GPL vs BSD Licence

[TM4525 at aol.com]

In a message dated 10/26/04 2:32:58 AM Eastern Daylight Time, 
tedm at toybox.placo.com writes:
Actually a more interesting example is some of the Linksys routers
do indeed use an embedded Linux along with Zebra as the routing engine.

Ted
 Or Allot communications, who openly advertise the use of linux, but do 
not make source available to an obviously modified kernel.. I believe they 
claim that the GPL is optional.