Book Excerpt: Next-Generation Network Services

In this excerpt from a Cisco Press tome, we provide fundamental technical information about Ethernet technology.

by Robert Wood in Next-Generation Network Services, published by Cisco Press [May 11, 2006]

This is excerpt is from Chapter 8: Wireline Networks, pp. 503-509 of Next-Generation Network Services, published by Cisco Press

Ethernet to the Masses
Who wouldn't want IP everywhere? For that matter, who wouldn't want Ethernet everywhere? All Internet-based traffic today begins and ends with IP transported over Ethernet. Indeed, mass-market connectivity to the Internet will continue to march toward the Ethernet connectivity model.

Enterprise networks have long been the fertile grazing grounds for LAN technology. Ethernet, Fast Ethernet, and Gigabit Ethernet are popular technologies for linking desktop and laptop PCs, VoIP telephones, and wireless access points to corporate data servers and even IBM mainframes. As personal computer manufacturers increasingly integrate Fast Ethernet into standard PC technology, Ethernet has leapt from the enterprise into the home networking market. Both cable and DSL providers interface their respective modem technologies with the subscriber's PCs, primarily via Ethernet. With millions of Ethernet ports in both the business and home markets, today's service providers are surrounded with requirements for price-performing Ethernet transport and service options.

Traditional TDM-based T1s, DSL, and cable cannot touch the bandwidth opportunities afforded by 10/100/1000 Mbps Ethernet. There are just too many equipment types with too many protocols. Subscribers, whether business or residential, use networks capable of supporting megabits of bandwidth. Wireline providers have core networks that support gigabits of bandwidth. The bottleneck between the two is more apparent than ever before.

Fast Ethernet, Gigabit Ethernet, and 10 Gigabit Ethernet are all based on the original Ethernet technology that dominates the LAN environment. Today, the largest percentage of the data traffic in the metropolitan area terminates on LANs. Therefore, because most LANs are predominately Ethernet, the most obvious solution is to use Ethernet as the end-to-end Layer 2 technology in order to flatten the protocol stack between the provider and the Ethernet user, minimizing protocol conversions and MAC rewrites wherever possible.

For Ethernet to scale in speed and ubiquity, it requires the guaranteed QoS, and operations, administration, and maintenance (OAM) features that are needed for provider-grade voice, audio, and video applications of sub-50-millisecond (ms) recovery time and approximately 99.999 percent network availability. And it must do this over a number of massively large customer market segments for Ethernet transport services.

Ethernet options for wireline providers take several forms. In Chapter 5, "Optical Networking Technologies," you learned about the optical Ethernet solutions of Ethernet over SONET/SDH, Ethernet over RPR/DPT, Ethernet over MPLS, and other Ethernet transport technologies. The demand for provider Ethernet services will encompass transparent LAN services, Ethernet private line services, Ethernet-to-Internet services, and Ethernet over passive optical networks (EPONs). Wireline providers in all segments are pursuing and deploying many of these metro Ethernet solutions.

This new opportunity for Ethernet to the masses is predicated on

• Bandwidth scalability—An Ethernet interface is a low-cost access interface, yet one that can be used to scale bandwidth from 10 Mbps to 100 Mbps and even up to 1 Gbps without changing the customer premise equipment interface.
• Bandwidth granularity—Most of the contemporary Ethernet switching equipment is QoS enabled and can be provisioned to provide very granular, tiered, bandwidth options; this has great appeal to customers who like to purchase what they need, when they need it.
• Rapid provisioning—Provisioning Ethernet is largely based on software parameters to increase or decrease bandwidth and add new services. Packet provisioning is faster since network equipment and subscriber interfaces don't change. Services can be provisioned in days or even hours, rather than weeks.
• Global interoperability—Users desire technology to be simple, fast, inexpensive, and largely transparent. They desire the ability to compute and communicate from a number of different locations. Ethernet has all of the attributes to approach global interoperability by providers everywhere.

Ethernet to the masses is best enabled through international standards that define markets, requirements, technology options, and management. Standards help with investment protection, interoperability, and scalability of technology and platforms. A global standard is available for delivering Ethernet to the masses.

The IEEE 802.3ah standard for Ethernet in the First Mile was ratified in June of 2004. The term "in the First Mile" is not explicit to an exact distance, but more representative of the local loop access link between a subscriber and the provider's nearest point of presence. Further, "First Mile" emphasizes the technology from the customer's perspective. The IEEE 802.3ah (EFM) standard identifies the following areas for Ethernet delivery in the access layer:

• Ethernet in the First Mile over Copper (EFMC)
• Ethernet in the First Mile over Point-to-Point Fiber (EFMF)
• Ethernet in the First Mile over Passive Optical Network (EFMP or EFM EPON)
• Ethernet in the First Mile Operations, Administration, and Maintenance (EFM OAM)

Figure 8-12 shows a summary of developing Ethernet-based services.

Figure 8-12 Ethernet-Based Services

Source: Cisco Systems, Inc.

Reproduced from the book Next-Generation Network Services. Copyright 2006, Cisco Systems, Inc.. Reproduced by permission of Pearson Education, Inc., 800 East 96th Street, Indianapolis, IN 46240.

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