Technologists push Ethernet to new areas

Ethernet may be a commoditized technology in enterprise LANs but technologists are working to push, pull and stretch the technology into new areas and applications.

A panel discussion at the Next Generations Networks show Tuesday gave a preview of some of these new Ethernet frontiers, which include Layer 2 Ethernet for last-mile access and squeezing 10 billion bits of data over a Category 6 cable (a.k.a., 10G Ethernet over copper).

But before Layer 2 Ethernet can become a reliable, fast WAN access offering for service providers, better management hooks must be built into the technology, said Matt Squire, CTO of Hatteras Networks Inc., a maker of gear that runs Ethernet over copper last mile infrastructure.

“The problem carriers have had with Ethernet is that, unlike IP … there is no intrinsic management layer built into” the technology, said Squire, who is also a member of the Metro Ethernet Forum (MEF), as well as the IEEE’s 802.3ah Ethernet in the First Mile standard taskforce.

The 802.3ah standard, ratified this spring, outlines how Ethernet would run over dual-pair telco copper infrastructure in the last mile, as well as introducing technologies for managing Ethernet more as a service, Squire said.

But more work is needed to make Ethernet a bulletproof service technology. Squire said the MEF and IEEE are working on ways to introduce technologies such as ping and traceroute — ubiquitous tools for troubleshooting Layer 3 IP networks — into the Layer 2 Ethernet world. Technologies that can also warn network equipment of traffic congestion and provide re-route capabilities are also being investigated at the Layer 2-level for first-mile Ethernet.

But the introduction of management and control hooks in Ethernet should not go so far as to complicate the technology, known for its elegant simplicity.

“For things like traffic congestion control, those are best served by end-to-end applications,” Squire said. “We’re looking at ways to optimize traffic control … and make it work better — not to replace existing traffic congestion” management tools.

Another boundary-pushing Ethernet technology is 10 Gigabit Ethernet into over Category 6 copper cabling. While a standard for 10G Ethernet over copper was ratified by the IEEE earlier this year — the CX-4 standard, using Infiniband-style cabling — this does not meet most 10G LAN needs, and is hindering the growth of 10G overall, said George Zimmerman, CTO and founder of Solarflare Communication Inc., a maker of chips that process 10G Ethernet for copper cabling.

“UTP (unshielded twisted pair cabling) has always dominated,” as the choice cabling plant in enterprises, Zimmerman said. This is why “Gigabit Ethernet did not take off until there was a UTP solution was in place.” Now, he said, Gigabit Ethernet is ubiquitous — a standard on many laptops and PCs, and available at under $50 per port.

The finished standard for 10G over Category 6 is won’t come until mid-2006, Zimmerman said. This is due partly to the technical challenges involved in migrating 10G to UTP cabling. At one time, Zimmerman said Fast and Gigabit Ethernet over copper were thought to be impossible, due to cross talk and jitter issues involved with running that much data over a copper line. With 10G Ethernet, those problems, are exponentially bigger, Zimmerman said.

Running 10G over UTP creates so much noise — extraneous signals that interfere with actual data transmission — on a copper line that technologists have had a hard time coming up with ways to make it work reliably. This 10G-produced noise can interfere with signals traveling on a single copper wire, Zimmerman said, as well as signals transmitting over adjacent wires in a cable bunch. This is why the 10GBase-T standard is aiming at a specially-qualified, enhanced Category 6 cable, which can cut down on internal wire and external or “alien cross-talk” noise Zimmerman adds.