>I would like to hear some opinions on MPLS. I have been reading about it, >and, pardon me if I'm wrong, but it seems to me like just a reinvention of >ATM PNNI. Not really. A more accurate analogy would be to say that MPLS is ATM without cells. MPLS has two parts, a forwarding plane and a control plane. PNNI is purely a control plane function. It's based on OSPF, plus a reservation mechanism. MPLS control, however, doesn't have the topology discovery that PNNI does, just the path setup using CR-LDP, LDP, or RSVP-TE. The existence of potential paths to set up typically comes from IP routing. I like to think of MPLS as an overdrive for IP routing, but definitely not, as some people misconstrue it, a replacement for IP routing. There is active work on Generalized MPLS (GMPLS) that extends the forwarding based on frame/packet headers to forwarding based on TDM time slots, wavelengths/lambdas, or physical ports. Obviously, these are more applications for cross-connects of facilities, without the flexibility of per-frame or per-packet decisionmaking. > >I would be very interested in hearing some comments on the future of MPLS. >Particularly since ATM PNNI seemed to have gotten nowhere with the telcos >(and I still don't completely understand why not), then why is MPLS going to >do any better (or is it)? Remember PNNI is "private network to network interface". There are other ATM routing schemes meant for carrier use, such as B-ICI. > >I would be particularly interested in hearing Howard Berkowitz's opinion on >the future of MPLS. Especially considering GMPLS and emerging optical technologies, it is a major direction. It complements, but does not replace, IP routing. Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=5670&t=5670 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
