applies only to VPCs and should match the VPI of the ATM PVC that is already added to the RPM.

• remote-name—The node name of the destination MGX switch. For PXM1 MGX switches, all connections terminate on the local switch, so this parameter is not used.

• remote-slot—The destination card slot number. 0 for the PXM1.

• remote-interface—The remote interface (port) number.

• remote-VPI—The remote VPI value on the destination card slot. If the destination service type is ATM, the VPI value can be any number that falls within the configured resource partitions on the destination card. If the destination card is an FRSM, the value is 0.

• remote-VCI—The remote VCI value on the destination card slot. This parameter applies only to VCCs. If the destination card is an FRSM, this parameter is the DLCI at the remote end.

• master local—These optional keywords identify the connection as a master connection. If you do not type master, the connection is a slave. Remember that all feeder connections to the PXM1 must be master connections. If this is a local connection, one end must be the master and the other end the slave. The slave end of the connection (whether on the RPM or a service module) must be added first. Only the master local keyword combination is used. Do not use the master remote keyword combination.

Show Switch Connections Command

The show switch connections command lists summary or detailed information about the connections on the ATM switch interface. Use this command to learn which connections are on the RPM and to learn how they are configured.

Here is the show switch connections command syntax:

show switch connections {vpc | vcc} [VPI] [VCI]

The keyword and parameter options are as follows:

• vpc—Use this keyword to show a specific VPC.

• vcc—Use this keyword to show a specific VCC.

• VPI—The VPI of the VPC you want to show. Use this optional parameter with the vpc keyword.

• VCI—The VCI of the VCC you want to show. Use this optional parameter with the vcc keyword.

Example 22-24 shows the show switch connections output.

Example 22-24 show switch connections Output

rpm01#show switch connections
                                  Synch
lVpi  lVci remoteNodeName  remoteSlot remoteIf rVpi  rVci   Status
  0    11           0             1      10     243        inSynch
 10     0           0             1     200       0        inSynch

Example 22-25 shows the show switch connections output for a specified VCC.

Example 22-25 show switch connections Output

rpm01#show switch connections vcc 11

----------------------------------------------------------
Local Sub-Interface   : 1
Local VPI             : 0
Local VCI             : 11
Remote Node Name      :
Remote Slot           : 0
Remote Interface      : 1
Remote VPI            : 10
Remote VCI            : 243
Routing Priority      : 0
Max Cost              : 255
Restricted Trunk Type : none
Percent Util          : 100
Remote PCR            : 353208
Remote MCR            : 353208
Remote Percent Util   : 100
Connection Master     : Local
Synch Status          : inSynch
Auto Synch            : OFF

Creating Connections on the RPM

Follow these steps to create a connection on the RPM:

You have completed the steps necessary for creating a connection on the RPM.

Summary

This chapter provided an overview of VISM voice features, including voice over AAL2 and IP networks. It showed you how to add, configure, display, and verify voice connections. Voice over ATM on the VISM was discussed, and RPM memory locations were identified.

RPM port numbering was described, and the Cisco IOS CLI was presented. You learned commands for configuring the RPM and commands for setting up the RPM ATM switch interface. This chapter discussed PVCs on the RPM and how to configure subinterfaces. You also saw commands for creating connections and for creating and displaying PVCs on the RPM.

MPLS was introduced, with an outline and discussion of its business and technical advantages. The benefits of label switching were presented, with a discussion of the problems inherent in persistent loops due to network protocol conflicts. Cisco WAN switching products and features with MPLS support were also presented.