Carrier Ethernet grows up

Hammerhead Systems just announced full support for the MEF models for carrier Ethernet and MPLS, as well as interworking between MPLS and PBT (Hammerhead also announced a partnership with Soapstone).

Network operators BT Group and DT have expressed a level of commitment to carrier Ethernet and PBT, and it's pretty likely that in 2008 at least four other major operators will join them. Carrier Ethernet and PBT have got the vendors named here good engagement with operators worldwide; in fact some of these vendors tell me that they're almost consumed with requests for information and for devices to test.

Not everybody loves PBT, particularly router vendors that favor IP/MPLS. Cisco, Juniper Networks and Alcatel-Lucent are counted in the camp of PBT opponents, though they all surely are considering PBT support as operators become increasingly strident in their demands to hear about it. Ericsson's position is less clear, but I've recently heard there is a movement within that company to provide support for PBT in some form. Foundry Networks is said to be looking at PBT as well, but there are no references to it on the company Web site.

The two main drivers behind PBT are stringent SLA control and cost. The adaptive behavior of IP, with its dynamic reconfiguration and routing, makes it difficult to write enterprises the same kind of SLAs they had for frame-relay services, which inhibits convergence. This is one reason an ex-BT executive has given for BT's interest in PBT.

While advances to MPLS -- particularly T-MPLS -- promise similar nonadaptive behavior, carrier-Ethernet switching products are reported by operators to be about 40% less expensive than routers, so PBT has a significant cost advantage over T-MPLS, if there are no other reasons to deploy routers.

Whether the network is a greenfield -- having neither significant router nor significant Ethernet infrastructure -- is the big issue for PBT. If a network is a greenfield, building a carrier-Ethernet PBT network would be significantly less expensive than building a T-MPLS network using routers. Metropolitan networks seem a pretty sure place to deploy carrier Ethernet and PBT, although IPTV in the form offered by Alcatel-Lucent deploys IP features in these networks. In wider-area applications, where some routers are almost certain to be used, the cost advantages of PBT may be smaller. The enhancements to carrier-Ethernet control-plane and service models may make the difference between carrier Ethernet as a niche player and carrier Ethernet as a full-scale infrastructure alternative to IP/MPLS.