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Engineering & Design: An ethernet evolution

THE RATIFICATION OF 10-GIGE IN 2001 HAS BEEN A MAJOR BOOST FOR ROBERT METCALFE'S CREATION. IT ALSO HAS THE POTENTIAL TO CHANGE THE NETWORKING LANDSCAPE.Ethernet has evolved far beyond its creator, Rob...


March 1, 2003  


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THE RATIFICATION OF 10-GIGE IN 2001 HAS BEEN A MAJOR BOOST FOR ROBERT METCALFE’S CREATION. IT ALSO HAS THE POTENTIAL TO CHANGE THE NETWORKING LANDSCAPE.

Ethernet has evolved far beyond its creator, Robert Metcalfe’s dreams. Today, virtually all traffic on the Internet starts and ends with an Ethernet connection. E-business could not exist without it.

Undoubtedly, Gigabit Ethernet is the industry standard for corporate networks all over the world. With 10-Gigabit Ethernet (10-GigE) ratified, we can only expect the evolution of Ethernet to continue.

In the summer of 2001, IEEE ratified the 10GigE standard or 802.3ae specification[JD1]. Early adopters, including research and government institutions, are now beginning to reap the benefits of this technology.

The global adoption of this technology by corporations will enable them to better manage the continuous growth of enterprise applications. In addition, carriers and service providers can now cost effectively supply customers with faster services.

Since the ratification the market has seen an influx in 10-GigE technology for the LAN. But many network managers have yet to maximize its potential. As a result, we can expect increased market of activity from the latent adopters of technology equipment, followed by a price drop over the next few years.

Additionally, it promises to dramatically expand the applications for Ethernet beyond LANs into metropolitan-area networks (MAN) and wide-area networks (WAN).

With 10-GigE, enterprise and carrier networks around the world will have the opportunity to send data at the line rate without worrying about different protocols.

10-GIGE IN THE LAN

The development and standardization of 10GigE technology has been driven by a number of applications on the enterprise LAN, such as CRM, data warehousing, and ERP as well as everyday tasks such as file transfers and e-mail that require more and more speed.

Although there are opportunities in the MAN and WAN, the LAN will still be the biggest home for 10-GigE.

To meet the growing needs for performance and availability, the network manager adds additional servers, runs each application on a separate server or across multiple servers, and increases server performance with multiple processors and gigabit links.

As the network scales, network managers may add a server aggregation layer between the servers and the core switch.

To increase resilience, they often use dual redundant links to connect each server to a pair of server aggregation switches, which are then connected to the core switch via redundant trunked gigabit links.

Providing increased performance in the uplink from the server aggregation layer to the core switch is a key application for 10-GigE. High-performance enterprise servers can now saturate a gigabit link.

As the number and performance requirements of the servers connected to the server aggregation layer increases, so does the need for a high-performance uplink.

In the majority of deployments, the server aggregation switches are located in the data center close to the core switch.

The network manager can choose to create the link using a 10GBase-LX4 transceiver with multimode cable or 10GBase-LR with single mode cable, both of which are easily capable of supporting the distance and bandwidth requirements.

Pricing, however, will keep enterprises from adopting 10 GigE widely in 2003. Deployment will probably be limited to Fortune 100 companies and research education facilities.

Once pricing drops, expect 10 GigE to become a standard among enterprises.

The global adoption of this technology by corporations will enable them to better manage the continuous growth of enterprise applications.

10-GIGE IN THE MAN

Ethernet has slowly been penetrating the networks of telecommunications service providers. Gigabit Ethernet is playing a defining role in bringing broadband services to data-deprived metropolitan networks. And we can expect no different from the new 10-GigE standard.

An emerging group of vendors are offering bandwidth services that are beginning to break the local loop bottleneck by utilizing native Ethernet technology over fiber and copper, and offering bandwidth at speeds of up to 1 Gbps.

These Gigabit Ethernet providers are offering bandwidth to enterprise customers at prices dramatically lower than traditional SONET/Asynchronous Transfer Mode (ATM) connections.

A significant shift toward faster data communications networks is helping to drive this market as the demand for bandwidth-intensive services grows.

10GigE is the next step up in performance, and is appearing as an aggregation technology in the core of metropolitan networks.

The 10GBASE-ER standard provides a 10GigE connection over single mode cable at a distance of up to 40 kilometres. This enables metropolitan network operators to scale performance without the need to terminate and utilize additional fiber connections.

The key benefits of Ethernet over traditional ATM and SONET/SDH in metro applications are cost, convenience, and service:

Cost – With its roots in the LAN, Ethernet technology has advantages over current local loop technologies such as SONET/SDH and ATM, lowering its per-port costs through more cost effective equipment and packet overhead savings. It is important to note that SONET/SDH was designed as a technology for carrying voice traffic, while Ethernet was initially designed to carry data traffic.

The major advantage of Ethernet is flexibility and the promise of dynamic bandwidth. Traditionally with SONET, as a customer’s bandwidth demands increase over time, increased bandwidth must be purchased in large increments at fixed prices whether the bandwidth is fully used or not.

Convenience – Gigabit Ethernet providers can provision bandwidth in a matter of days, wiring multi-tenant units (MTUs) or other customer premises in a fraction of the time necessary for an incumbent local exchange carrier (ILEC).

Providers can also add additional bandwidth for a customer in hours or days simply by upgrading software. Services are offered through the standard RJ-45 port within the customer premises, allowing for a single Ethernet handoff from the customer to the provider.

Services – Gigabit Ethernet providers will offer a suite of new services outside the range of traditional data transport services. Services may include regional Ethernet-to-Ethernet connectivity, high-speed Internet access, and multimedia applications such as real-time video and Voice-over-IP (VoIP).

In MANs, many carriers taking advantage of the price/ performance of Ethernet and 10-GigE to provide cost-effective, scalable services.

When a customer signs on to a 10-GigE MAN, the most noticeable benefits are price, comparable bandwidth on SONET/ATM, faster Internet access, and adjustable bandwidth.

10-GIGE IN THE WAN

While Ethernet has become the dominant technology in the LAN and has some significant benefits for transferring data traffic efficiently, SONET/SDH is used extensively in the WAN and will continue to be popular for some time.

Packet over SONET/SDH has built-in management capabilities, which are essential for transporting data over very long distances.

If something fails, there has to be a mechanism for informing the network manager. Ethernet was never designed for these distances, so its management capabilities are much less established.

Much of Ethernet’s success has been based on its low cost and simplicity. Equipment vendors are saying that Ethernet in the WAN may cost 80 per cent less than SONET/SDH and 90 per cent less than ATM.

These numbers attracted so much interest that the IEEE P802.3ae Task Force has developed a standard to provide support for WAN connections.

The standard allows WAN and LAN convergence. 10-GigE equipment manufacturers have added logic to the physical layer to convert the traffic to SONET/SDH rates.

That is, the physical layer will clock traffic into the LAN at 10 Gbps, but it will clock it out into the WAN at 9.584640 Gbps. Because the logic is relatively simple, adding it is not expected to have si
gnificant impact on the cost of Ethernet in the WAN.

With the proliferation of voice, video and data communication, WANs are being asked to handle more data than ever before.

Because Ethernet switches are less expensive than their SONET/ATM counterparts, service providers can offer less expensive services. Ethernet is destined to become the new “hot” choice for start-up carriers.

Its ability to support existing and future installations will help ensure that LAN, WAN and MAN networks can expand easily when needed. The technology presents an opportunity to scale the performance of network cores to meet the increasing demands of users and applications.

And with the addition of 10-GigE, Ethernet continues to have endless possibilities for growing networks.

Nick Tidd is managing director of 3Com Canada. 3Com has been actively involved in the development of the IEEE 802.3ae 10-GigE standard since its inception in March 1999.


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