High-bandwidth functions move closer to reality for wide area corporate networks

For Metro Ethernet to succeed, the industry needs to prove the technology can work alongside the existing internet...

metropolitan ethernet For Metro Ethernet to succeed, the industry needs to prove the technology can work alongside the existing internet infrastructure. A major breakthrough came at the Supercomm 2003 trade show, where suppliers showed how their equipment could work together to provide a network for IP applications. Broadband-Testing Labs' Steve Broadhead reports

Metro Ethernet is the technology that can - and, according to analysts, will - bring real broadband connectivity directly to the office or home, delivered across fibre cable into metropolitan areas.

It could be argued that 2mbps ADSL and similar cable options are not true broadband technologies, when Metro Ethernet suppliers talk of 10mbps basic Ethernet bandwidth (the maximum that ADSL offers) being a bare minimum. They say genuine 100mbps and even Gigabit Ethernet internet/metropolitan area network access is on the cards with a Metro Ethernet installation, at which point services such as high-resolution video broadcasts can become a reality.

Of course, 1mbps internet access is broader than 56kbps dial-up modem or 64kbps ISDN access, but true Ethernet access speeds would move the internet world into a new dimension.

The idea of a ubiquitous Ethernet global network has been on the cards since Asynchronous Transfer Mode lost out to Gigabit Ethernet in the Lan arena. So the idea is not new, even if we are still some way - perhaps 12 months or more - from a finalised Metro Ethernet solution being available. But analysts such as Michael Howard, co-founder of Infonetics Research in the US, are getting excited about its chances in the wide area network.

"In the next 10 years, Ethernet will inexorably take over the metro," said Howard.

"Between 2002 and 2006, Ethernet will make major inroads into metro telecom equipment spending, accumulating $18bn [£11.9bn]."

This spending is being driven by the fact that more users are demanding Ethernet services, lower prices and the convenience of incremental bandwidth from their service providers. In the wide area, companies such as Neos Networks, Fibernet and Exponential-E have begun to make inroads into the classic BT-esque leased-line business with pure Ethernet Wan connections that require nothing more than the availability of a spare Ethernet port on the office router in order to be deployed.

The key elements that will drive the success of Metro Ethernet are high available bandwidth and simplicity of deployment and management of the technology. In the DSL world, Net to Net Technologies (see box on p40) has had significant success against ATM-based solutions for these very reasons.

But at the global level Metro Ethernet aspires to, there is a very significant barrier to overcome - a wall of SDH/Sonet (Synchronous Digital Hierarchy/Synchronous Optical Network) and DWDM (Dense Wave Division Multiplexing) installations put in place by all the major telcos over the past few years at great expense. These are the technologies (Sonet in the US, SDH in Europe) used to create the global internet backbones, along with ATM, that we all use on a daily basis.

From a financial standpoint, there is no way these layers of technology are going to be stripped away and abandoned. Moreover, this technology - designed to run high levels of traffic over fibre globally - does a very real and important job.

But providing a wide range of low-cost, high-bandwidth services in metropolitan areas was never on the SDH/Sonet agenda. What, then, is the answer?

Quite simply, the worlds of SDH/Sonet/DWDM and Metro Ethernet must integrate, rather than collide, in order for the latter to be a realistic proposition, commercially and financially.

The Metro Ethernet interoperability demonstration at the Supercomm 2003 trade show in the US did much to reiterate this belief. This was the largest and most comprehensive service interoperability demonstration of Metro Ethernet services to date - and the first time the general public has been able to see a genuine multi-supplier solution running real applications.


The demonstration was not simply about Metro Ethernet but was heavily geared towards the integration of Ethernet and SDH/ Sonet/DWDM technologies. In total, 28 Metro Ethernet Forum (MEF) members took part in creating an end-to-end Metro Ethernet network that included Ethernet over SDH/Sonet and even SDH/Sonet over Ethernet to show that you can "pick 'n' mix" your way around these technologies and still get a working solution. Beyond this basic interoperability, the aim of the demonstration was to show that real applications will run across these hybrid technology networks.

Demonstrations were concerned with compatibility across two types of network service, called E-Line and E-Lan. E-Line provides a point-to-point Ethernet Virtual Connection (EVC) between two UNIs (subscribers). The E-Line Service is used for Ethernet point-to-point connections. E-Lan provides multi-point connectivity ie, it may connect two or more UNIs.

From a subscriber standpoint, an E-Lan Service makes the Metro Ethernet network look like a Lan, which brings us back to the classic "giant Lan" argument - the one that everyone has wanted since they could spell the word Ethernet.

Using E-Line and E-Lan, members of the MEF showed a number of discrete applications running between different suppliers' booths across a core Metro Ethernet network, simulating a real-world installation. The demonstration was built around a 10 Gigabit Ethernet core based on Cisco and Extreme Networks switch technology. Supporting this were a number of Ethernet aggregation and access devices connecting a variety of hosts running applications that varied from webcam-enabled instant messaging to IP telephony and video streaming over Ethernet point-to-point and point-to-multipoint services.

These connections were running at up to 100mbps or even at 1gbps, showing the kind of real broadband access that is not currently available in the office or home.

Each of the end-to-end services and applications were established on dedicated virtual Lans in order to make them truly controllable and manageable - again simulating a real-world installation. Test "traffic" was also being created to verify service level agreement parameters by generating traffic, validating the service between source and destination, service integrity and measuring loss, latency and jitter performance to ensure that the technical requirements were being met. All results proved positive, showing that the Metro Ethernet installation was capable of supporting defined SLAs and meeting the delivery requirements set, as a customer would demand in a real situation.

Interoperability was key here, since the kind of large-scale, end-to-end network a user is likely to encounter when transparently using Metro Ethernet technology is equally likely to contain equipment from multiple suppliers. For this reason, the Supercomm demonstration requirements were very strict when it came to ensuring interoperability.

Each of the participants had to provide three point-to-point services supporting webcam-enabled Netmeeting sessions, one E-Lan service in the form of an MPeg video stream broadcast to each of three groups of seven or eight suppliers and an optional global E-Lan service set of four applications: global video streaming, Yahoo Instant Messaging, theatre webcam and IP telephony across the entire network.

Looking beyond the Supercomm demonstration and the current MEF members, it is clear that most networking suppliers are looking to get into the Metro Ethernet market as soon as poss-ible, which shows that the industry believes Ethernet is moving into the areas previously reserved for other technologies.

Lan-oriented switch suppliers such as Foundry Networks - itself shortly to become an MEF member - are investing heavily in Metro Ethernet products. Similarly, Hitachi - a company traditionally involved in storage and mainframe technology - has also entered the Metro Ethernet market. This broad range of market entries is a healthy sign for the future of the technology, as it is not being dominated by any one supplier or market sector.

Closely related to the MEF is the Ethernet in the First Mile Alliance (EFMA) which has the task of establishing Ethernet as the technology of choice for the first/last mile of network to feed residential and office users directly, working hand-in-hand with Metro Ethernet feeds.

In order to offer Ethernet services over legacy transport, carriers must wrestle with a variety of technical and operational challenges, according to Craig Easley, chairman of the EFMA. "The Metro Ethernet service definitions will help to promote the consistent delivery of Ethernet services over a variety of transport media," he said.

The technology is designed to run over copper or fibre cable meaning that, in this case, relatively low-speed Ethernet copper wire-based DSL-type deployments are supported, as are higher-speed alternatives over copper and fibre. Again, the key element is simplicity and ease of management, with the aim of drastically reducing the cost of deploying metropolitan broadband access.

Companies such as Metrobility are looking to enable service providers to deliver what, in theory, are complex, high-bandwidth, metropolitan services with as close to a plug-and-play delivery mechanism as is possible. This approach is leagues away from the ATM-oriented approach of DSL that we have seen to date, where configuration and deployment are relatively complex, expensive and time-consuming.

Timescales are still uncertain, but it looks as if the Ethernet will become truly ubiquitous over the next few years - it already is in countries such as Korea, where government funding has allowed the mass delivery of broadband internet access into homes, with Ethernet a key enabling technology.

This can only be good news for the user as it simplifies their world of IT and should mean more bandwidth for less money.

A full report on the current state of Metro Ethernet, "Metro Ethernet - A Snapshot" will be available shortly from the Broadband-Testing website


What is Metro Ethernet?

Ethernet is the most widely used method of accessing local area networks. In metropolitan area networks, it has the potential to increase network capacity cost-effectively and offer a range of services in a simple, scalable and flexible manner.

In enterprise networks, this "Metro Ethernet" is used primarily for connecting to the internet and connecting geographically separate sites - an application that extends the reach and functionality of corporate networks.

More information

' www.metroethernetforum.org/MEFTechOverviewWhitePaper071102.pdf

A current alternative: Ethernet over DSL   

Recently we had a pure Ethernet-based DSL solution (DSlams and CPE) from Net To Net Technologies in the Broadband-Testing Labs and were very impressed with its ease and speed of setting up and overall performance. 

While, historically, all "mainstream" xDSL DSLam solutions have been ATM-based, Net To Net opted for a pure Ethernet approach from day one. ATM proponents argue that Ethernet lacks the required scalability. Net To Net counters that by pointing to the same arguments being used against Gigabit Ethernet - and look where that technology is now.  

More importantly, the company argues that the simplicity of the Ethernet solution brings deployment and management costs down significantly. The key point here is speed of return on investment for the service provider or user enterprise deployment.  

In Europe, service providers have often blamed the cost of provisioning the service and the inherent management costs thereafter for the lack of resulting revenue. The basic cost of entry for an Ethernet-based solution is also significantly lower, though obviously this levels out more as port density increases through economies of scale. 

We also put the features to the test with a video over DSL trial and it ran extremely well. With ADSL now running at up to 10.5mbps downlink speed and Net To Net offering a 9.2mbps SDSL (symmetrical bandwidth) solution, the Ethernet-based DSL route is certainly an option worthy of consideration and will work alongside Metro Ethernet deployments as they become more widespread, due to simple Ethernet compatibility.

Key contributors to the Supercomm Metro Ethernet demonstration   

Atrica  SLA conformance and network management  Cisco Systems  Multi-technology (Ethernet, Sonet, CWDM, Wireless) interoperability  Corrigent  Sonet/SDH, RPR, MPLS and Ethernet interoperability  Ensemble  Wireless Metro Ethernet and legacy TDM service support  Extreme Networks  Core Ethernet switching at 10gbps and multi-application wired/wireless support  Tpack  E-Line and E-Lan services as an integrated solution over SDH/Sonet via virtual Ethernet switches  Internet Photonics  "Free" additional bandwidth for Ethernet services over Sonet/SDH  JDS Uniphase  Interoperability between CWDM/DWDM and Metro Ethernet  Native Networks  Transporting Ethernet over traditional carrier-class network technologies  Nortel Networks  E-Line and E-Lan services over fibre, RPR and DWDM.  Redux Communications   Single-chip solution for transparent tunnelling of E1 traffic over an E-Line service  Riverstone Networks  SLA-based services over Ethernet, ATM and channelised TDM.

Steve Broadhead and Broadband-Testing Labs   

Steve Broadhead runs the newly formed Broadband-Testing Labs, a spin-off from independent test organisation the NSS Group.  

His IT and networking experience dates back to the early 1980s, where he worked deploying and managing PC networks for two insurance companies, after which he made a sideways move into the world of computer journalism. 

In 1991 he formed Comnet, which became the NSS Group, with Bob Walder, specialising in network product testing for suppliers and the publishing industry.  

In 1998, Broadhead created the NSS labs and seminar centre in the Languedoc region of France, offering a wide range of test and media services to the IT industry. Now named Broadband-Testing, it has been created to focus on network infrastructure product testing and related areas.  

Author of recent DSL and Metro Ethernet reports, Broadhead is currently involved in a number of projects in the broadband, mobile, network management and Wireless Lan areas, from product testing to service design and implementation.

Read more on IT strategy