"The open-source movement, which has long made inroads into
corporations via Linux and other enterprise-level software, now has
a potentially bigger target in its cross hairs: the PBXs and
network routers from companies such as Cisco Systems Inc. that form
the basis of networking infrastructure.
"For now, the movement is largely limited to small and midsize
organizations and is focused around the Asterisk open-source
private branch exchange and Vyatta open-source routers. Cisco and
other old-time networking vendors certainly aren't yet shaking in
their boots over it. But it's a growing movement that they ignore
at their own peril; lower-cost, higher-function technologies have a
way of replacing existing architecture far faster than vendors
realize, open-source vendors say..."