The State of IP

If anything, the move to IP – and IP-centric technologies like MPLS and Ethernet – is happening even more quickly in the enterprise, where businesses "are trading out T1, ATM and frame relay as fast as they can," said one source. In the enterprise, the move to IP is both a basic network connectivity change as well as an enabler of an added level of intelligence in the network cloud (more on that later) that ultimately gives businesses a better, more managed level of communications services and applications.

One of the next big steps is pure IP-to-IP interconnection between networks. In the enterprise, this idea of keeping IP as IP is leading to a boom in business SIP trunking services, where former islands of IP PBX connectivity are now connecting to PSTN IP backbones via IP and SIP, improving the economics of enterprise voice and laying the groundwork for more advanced, end-to-end IP voice features and services.

What is more traditionally thought of as interconnection – peering between carriers – is also moving to an all-IP environment, albeit a bit more slowly. Next generation wireless operators may end up leading the way in IP peering, but traditional wireline carriers and especially cable operators also see value in passing VoIP traffic onto peers as pure IP. "What is lagging, quite frankly, among all this talk of peering and interconnect at the IP level is that tier ones aren't doing it in any big way right now," said Acme Packet's Hourihan. One initiative in this area is the GSMA IPX, which is aiming to create a standard, global way to exchange IP traffic among mobile and fixed operators – though it remains largely in the trial phase.

For IP interconnect, it may be the case of too much of a good thing, said Jim McEachern, manager-service enabler standards for Nortel. "There are core standards for [IP interconnect] in place, but there are too many of them," he said, adding that there are activities underway, at standards group ATIS and elsewhere, to profile IP interconnect points and better define how IP traffic can be exchanged. One challenge to IP interconnect is that while TDM settlement fees are well-established, many carriers today peer IP traffic with no settlement fees at all -- one back simply scratches the other. That must change before IP interconnect becomes the norm.

Finally, wireless. Today, mobile services such as voice and SMS are delivered almost exclusively via circuit switched networks – in the radio access, mobile switching center and between networks and backhaul points. With 4G technologies like LTE, all that begins to change. Not only do mobile switching centers get IP-enabled, but traffic exchanged between MSC locations, not to mention between networks, begins to move to IP as well. IP even starts to penetrate radio access networks and clients. The move to IP in the mobile network demands an opus all its own, and luckily in this issue we have one (see Mobile Core Wars).

Just as big is mobile backhaul, where specialty backhaul providers and wireline carriers providing backhaul services are beginning to move to IP and Ethernet to deliver not only greater levels of bandwidth but more flexible bandwidth as well. Backhaul provider FiberTower, for instance, is working with vendor Adtran to move its backhaul services from TDM to Ethernet, said Vijay Lewis, FiberTower's director of engineering. "Ethernet today has very low penetration at cell sites; the reason is very cheap T1s bought on five to seven year terms," he said, adding however that growth in data services means that "T1s are a quick fix but not the long-term solution. 2010 is shaping up to be the year of Ethernet backhaul. I said that in 2007 but I was wrong. But now is the time. Mobile service operators have to add smart capacity. [For backhaul provides], that means it's not about adding T1s, but about having Ethernet and being able change capacity on a dime."

The major challenge for backhaul is the timing requirements to put voice traffic on Ethernet. For that reason, many backhaul operators are keeping T1s in place to handle voice and moving Ethernet in to support booming data traffic. Another option is to integrate both by running Ethernet over SONET where possible, with the synchronous nature of SONET transport mitigating those voice timing issues.

For vendor Adtran, IP and Ethernet in mobile backhaul is all about helping carriers move to an integrated access infrastructure serving residential, business and backhaul businesses as efficiently and via as few boxes as possible. "You don't want to build out an expensive fiber to the node network into a neighborhood and not take care of the business across the street," said Mike Martin, Adtran's director or product management for carrier solutions. "If you have cell tower right there, you don't want to run a separate fiber to it but use the GPON network you already have and mix my residential and business and mobile traffic — you've got to make all these services work and play together."

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