Anything which routes on both source and destination addresses is a form of circuit switching in disguise. At least from the point of view of routing information needed. Thus MPLS is no different from ATM in regard to computational complexity of algorithms involved. (Note that there's such thing as statically-configured PVCs, of MPLS used for manually-configured TE; those mereley augment physical network topology, from the point of view of dynamic routing level). Tunnels do _not_ inject any routing information into backbone. As long as they aren't created and destroyed "on demand" (with corresponding updates to network's routing info) they're safe. --vadim On Tue, 7 Aug 2001, Christian Kuhtz wrote:
On Tue, Aug 07, 2001 at 06:25:50PM -0700, Vadim Antonov wrote:
The point is very simple - virtual circuit routing does not scale. That was beaten to death in ATM vs IP discussions years ago.
What does this have to do with VC routing?! And tunnels are probably closer to VC routing than 2547(bis) style VPNs. What is your point?
-- Christian Kuhtz <ck@arch.bellsouth.net> -wk, <ck@gnu.org> -hm Sr. Architect, Engineering & Architecture, BellSouth.net, Atlanta, GA, U.S. "I speak for myself only."