Nan Chen, CENX: Pioneering Carrier Ethernet

Nan Chen, CENX: Pioneering Carrier Ethernet

In the space of just over 10 years, Carrier Ethernet has evolved into a $20 billion global industry. Alex Hawkes talks to CENX and MEF president Nan Chen – a key figure throughout the Carrier Ethernet revolution and a pioneer of the Carrier Ethernet exchange.


During the 1990s, 10Mbps, 100Mbps and 1,000Mbps Ethernet was flourishing in enterprise and consumer markets. Network hardware vendors such as Bay Networks had been working tirelessly to create new Ethernet products based upon ever faster 10Gbps Ethernet. Although not well understood at the time, it was this new Ethernet technology which was destined to revolutionise the carrier market.

The company was sold to Nortel in the summer of 1998 for $9.1 billion, but one of its employees was to go on and play a pivotal role in what came next. “We had developed a new technology and the next stage was figuring out how the industry can implement it,” says Nan Chen, president of both CENX and the Metro Ethernet Forum (MEF). “We quickly realised that the metro networks which were operated by Tier 1 service providers were where this technology needed to be.”

In hindsight, this proved to be a masterstroke. Spurred onwards by the work of the newly formed MEF, Carrier Ethernet quickly dominated the metro networks and became the linchpin for provider-based networking services, eventually amalgamating in the creation of the industry’s first Carrier Ethernet exchange operated by CENX. Chen gives his personal account of the history and meteoric rise of Carrier Ethernet.

Becoming carrier class

With its highly scalable speed and almost 100% presence at all network end points, Ethernet was attracting interest from carriers by the turn of the 20th century. However, at this point Ethernet was an enterprise technology and there was a distinct need to enhance it to be carrier class. The MEF was therefore founded in May 2001 by Chen with the goal of accelerating the global adoption of Carrier Ethernet networks and services – or, in other words, to make Ethernet a carrier-class technology and service.

The forum’s most immediate challenge was to clarify to the industry what Carrier Ethernet had to offer. “Many companies at the time had various interpretations of what Carrier Ethernet actually is. MEF therefore defined Carrier Ethernet as Ethernet plus five carrier-class attributes,” says Chen. “These are standardised services, scalability, reliability, quality of service (QoS) and service management.”

Using those attributes, the forum then turned its sights towards certifying Carrier Ethernet equipment. With MEF-compliant equipment becoming utilised by the industry, in 2006 the MEF moved on to certifying Carrier Ethernet services.

“The MEF certification of services was revolutionary in two respects,” says Chen. “Firstly, we had the likes of Verizon and AT&T onboard and these are companies that had never previously been certified by a third party. Secondly, MEF compliancy was not just based on functionality but also performance. The performance side is an area which companies had previously not wished to disclose. We opened the industry up to a new level of transparency. That’s the moment when Carrier Ethernet really came on fire.”

The interconnection dilemma

With the likes of AT&T and Verizon turning from offering private-line services to instead deploying MEF-certified Carrier Ethernet services to enterprise clients, the surge in bandwidth continuously helped drive forward the adoption of Carrier Ethernet. However, at the same time a real and very apparent challenge was emerging. By replacing private-line services with Ethernet, the need for service providers to reach outside their traditional domestic footprint became increasingly essential. Large organisations with offices across the world forced primary communications providers to work with providers abroad to leverage their networks.

“This is where we ran into some difficulties,” says Chen. “As a technology, Ethernet is very flexible and has many tuneable parameters such as speed and QoS. This makes it a lot easier to serve the needs of customers, but much harder to make it interoperable with other service providers.” A thinktank was assembled by the MEF – including the likes of AT&T, Orange, Tata, Verizon, Level 3, Cable Vision and Cox Communications – that looked to tackle the issue of interconnections head on. Known as the Ethernet Exchange Committee, its members met every two weeks for nine months before coming to a unanimous decision: “The committee felt a third party was needed to come in and implement a Carrier Ethernet exchange. As a result, CENX was formed in early 2009,” says Chen.

First in the market

As the first Carrier Ethernet exchange in the market and with the support of high profile industry figures, it didn’t take long for CENX to become a dominant force. Chen points to the importance of Ethernet service locations (ESLs) as the critical component that drives forward the exchange’s connectivity. “These are really the end points from which you can reach the exchange. They follow the same simple logic as Metcalfe’s law – the value of an exchange is proportional to the number of end points which it can reach.”

In the space of just a year and a half, CENX had accumulated 15 million ESLs worldwide. The company had also established nine Carrier Ethernet exchanges around the world including seven in the US, one in London and another in Hong Kong. Most recently it has introduced a new exchange in Washington at CoreSite’s data centre, which is due to become operational in Q2 of 2011.

“We have a large number of carriers across the world but they tend to be concentrated in particular places. New York, Los Angeles and Hong Kong are emerging as the top three interconnectivity hubs or Carrier Ethernet exchanges in the world due to the high number of inter-continental carriers wishing to exchange there, as well as the extension of domestic footprints,” says Chen.

The future for the Carrier Ethernet exchange

Chen is confident that CENX will continue to expand its geographical coverage in the coming years. What he sees as an even more pressing concern, however, is evolving the Carrier Ethernet exchange model from purely a virtual interconnection service towards one with more of a complete end-to-end service integration.

“As the world migrates from TDM/PSTN to Carrier Ethernet-based networks, voice tandems and interconnect points for PSTN are being replaced by Carrier Ethernet exchanges. Consequently there is a pressing need for the IT systems of Carrier Ethernet exchanges to become integrated with the IT systems of carriers – much like the tandems in TDM/PSTN networks,” says Chen.

“Carriers worldwide are continuing to connect to Carrier Ethernet exchanges as their new interconnect points over Carrier Ethernet-based networks. As much as we no longer want the old legacy that accompanies telephony or TDM/PSTN-based networks, there are still lessons which we can learn there – the real-time on-demand circuit set ups allow connections to be made anywhere in the world between any end points, no matter how many carriers are involved in the process. And that’s something we want to recreate with Carrier Ethernet and Carrier Ethernet exchanges.”

Chen hopes to fulfil his ambitious vision of creating a Carrier Ethernet exchange which offers a telephony-like experience when connecting to end points in the next five to 10 years. Such seamless real-time interconnections he feels will only be possible, however, if “the industry works together.”

“With this singular vision powered by industry forums like the MEF, we will achieve it,” says Chen.

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