[Ospf-manet] LSA reduction
Richard Ogier <rich.ogier@earthlink.net> Tue, 20 February 2007 19:53 UTC
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Date: Tue, 20 Feb 2007 11:53:38 -0800
From: Richard Ogier <rich.ogier@earthlink.net>
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Subject: [Ospf-manet] LSA reduction
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All, Since there has been recent focus on LSA reduction, I want to give some background and explain what the MDR draft specifies regarding LSA reduction. First, as stated in Section 9.2, the MDR draft allows any choice of LSAs subject to the following two requirements: (1) A router MUST include all Full neighbors in its router-LSA. (2) A router MUST NOT include any non-routable neighbors in its LSA. Any LSA choice satisfying the above requirements is therefore compliant with the MDR draft (including the LSA methods implemented in GTNetS whether or not they provide shortest paths). This allows much flexibility in the choice of neighbors to advertise in LSAs. When several design team members were planning to proceed with a standards-track draft based on MDRs (last year), there was agreement that we should keep LSAs flexible, and that specific LSA choices/algorithms would be the subject of future work. Although the MDR draft described some choices for LSAs (minimal LSAs, min-cost LSAs, MDR full LSAs, and full LSAs), these were only suggested choices, not requirements. These specific methods (except for the extreme cases of minimal LSAs and full LSAs) were not going to be included in the planned standards-track draft, and are not going to be included in the experimental draft. The recent focus on LSA reduction, and on providing minimum-cost routing, is therefore a topic that was considered future work by many of us (and certainly not the main focus of the OSPF-MANET work). I think now is a good time to do this "future" work. INRIA has already made some progress in this area, and a method for LSA reduction will soon be decided for OSPF-MDR. One of the questions that needs to be answered is the following: Q: Should the OSPF extension be *required* to always provide minimum-cost routing, or should suboptimal routing be allowed as an option in order to reduce overhead? In any case, the MDR draft will describe a method for LSA reduction that provides minimum-cost routing. I am currently experimenting with a few candidate methods and one of them will be included in the next revision of the MDR draft. Richard _______________________________________________ Ospf-manet mailing list Ospf-manet@ietf.org https://www1.ietf.org/mailman/listinfo/ospf-manet
- [Ospf-manet] LSA reduction Richard Ogier