RE: MPLS IGP Question

Hi Marcin,

In short, you don't. LDP is an IGP based label distribution protocol. This means that LDP can use information in the routing table that is populated by RIP, EIGRP, OSPF, IS-IS, or static routing. In practice only OSPF or IS-IS are used in service provider core networks because they are extensible for other applications like MPLS Traffic Engineering (MPLS TE).

BGP can also be used, but it is very cumbersome in practice for an internal label distribution mechanism. In practice BGP is only used for label advertisement between different ASes, typically for Inter-AS MPLS L2/L3 VPN exchange. For more info see http://tools.ietf.org/rfc/rfc3107.txt. Additionally RSVP can be used for label distribution over MPLS TE tunnels without the need for either LDP or BGP label allocation.

In regards to the previous poster's assertion that only OSPF can run different processes, this is incorrect. All routing protocols can be used for PE-CE routing exchange (RIP, EIGRP, OSPF, IS-IS, BGP, static routing, and policy routing). The PE-CE routing protocol is completely separate from the internal SP protocol that is used for label allocation.

HTH,

Brian McGahan, CCIE #8593 (R&S/SP/Security)
bmcgahan_at_INE.com
 
Internetwork Expert, Inc.
http://www.INE.com

-----Original Message-----
From: nobody_at_groupstudy.com [mailto:nobody_at_groupstudy.com] On Behalf Of Marcin Zgola
Sent: Wednesday, September 08, 2010 6:48 PM
To: ccielab_at_groupstudy.com
Subject: MPLS IGP Question

Why do I need to run OSPF to exchange labels between LDP neighbors.

Why can't I use static routes or iBGP?

Thanks

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Received on Thu Sep 09 2010 - 00:39:17 ART