Verizon Communications Inc. (NYSE: VZ) announced Tuesday that it's going to use the Cisco Systems Inc. (Nasdaq: CSCO) CRS-3 core router, with deployments starting during the first half of 2012.

The routers will be used in certain U.S. markets including Atlanta, Boston, Chicago, Dallas, Los Angeles, New York and Seattle,Verizon's release says. The motivation is to add 100Gbit/s to the core of the FiOS network and possibly to edge networks as well.

Why this matters
Verizon already uses the CRS-1; in fact, at one point in 2009, Verizon was the largest CRS-1 customer. So, in that sense, this isn't a surprise. (See Cisco Lands Verizon.)

But Verizon also uses core routers from Juniper Networks Inc. (NYSE: JNPR). In fact, Juniper has been the router star in Verizon's 100Gbit/s trials and deployments so far, including a buildout in the United States. So, this announcement means Cisco at least gets to put its name on a Verizon 100Gbit/s announcement, too.

But is Cisco nudging into Juniper's piece of Verizon? It's not so far-fetched; a year ago, Juniper may have won a deal in the opposite direction. Juniper's core-router sales for the fourth quarter of 2010 were up 48 percent compared with the previous quarter, possibly driven by "a competitive win at Verizon (vis-à-vis Cisco) for a piece of the RBOC’s private IP backbone," analyst George Notter of Jefferies & Co. Inc. wrote at the time.

In any event, both vendors seem to have secured their spots in Verizon's 100Gbit/s plans.

For more
Here are links to Verizon's recent 100Gbit/s work with Juniper, and to Cisco's CRS-3 news with a certain other carrier.

— Craig Matsumoto, West Coast Editor, Light Reading