Byline: Ed Gubbins

When is a router not a router? It's less a riddle than a serious question facing carriers and vendors alike these days. Drastic changes in network architecture fueled by the addition of video and bent by the evolution of Layer 2 and Layer 3 technologies are changing the function routers serve in carrier networks, tempting one to answer the above question with: Sooner than you might think.

An increasingly sophisticated generation of carrier Ethernet gear is taking more and more work off the hands of today's routers, leading to an evolving role for routers and IP/MPLS technologies in the network. As carriers rebuild their networks for a new generation of services, they must find their own balance of Layer 2 and Layer 3 technologies, even as products based on those technologies play an ongoing tug-of-war over network functions.

"Edge routers are now replicating core router functionality further out in the network, and Ethernet switches are being substituted for routers in many cases because their port costs are much cheaper," Sam Greenholtz, co-founder of consultancy Telecom Pragmatics, wrote in a June report.

And its not just happening in edge networks. Only weeks after its official christening, Nortel Networks' Metro Ethernet division used the Globalcomm 2006 trade show earlier this month to argue for the replacement of IP/MPLS routers in metro networks with its own 8600 Metro Ethernet Switch. …

Log in to your account to read this article – and millions more.