BY FIERCE TELECOM

The evolution of Carrier Ethernet is also fueling the evolution of the Ethernet network interface device (NID), driving the NID to play an everlarger role in ensuring quality of service (QoS).

As more enterprise customers opt for Carrier Ethernet service in the MAN and WAN, service providers want Ethernet NIDs to do a lot more than just serve as the hand-off point between customer and provider.

In fact, enterprise customers want those NIDs to get smart enough to tackle many of the chores involved with measuring and monitoring QoS.

FROM MERE DEMARC TO A SMART, FAST BOX

In terms of monitoring and measuring Ethernet QoS, “the very simplest thing a NID can do is allow you to run a loopback circuit and verify that the circuit is good up to the customer premises,” says Paul Marshall, chief technology officer of Sunrise Telecom, “and that’s a very valuable function.”

Many service providers also appreciate the “end of the line” role played by Ethernet NIDs because their responsibility ends at this point, he adds. “So they say, ‘when we get our 24–hour–a-day monitoring system, why not be sure that that NID is tied into it, so that we’re churning out numbers that give us real-time, end-to-end performance of our circuit, while it’s in service [to the customer?’”

Although Ethernet NID vendors have begun to pack service-differentiation capabilities into their products, Mark Durrett, director of marketing for Overture Networks, says an even more important aspect of the Ethernet NID’s evolution is in the area of Ethernet service protection.

Durrett, who also is co-chair of the Metro Ethernet Forum (MEF) Access Technologies Marketing Working Group, says he expects Ethernet eventually to replace SONET/SDH in the last mile, but resiliency and redundancy, which are built into the SONET/SDH world, “are not really inherent in Ethernet.” Thus, Ethernet NIDs will have to help provide the resiliency in those ring architectures--and be able to run at speeds of up to 10 Gbps as well.

Cloud computing and other high-bandwidth applications are driving both service-provider and enterprise-customer demand for 10 Gbps, he says, noting that even in mobile backhaul, some providers are looking at using 10-Gbps to connect their towers. “So there’s an opportunity for a NID-type device to move into that space as well.”

BACK-TO-BACK ETHERNET NIDS: NECESSARY OR A NECESSARY EVIL?

Because of the über-importance of SLAs and the need to measure and monitor Ethernet QoS against those contracts, retail service providers, wholesale service providers and enterprise customers often deploy back-to-back NIDs, so each can keep an eye on a given circuit’s QoS data.

Brian Rose, senior manager of product development for Cox Business, says this “bookended” NID deployment is necessary in specific situations, at least right now. However, he says he would like to see back-to-back NID deployments disappear, along with some of the NIDs themselves. In their place, he would like transport platforms that integrate smart-NID capabilities; that would allow Cox Business to reduce its capital-expenditure costs and simplify its operations.

“In my humble opinion, most of the NID providers tend to be several years ahead of the accessplatform vendors in capabilities and features. We are pushing aggressively on the transport vendors to implement ITU Y.1731 [performance monitoring], loopback capabilities and NID-like functionality into the transport boxes themselves,” he says.

Rose concedes, however, that Cox will continue to rely on end-to-end NIDs at least in the short term. Even when the company does get a transport-platform vendor to implement these QoS-assurance features, he expects those capabilities will not be everywhere in the Cox network.

“There’s this kind of necessary evil, even in the future, about filling holes,” Rose says. “If I’ve got a customer who’s got 20 locations, we may be using four different access platforms or technologies to get to them, and I need a common denominator. I think that’s where NIDs will continue to serve a purpose, but it’s naive to think that we’re going to use bookended NIDs in the long term.”

THE HYBRID NID

Marshall of Sunrise Telecom says that back-to-back NIDs can be, in and of themselves, a threat to Ethernet QoS. “You’ve extra hardware there, you’ve got things that can fail, you’ve got different combinations- -all the different service providers in the world all have their own brands of NID they like to work with,” he says.

However, the emerging hybrid NID, or “two NIDs in one,” may be a good solution, with one service provider getting to control one-half of the device, and the customer or other service provider getting to control the other half.

“They have a logical delineation of who gets to do what, so it all plays together. Looking at it from afar,” Marshall says, “it just seems to be the most sensible thing--you get one piece of hardware instead of two, and you get the managed interactions that are otherwise totally unmanaged.”

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Throughout the article Paul Marshall, CTO of Sunrise Telecom, is positioned as a thought leader on the topic of how the evolution of Carrier Ethernet is fueling the evolution of the evolution of the Ethernet NID and how it has begun to play a larger role in ensuring QOS is met.