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A Network Administrator's View of Multiservice Networks

Chapter Description

Multiservice networks provide more than one distinct communications service type over the same physical infrastructure. Multiservice implies not only the existence of multiple traffic types within the network, but also the ability of a single network to support all of these applications without compromising quality of service (QoS) for any of them. This chapter covers multiservice networks in detail from the network administrator's viewpoint.

Technology Brief—Multiservice Networks

This section provides a brief study on multiservice networks. You can revisit this section frequently as a quick reference for key topics described in this chapter. This section includes the following subsections:

  • Technology Viewpoint—Intended to enhance perspective and provide talking points regarding multiservice Networks.
  • Technology at a Glance—Uses figures and tables to show multiservice networking fundamentals at a glance.
  • Business Drivers, Success Factors, Technology Application, and Service Value at a Glance—Presents charts that suggest business drivers and lists those factors that are largely transparent to the customer and consumer but are fundamental to the success of the provider. Use the charts in this section to see how business drivers are driven through technology selection, product selection, and application deployment in order to provide solution delivery. Additionally, business drivers can be appended with critical success factors, and then driven through the technology, product, and application layers, coupled as necessary with partnering, to produce customer solutions with high service value.

Technology Viewpoint

Multiservice networks are chiefly found in the domain of established service providers that are in the long-standing business of providing traditional voice, TDM leased lines, Frame Relay, ATM, and, more recently, IP communication-networking solutions.

Multiservice networks provide more than one distinct communications service type over a common physical infrastructure. Multiservice implies not only the existence of distinct services within the network, but also the ability of a common network infrastructure to support all of these communication applications natively without compromising QoS for any of them.

The initial definition for multiservice networks was a converged ATM and Frame Relay network supporting these data in addition to circuit-switched voice. Recently, next-generation multiservice networks have emerged, adding Ethernet, Layer 3 IP, VPNs, Internet, and MPLS services to the mix. These next-generation service provider multiservice networks are manifested in the form of technology enhancements to the networking fundamentals of ATM, SONET/SDH, and, since the late 1990s, IP/MPLS.

Characteristically, multiservice networks have a large local and/or long-distance voice constituency: a revenue base that is still projected to make up a large share of provider income in the near term. To protect and enlarge this monetary base will require adept handling of new VoIP transport and service capabilities.

The growing trend in packet telephony adoption is one of the significant new revenue opportunities for service providers. It is important for two reasons. Voice revenue is still projected to make up the primary revenue contribution to multiservice-based providers in the near term. A voice portfolio that meets the value distinctions of the customer base is an absolute business fundamental to engage and collect on these revenue opportunities. Secondly, leading service providers are looking to provide managed voice services as a counter-measure to eroding transport revenues. As traditional circuit-switched voice services and equipment have matured, the resulting commoditization pressures margins into a downward price spiral, as evidenced by the continuous decline in cost per minute and the rise of flat-rate pricing for customary voice services. Service providers need a way to reestablish value in voice offerings, and customer-oriented, managed voice services based on packet telephony is that channel.

Even with the existence of next-generation technology architectures, most providers are not in a position to turn over their core technology in wholesale fashion. Provider technology is often on up-to-decade-long depreciation schedules, and functional life must often parallel this horizon, even if equipment is repurposed and repositioned in the network. Then there is the customer-facing issue of technology service support and migration. Though you might wish to quiesce a particular technology-based offering, the customer is not often in support of your timetable. This requires a deliberate technology migration supporting both heritage services along with the latest feature demands by the market. Since providers cannot recklessly abandon their multiyear technology investments and installed customer service base, gradual migration to next-generation multiservice solutions becomes a key requirement. Next-generation technology evolution is often the result, allowing new networking innovations to overlap established network architectures, bridging and migrating precommitted service delivery to the latest growth markets.

From a global network perspective, the ascendancy of IP traffic has served ATM notice. According to IDC, sales of multiservice ATM-based switches were down 21 percent in 2002, 12 percent in 2003, and another 6 percent in 2004. Both Frame Relay (holding at about 20 percent) and ATM revenues are near plateau, forecasting only modest capacity-driven growth through 2007. Providers with ATM requirements are looking to add MPLS capabilities to their core infrastructures and to push IP features to the edge of the network. Responsible for the development of tag switching, the technology behind the MPLS IETF standard, Cisco Systems has an enviable leadership position in MPLS integration across both ATM and IP networking platforms.

The vast installed base of the Layer 1 SONET/SDH optical infrastructure must also be considered in any measured technology migration. The primary appeal for multiservice provisioning and switching platforms, known in the market as MSPPs and MSSPs, is to consolidate long-established SONET/SDH ADMs in the multiservice metro edge, core, and service POPs, while incorporating new Layer 3 IP capabilities with packet interfaces for Ethernet, Fast Ethernet, and Gigabit Ethernet opportunities. Many contain additional support for multiservice interfaces and DWDM. Deployed as a springboard for the rapid provisioning of multiple services, the intrinsic value in these new-generation multiservice provisioning platforms is to build a bridge from circuit-based transport to packet-based services. Also seen as an edge services platform with which to migrate Frame Relay and other established data services, MSPPs and MSSPs help providers to execute that strategy while maintaining established TDM services and leveraging SONET/SDH capabilities. Entering the market near the end of many legacy SONET/SDH ADM depreciation schedules, the MSPPs inherit a sizable portion of their justification from reduced power, space, and maintenance requirements. In doing so, MSPPs help with continued optimization of operating budgets while representing strategic capital investments for new, high-value IP service opportunity.

Multiservice providers are clearly building IP feature-based networks that have scale. Carriers are moving dramatically to embrace IP/MPLS networks, which combine the best features of Layer 3 routing with Layer 2 switching. MPLS provides the simplicity and feature-rich control of IP routing with the performance and throughput of ATM switching. MPLS allows one to restrict IP processing to the appropriate place—on the edges of the network. IP- and MPLS-based routers can operate at much higher speeds, more economically than can an ATM switch.

Layer 3 MPLS VPNs based on RFC 2547 are at the top of the requirements list for multiservice network providers. MPLS VPN offerings can help enterprise customers transfer complex routing responsibilities to the provider network. This allows providers to increase value for Layer 2 and Layer 3 IP-managed services. These network enhancements will start in-region, and then move to out-of-region when and wherever opportunity dictates. Where regional Bell operating company (RBOC) providers have Section 271 approvals to provide long-distance voice and data, IP/MPLS-based networks will afford the opportunity to compete nationally for data services against North American Inter-eXchange Carriers.

The new era of networking is based on increasing opportunity through service pull, rather than through technology push. Positioning networks to support multiple services, while operationally converging multiple streams of voice, video, and IP-integrated data, is the new direction of multiservice network architecture. In the face of competitive pressures and service substitution, not only are next-generation multiservice networks a fresh direction, they are an imperative passage through which to optimize strategic investment and expense.

Technology at a Glance

Figure 3-17 shows the typical positioning of Cisco multiservice platforms within the MAN architecture.

Figure 17

Figure 3-17 Cisco Multiservice Platforms

Table 3-6 summarizes multiservice technologies.

Table 3-6 Multiservice Technologies

Click to view Table 3-6

Business Drivers, Success Factors, Technology Application, and Service Value at a Glance

Solution and services are the desired output of every technology company. Customers perceive value differently, along a scale of low cost to high value. Providers of solutions and services should understand business drivers, technology, products, and applications to craft offerings that deliver the appropriate value response to a particular customer's value distinction.

The following charts list typical customer business drivers for the subject classification of the network. Following the lower arrow, these business drivers become input to seed technology selection, product selection, and application direction to create solution delivery. Alternatively, from the business drivers, another approach (the upper arrow) considers the provider's critical success factors in conjunction with seed technology, products and their key differentiators, and applications to deliver solutions with high service value to customers and market leadership for providers.

Figure 3-18 charts the business drivers for multiservice networks

Figure 18

Figure 3-18 Multiservice Networks