Home > Articles > Cisco Network Technology > General Networking > I/O Consolidation in the Data Center

I/O Consolidation in the Data Center

  • Sample Chapter is provided courtesy of Cisco Press.
  • Date: Sep 23, 2009.

Chapter Description

This chapter explains the benefits and challenges of designing physical infrastructure to simultaneously carry multiple types of traffic.

Fundamental Technologies

The two technologies that will play a big role in enabling I/O consolidation are PCI-Express and 10 Gigabit Ethernet (10GE).

PCI-Express

Peripheral Component Interconnect (PCI) is an old standard to interconnect peripheral devices to computer that has been around for many years [1].

PCI-Express (PCI-E or PCIe) [2] is a computer expansion card interface format designed to replace PCI, PCI-X, and AGP. It removes one of the limitations that have plagued all these I/O consolidation attempts (i.e., the lack of I/O bandwidth in the server buses), and it is compatible with current operating systems.

PCIe uses point-to-point full duplex serial links called lanes. Each lane contains two pairs of wires: one to send and one to receive. Multiple lanes can be deployed in parallel: 1x means a single lane; 4x means 4 lanes.

In PCIe 1.1, the lanes run at 2.5 Gbps (2 Gbit/s at the datalink), and 16 lanes can be deployed in parallel. This supports speeds from 2 Gbit/s (1x) to 32 Gbit/s (16x). Due to protocol overhead 8x is required to support a 10GE interface.

PCIe 2.0 (i.e., PCIe Gen 2) doubled the bandwidth per lane from 2 Gbit/s to 4 Gbit/s and extended the maximum number of lanes to 32x. It is shipping now.

PCIe 3.0 will approximatively double the bandwidth again: "The final PCIe 3.0 specifications, including form factor specification updates, may be available by late 2009, and could be seen in products starting in 2010 and beyond." [3].

10 Gigabit Ethernet

10GE is a practical interconnection technology since 2008. The standard has reached the maturity status and cheap cabling solutions are available. Fiber continues to be used for longer distances, but copper is deployed in the Data Center for its lower cost.

Switches and CNAs have standardized their connectivity using the Small Form-factor Pluggable (SFP) transceiver. SFPs are used to interface a network device motherboard (i.e., switches, routers, or CNAs) to a fiber optic or copper cable. SFP is a popular industry format supported by several component vendors. It has expanded to become SFP+, which supports data rates up to 10 Gbit/s [9]. Applications of SFP+ include 8GFC and 10GE.

The key benefits of SFP+ are:

  • A comparable panel density as SFP
  • A lower module power than XENPAK, X2, and XFP
  • A Nominal 1W power consumption (optional 1.5W high power module)
  • Backward compatibility with SFP optical modules

The IEEE standard for twisted pair cabling (10GBASE-T) is not yet a practical interconnection technology, because it requires an enormous number of transistors, especially when the distance grows toward 100 meters (328 feet). This translates to significant power requirements and into additional delay (see Figure 1-4). Imagine trying to cool a switch linecard that has 48 10GBASE-T ports on the front-panel, each consuming 4 watts!

Figure 1-4

Figure 1-4 Evolution of Ethernet Physical Media

A more practical solution in the Data Center, at the rack level, is to use SFP+ with copper Twinax cable (defined in SFF-8431, see [9]). The cable is flexible, approximately 6 mm (1/4 of an inch) in diameter, and it uses the SFP+ themselves as the connectors. Cost is limited; power consumption and delay are negligible. It is limited to 10 meters (33 feet) that are sufficient to connect a few racks of servers to a common top of the rack switch.

These cables are available from Cisco, Amphenol, Molex, Panduit, and others.

Figure 1-5 illustrates the advantages of using Twinax cable inside a rack or few racks.

Figure 1-5

Figure 1-5 Twinax Copper Cable

The cost of the transmission media is only one of the factors that need to be addressed to manufacture 10GE ports that are cost competitive. Other factors are the size of the switch buffers, and Layer 2 versus Layer 3/4 functionality.

6. Additional Requirements | Next Section Previous Section

Cisco Press Promotional Mailings & Special Offers

I would like to receive exclusive offers and hear about products from Cisco Press and its family of brands. I can unsubscribe at any time.

Overview

Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about Cisco Press products and services that can be purchased through this site.

This privacy notice provides an overview of our commitment to privacy and describes how we collect, protect, use and share personal information collected through this site. Please note that other Pearson websites and online products and services have their own separate privacy policies.

Collection and Use of Information

To conduct business and deliver products and services, Pearson collects and uses personal information in several ways in connection with this site, including:

Questions and Inquiries

For inquiries and questions, we collect the inquiry or question, together with name, contact details (email address, phone number and mailing address) and any other additional information voluntarily submitted to us through a Contact Us form or an email. We use this information to address the inquiry and respond to the question.

Online Store

For orders and purchases placed through our online store on this site, we collect order details, name, institution name and address (if applicable), email address, phone number, shipping and billing addresses, credit/debit card information, shipping options and any instructions. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.

Surveys

Pearson may offer opportunities to provide feedback or participate in surveys, including surveys evaluating Pearson products, services or sites. Participation is voluntary. Pearson collects information requested in the survey questions and uses the information to evaluate, support, maintain and improve products, services or sites; develop new products and services; conduct educational research; and for other purposes specified in the survey.

Contests and Drawings

Occasionally, we may sponsor a contest or drawing. Participation is optional. Pearson collects name, contact information and other information specified on the entry form for the contest or drawing to conduct the contest or drawing. Pearson may collect additional personal information from the winners of a contest or drawing in order to award the prize and for tax reporting purposes, as required by law.

Newsletters

If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email information@ciscopress.com.

Service Announcements

On rare occasions it is necessary to send out a strictly service related announcement. For instance, if our service is temporarily suspended for maintenance we might send users an email. Generally, users may not opt-out of these communications, though they can deactivate their account information. However, these communications are not promotional in nature.

Customer Service

We communicate with users on a regular basis to provide requested services and in regard to issues relating to their account we reply via email or phone in accordance with the users' wishes when a user submits their information through our Contact Us form.

Other Collection and Use of Information

Application and System Logs

Pearson automatically collects log data to help ensure the delivery, availability and security of this site. Log data may include technical information about how a user or visitor connected to this site, such as browser type, type of computer/device, operating system, internet service provider and IP address. We use this information for support purposes and to monitor the health of the site, identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents and appropriately scale computing resources.

Web Analytics

Pearson may use third party web trend analytical services, including Google Analytics, to collect visitor information, such as IP addresses, browser types, referring pages, pages visited and time spent on a particular site. While these analytical services collect and report information on an anonymous basis, they may use cookies to gather web trend information. The information gathered may enable Pearson (but not the third party web trend services) to link information with application and system log data. Pearson uses this information for system administration and to identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents, appropriately scale computing resources and otherwise support and deliver this site and its services.

Cookies and Related Technologies

This site uses cookies and similar technologies to personalize content, measure traffic patterns, control security, track use and access of information on this site, and provide interest-based messages and advertising. Users can manage and block the use of cookies through their browser. Disabling or blocking certain cookies may limit the functionality of this site.

Do Not Track

This site currently does not respond to Do Not Track signals.

Security

Pearson uses appropriate physical, administrative and technical security measures to protect personal information from unauthorized access, use and disclosure.

Children

This site is not directed to children under the age of 13.

Marketing

Pearson may send or direct marketing communications to users, provided that

  • Pearson will not use personal information collected or processed as a K-12 school service provider for the purpose of directed or targeted advertising.
  • Such marketing is consistent with applicable law and Pearson's legal obligations.
  • Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
  • Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

Correcting/Updating Personal Information

If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at customer-service@informit.com and we will process the deletion of a user's account.

Choice/Opt-out

Users can always make an informed choice as to whether they should proceed with certain services offered by Cisco Press. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive: www.ciscopress.com/u.aspx.

Sale of Personal Information

Pearson does not rent or sell personal information in exchange for any payment of money.

While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to NevadaDesignatedRequest@pearson.com.

Supplemental Privacy Statement for California Residents

California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

Sharing and Disclosure

Pearson may disclose personal information, as follows:

  • As required by law.
  • With the consent of the individual (or their parent, if the individual is a minor)
  • In response to a subpoena, court order or legal process, to the extent permitted or required by law
  • To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
  • In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
  • To investigate or address actual or suspected fraud or other illegal activities
  • To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
  • To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
  • To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.

Links

This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

Requests and Contact

Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

Changes to this Privacy Notice

We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

Last Update: November 17, 2020