Cisco’s IPoDWDM may be tough sell to some

In April, as Cisco touted IP/optical integration at the OFC/NFOEC trade show, Glen Wellbrock, director of network technology development for Verizon Business, told Telephony in an interview that IPoDWDM was “a marginal cost savings… but it is beneficial in that it’s fewer things to manage and spare.” He also argued that the use of alien wavelengths limits network performance because the transport gear has less visibility into the signal.

Cisco argues that the three main justifications for an intermediate step between IP and optical gear have been rendered obsolete. Routers are already performing the 10 Gb/s and 40 Gb/s aggregation that optical crossconnects do. Multiprotocol label switching fast reroute provides the 50 millisecond protection that a Sonet device would. And adding a G.709 “digital wrapper” to wavelengths in the router offers visibility on signal performance to network management systems.

Wellbrock also said something then that Nicklas repeated: The leading router vendors, such as Cisco, aren’t also the leading optical equipment vendors. So carriers might be more comfortable trusting their long-haul optics to companies with more expertise in that area. In addition, leading optical vendors such as Nortel Networks and Ciena are pushing the envelope of long-haul technology, using increasingly sophisticated modulation to reach longer spans and higher speeds, Nicklas said, predicting Cisco is not likely to take the lead in those advancements any time soon.

Cisco claims its sales of 40-Gb/s IPoDWDM interfaces have grown “well over 1000%” over the past year, though the vendor won’t say how many interfaces that amounts to or what percentage of CRS-1 sales. Among the publicly announced customers are German incumbent carrier T-Com and Swedish carrier TeliaSonera.

Meanwhile, Meriton Networks has positioned its optical transport platform in contrast to Cisco’s approach, pushing the importance of keeping transport and service layers separate.

Carriers with pure IP networks may be more receptive to the IP/optical integration pitch than those with large legacy networks, one reason Comcast makes sense as an early adopter of the approach. As carriers migrate more to IP over time, they may become more interested as well. But that will be a slow process.

“The aspect of IPoWDM where the optical transmission/bandwidth management layer disappears is not likely to happen soon,” said Mark Seery, vice president of switching and routing at Ovum. “Optical networking remains a hard problem, optical components remain low yield (relative to silicon components) variable characteristic components that result in the need to do skilled optical engineering. There are a set of technology and organizational issues that have not fallen in to place yet, but I expect a win [for IPoDWDM gear] here and there.”