10.5 Conclusion

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There are dozens of providers operating nationwide data backbone networks. Many of them offer ATM, frame relay, or IP services, giving customers the opportunity to take advantage of the most appropriate technology or easily migrate between them as their needs change, without having to deal with multiple service providers and equipment vendors. Some of these carriers have fiber networks in major metropolitan areas that are built on SONET or WDM technologies and which offer Ethernet services as well. Now that the latest generation of IMA systems supports all of these traffic types, there is not even the need for customers to add or change CPE to take advantage of any or all of these technologies.

Some vendors and service providers consider Ethernet as a high-speed packet network, especially since the emergence of Gigabit Ethernet. The initial applications for Gigabit Ethernet were for campuses or buildings requiring greater bandwidth between routers, switches, hubs and repeaters, and servers. Examples include switch-to-router, switch-to-switch, switch-to-server, and repeater-to-switch links. Today, Gigabit Ethernet switches are using better-quality electro-optics that can light up the fiber for 40 km, greatly exceeding the distance limitations of the original standards. And with optical-electrical-optical (OEO) regenerators, distances can be extended to a couple hundred kilometers (124 miles).

The specification for Ethernet at the SONET OC-192 rate of 10 Gbps was ratified by the IEEE in mid-2002. This flavor of Ethernet uses the IEEE 802.3 Ethernet MAC protocol, frame format, and frame size. Because 10-Gigabit Ethernet is still Ethernet, it minimizes the IT department’s learning curve by allowing use of the same management tools. If procured as a service, users can self-provision bandwidth using a browser to meet bandwidth needs that start at 1 Mbps and scale to 1 Gbps or more. Once the fiber is installed to the customer premises, the customer can directly provision the service. This is in considerable contrast to provisioning T3 or OC-3 connections, which entail lead times from incumbent carriers that can range from 45 to 120 days.

Ethernet will continue to scale. Some carriers have implemented the 40-Gbps draft specification, which uses SONET’s OC-768. Proprietary switches are available that support Ethernet at 100 Gbps, but the industry may lean toward 40-Gigabit Ethernet, since the pipes exist today in the form of OC-768 and there is proven technology to build off of that, whereas there is no specification yet for 100 Gbps.



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LANs to WANs(c) The Complete Management Guide
LANs to WANs: The Complete Management Guide
ISBN: 1580535720
EAN: 2147483647
Year: 2003
Pages: 184

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