Red hot Carrier Ethernet

Having resoundingly conquered the LAN space, Ethernet technology now is rapidly spreading its wings in the MAN and WAN markets and being considered for applications as disparate as the local loop, home networking, telematics and computer backplanes.

At the same time, the speed of Ethernet is being ramped up - toward the end of last year the IEEE agreed to aim at 100 Gbps as a target for its future evolution - and the protocol now finds itself being run over thick and thin coax, telephone pairs, cable TV networks, power line, optical fibers and wireless bearers.

It's not difficult to understand Ethernet's growing popularity. There are relatively low costs associated with its deployment and operation. It is easy to use and enjoys interoperability with installed LANs. It can carry different traffic types. And Ethernet is highly scalable and offers increasingly high-speed performance.

The Metro Ethernet Forum (MEF) notes that the cost structure of Ethernet is shaped both by the considerable economies of scale that result from the near-ubiquitous enterprise LAN use of the technology and also by its relative technical simplicity. In general, the per-port price of new generation Ethernet equipment tends to be driven down to the level that triggered the mass adoption of the previous generation; at the point where that level is reached, the new generation becomes the subject of mass adoption, and the process repeats with the next generation.

Tipping point

This tipping point is currently being approached for Gigabit Ethernet, which some project will take the place of Fast Ethernet to become the Ethernet 'norm.' This is not necessarily all good news for Ethernet equipment vendors: as prices fall, the increase in volumes shipped may not compensate for the reduction in revenues. For example, Infonetics Research in a recent report calculated that in the year 2005 to 2006, worldwide Ethernet 10/100 port shipments grew 11% but switch revenue fell.

Ease of use and interoperability are other attributes for Carrier Ethernet. With Ethernet in both the LAN and MAN/WAN, the need for interworking at the CPE between, say, Ethernet and frame relay is removed. Configuration and ease of provisioning is also simplified.

Ethernet is able to carry voice, data and multimedia traffic, an increasingly important capability as the number of converged applications in the business, residential and mobile sectors multiplies.

Since it was, so to speak, sprung from the confines of the enterprise LAN, one of the most high profile and successful re-inventions of Ethernet has been as telco Carrier Ethernet.

Michael Howard, principal analyst at Infonetics Research, says growth in this area has been strong. 'Carrier Ethernet switch and router (CESR) manufacturer revenue worldwide grew an astounding 132% from 2005 to 2006, and will continue strong growth to $9.1 billion in 2010, a five-year CAGR of 16%,' says Howard. 'Carriers clearly want, and are deploying, Carrier Ethernet qualified routers and Ethernet switches. Meanwhile, other technologies are in decline, as worldwide spending on metro SONET/SDH equipment hit a peak in 2006, and will be lower than CESR in 2007, with a negative five-year CAGR through 2010.'

There may be even greater growth ahead. New MEF COO Kevin Vachon draws attention to the technology's massive untapped market potential beyond fiber infrastructure, and the role of Ethernet access via bonded copper, coax and wireless technologies, where Ethernet is '"&brkbar;the logical choice with no rival protocols on the horizon.'


Mid-band expectations

Ethernet over bonded copper is a relatively new kid on the Carrier Ethernet block, but one to which considerable expectations are attached. Following the ratification in mid-2004 by the IEEE of a new amendment to the 802.3ah Ethernet in the First Mile (EFM) standard, this Ethernet-over-copper technology - widely dubbed mid-band Ethernet - appears in two flavors.

The asymmetric/symmetric 10Pass-TS flavor is based on VDSL, and the 2Base-TL symmetric service is based on the same physical layer as Enhanced SHDSL. 10Pass-TS can offer asymmetric rates of around 100Mbps, and 50 Mbps symmetric. In principle, 2Base-TL provides nominal symmetric data rates of 2.3Mbps over 2,700 to 3,600 meters and 5.7Mbps over shorter distances, with the standard defining a multi-pair bonding scheme that enables eight pairs to deliver 45Mbps over short distance and up to 20Mbps over a typical carrier serving area. In effect the two pairs that deliver 2Mbps for an E1 connection in principle can now deliver 11.4Mbps.
Mid-band Ethernet is being marketed as a solution for small- and medium-sized businesses that have outgrown their E1/T1 facilities but don't need very large capacities at which conventional Metro Ethernet services typically start. As such it's hailed a precursor to, and sometimes substitute for, fiber network rollouts.

This pitch exploits the circumstance that fiber is still a minority sport: as of last year, only around 10% of European enterprises and 13% of their US counterparts, had been glassed up. Aside from delivery of real Ethernet services to SMBs, other applications for mid-band Ethernet include cellular, DSLAM, and fixed and meshed wireless network backhaul.

US carrier BellSouth (now part of AT&T) has become a large-scale pioneer of mid-band Ethernet using solutions supplied by Hatteras Networks. Other service providers considering the new technology include  BT, COLT, Easynet, Finnish data group Finnet, Hungary's T-Com, Norway's Telenor, and CenturyTel,  and US-based TDS Telecom and XO Communications.

Three new recruits in February signed up to the mid-band Ethernet service provider roster. US broadband provider InfoHighway Communications introduced Metro Ethernet services using Actelis' solutions. US business grade IP service provider Telekenex announced it was deploying an end-to-end system jointly supplied by Hatteras and Cisco Systems. And Australia's PowerTel, a provider of infrastructure-based data, voice and Internet services to corporate and wholesale markets, said it would roll out Hatteras mid-band Ethernet services offering  2 to 40Mbps symmetrical Ethernet over copper throughout Australia.

'Business customers connected to the copper network are a huge opportunity for PowerTel, and our mid-band Ethernet service offering provides a compelling upgrade to legacy E1 services,' said PowerTel managing director Paul Broad. 'PowerTel's enterprise customers will no longer have to wait for fiber to get high-performance, high-value Ethernet services. With Hatteras Networks equipment, we can extend the Ethernet service edge of our network to all businesses today.'

All of which looks and sounds pretty much like Ethernet is rapidly acquiring another string to its already multi-stringed carrier bow. Ethernet is already in the MAN, the WAN, the local loop and in the Wi-Fi hotspot sector. Next stop‾ Perhaps the world.

Faster and more scalable


Just how scalable is Ethernet‾ Well last year after an evaluation by Iometrix, (the lab used to certify Carrier Ethernet products and services for the MEF) Extreme Networks announced that its BlackDiamond 12K multidimensional Ethernet switch had demonstrated Carrier Ethernet scalability of up to 16 million users in what was claimed as the industry's first test of MAC-in-MAC encapsulation technology.

'The last hurdle for Ethernet to effectively meet the demands of service provider networks is scalability,' said Bob Mandeville, founder and president of Iometrix. 'Until Ethernet can effectively scale to support hundreds of thousands of users, it will not be a legitimate solution at the core. This test, the first of its kind, has shown that MAC-in-MAC and Extreme Networks' implementation of multidimensional Ethernet delivered that scalability.' 

Ethernet is also getting ferociously faster. Some see the desktop adoption of Gigabit Ethernet as imminent, with 10-Gigabit Ethernet eventually becoming widespread in the backbone or core. There's much discussion about the potential market for 40-Gigabit Ethernet and the IEEE has endorsed work on 100-Gigabit Ethernet.

In practice, 100-Gigabit demos are already underway. Last November, a team of organizations including Finisar, Infinera, Internet2, Level 3 Communications and the University of California at Santa Cruz, mounted a demonstration of 100-Gb Ethernet that showed  the technology was viable and capable of implementation in existing optical networks with 10-Gbps wavelengths. This trial also highlighted how next-generation technology could address the emerging bandwidth needs of network providers and their users as advanced Internet-based applications continue to proliferate.

The system successfully transmitted a 100-Gb Ethernet signal from Tampa, Florida to Houston, Texas, and back again, over ten 10 Gbps channels through the Level 3 network. This was the first time a 100-Gb Ethernet signal has been successfully transmitted through a live production network.

'This successful demonstration shows that this concept of 100-Gb Ethernet over 10 x 10 Gbps DWDM works and provides a near future implementation path,' said Dr. Daryl Inniss, VP of Ovum-RHK's Communication Components research.


Tunnel visionaries

Something of a contest for the hearts, minds and wallets of Carrier Ethernet service providers is developing between the proponents of two tunneling mechanisms that are intended to make Ethernet 'connection-oriented' without sacrificing its scalability, reliability or manageability.
In one corner, backed by the likes of Nortel and Extreme Networks, sits Provider Backbone Transport (PBT). In the other is Transport-MultiProtocol Label Switching (T-MPLS) which has been worked on by companies such as Alcatel-Lucent, Huawei and Tellabs.

According to Nortel, PBT adds the deterministic service delivery with carrier-grade resiliency that until now was missing from Carrier Ethernet networks. Company officials note that by using PBT, operators can create Ethernet paths that reserve necessary bandwidth and support the provisioned quality of service (QoS) metrics that guarantee service level agreements (SLAs) will be met.

However, Extreme Networks has a different view. 'PBT offers three key benefits in Carrier Ethernet networks,' says Peter Lunk, director of service provider marketing at the company. 'First, is the de-layering of the network, a simplified approach to building and managing Carrier Ethernet networks.


Second, it cements Ethernet's role in the network and provides a secure foundation for creating truly scalable networks. Finally, it has significant capex and opex advantages that are always attractive to carriers.'

Proponents of T-MPLS say it is further along in the standardization process and it supports mapping of multiple services such as frame relay and ATM.

The final choice is yours.