Could WAN Ethernet replace SONET and ATM?
Metro Ethernet Forum leader Nan Chen thinks so - unsurprisingly enough.
By Bryan Betts, Techworld | Published: 01:00, 29 March 2005
Organisations could soon be running seamless end to end Ethernet, even across the WAN, between offices in different countries, and into the homes of teleworking employees. So claims Nan Chen, president of the Metro Ethernet Forum (MEF) and marketing VP at equipment supplier Atrica.
From its starting point developing Ethernet standards for carriers to implement in metropolitan area networks (MANs), the MEF recently took on the work of the Ethernet First Mile Alliance too. The EFMA has focused on the needs of telcos trying to compete with cable TV companies in so called 'triple-play' services - providing consumers with voice, data and video services.
Chen says that although the markets for corporate MANs and home TV or video-on-demand are different, there is also a lot of similarity between the two. The EFMA was developing standards for Ethernet in the local loop (IEEE 802.3ah), while MEF worked on standards for Ethernet in carrier networks, but their aim was the same - to create a homogeneous network.
So what would metro Ethernet look like? Chen says it could use the same fibres as today, the difference would simply be the protocol on top, and of course the card in the router. He points out though that most routers will already have Ethernet anyway, and says that some applications - a private network connecting multiple sites via an any-to-any Layer 2 VPN, say - might not need routers at all.
"It's Ethernet plus five carrier attributes - re-routing protection to guarantee latency, service management, TDM emulation for PBX traffic," he says. "It's also scaleability and hard SLAs - guaranteed bandwidth on Ethernet has never been done before.
"Today, the transport layer is mostly focused on ATM and SONET. As traffic becomes more packet-based, it's better to have a packet-friendly transport. Encapsulation works, but the question is efficiency and bandwidth - Ethernet is much more scaleable."
Chen cites a survey of Ethernet early-adopters, carried out in North America and Europe by market researcher RHK. He says this showed that large corporate users are concerned by rising bandwidth needs
"Bandwidth growth is going to outgrow the existing infrastructure," he says. "Metro Ethernet will use fibres more efficiently and give more bandwidth, for example SONET is 2.5Gbit, Ethernet could be 10Gbit or more on the same fibre. People are offering 20Mbit per subscriber for triple-play."
According to the survey, Ethernet services enable new business practices and dynamic methods of operation, Chen says: "For carriers, it's economics - you can provide more services on your infrastructure, so a telco can compete with cable companies. Large customers could also run their own carrier network over dark fibre, but it's probably more cost-effective to use a managed service."
According to the RHK study, the benefits seen by corporate early adopters include a lower cost per Mbit, the ability to consolidate servers and support enterprise applications, and IT productivity savings as a result of reallocating resources from network management to service upgrades and other business-oriented issues.
The surprise, Chen adds, was that they did not see additional hardware cost as a significant issue. "Ethernet could be a means to reduce overall IT costs, as part of the consolidation trend," he says. "90 percent say they are willing to pay a premium for metro Ethernet in order to save elsewhere."
Could metro Ethernet benefit your organisation, or will you be sticking with your existing WAN? Add your comments in our forum.