At 2:52 AM +0000 9/30/02, nrf wrote: >""Chuck's Long Road"" wrote in message >[EMAIL PROTECTED]">news:[EMAIL PROTECTED]... >> hey, friends, I'm always interested in learning something I didn't know >> before. not claiming to know a whole lot about MPLS, but in terms of >> operation, MPLS operates on top of a routing protocol, any routing >protocol, >> correct? Requires that CEF is enabled, at least in the Cisco world, but >any >> old routing protocol is fair game as the transport piece, correct? >> >> So to me, the question would become one of the relative merits of any >> routing protocol, without the MPLS issue clouding it. I would think, but > > what do I know?
As long as the routing protocol gives MPLS path setup the topology information it needs (see below), the protocol is irrelevant. Realistically, most such development is being done in ISIS and OSPF. So a direct comparison between routing protocols and MPLS doesn't make sense, although when I was at Nortel, there was a widespread (and wrong) assumption that somehow, magically, MPLS would replace IP. Why are you considering MPLS? I still consider it more of a carrier mechanism than one for enterprises. What problem are you trying to solve? > > >I got an even more fundamental question - why does MPLS require IP at all? >At the risk of starting a religious way, it's not called Internet Protocol >Label Switching, it's Multi-protocol label switching. MPLS has effectively >become a feature of IP, as opposed to a generalized control-plane mechanism >for which is what it was originally intended. > Let me offer a different way to look at it. MPLS really isn't monolithic. As a sub-IP protocol in the IETF, basic MPLS still has separable forwarding and control plane aspects. The control plane involves path setup protocols such as RSVP-TE and LDP. These, in turn, have to get overall topology information from _somewhere_. Besides IP routing protocols and PNNI, what is there for that purpose that wouldn't need to be invented? Generalized MPLS (GMPLS) is certainly not IP only, as packet forwarding is only one of its modes. It can set up forwarding based on wavelengths, time slots, or ports. The first MPLS predecessor, Ipsilon's (now part of Nokia) IP switching was planned as a faster means of lookup than conventional routing. With advances in L3 hardware and software, that simply didn't turn out to be useful or even scalable. Those initial implementations, by Ipsilon, were ATM dependent both for path setup and transport. > >> >> I suppose there are always the issue of interoperability. >> >> I would certainly appreciate the wisdom of the folks on this group. >> >> Chuck >> >> >> >> ""Kohli, Jaspreet"" wrote in message >> [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... >> > I am looking for a comparative design question: Why a large corporation >> > should or should not use MPLS over EIGRP . Any useful links will be > > > greatly appreciated . Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=54545&t=54507 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
