[Pce] Virtual Network Topology (VNT) changes and IP layer routing loops
Greg Bernstein <gregb@grotto-networking.com> Mon, 05 June 2006 16:17 UTC
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Date: Mon, 05 Jun 2006 09:17:24 -0700
From: Greg Bernstein <gregb@grotto-networking.com>
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Subject: [Pce] Virtual Network Topology (VNT) changes and IP layer routing loops
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Hi folks, in drafts draft-ietf-ccamp-gmpls-mln-reqs-00.txt and draft-ietf-pce-inter-layer-frwk-00.txt the concepts of multi-layer and multi-region networking are defined and discussed. An important case is when the IP layer rests directly upon a "virtual network topology" layer that we will desire to change via GMPLS signaling. Changes to the IP layer VNT can produce "transient IP layer routing loops" also known as "micro loops" which can last 100's of mili seconds or more. Hence any time we change a connection between IP layer routers via GMPLS we can cause significant outages compared to the recovery times that we set out to achieve with GMPLS fast reroute and other mechanisms such as SDH APS (rings and linear). At the Routing working group, Alex's draft draft-ietf-rtgwg-microloop-analysis-01.txt provides some analysis and a method to reduce the impact (duration too) of the transient loops. More recently the drafts: (1) draft-bryant-shand-lf-applicability-01.txt (2) draft-bryant-shand-lf-conv-frmwk-02.txt (3) draft-francois-ordered-fib-01.txt Address this problem more generally including in (3) a method that guarantee loop free convergence. The problem is that these have generated very little interest at the RTG WG and may not move forward. This area is not within PCE or CCAMPs charter but can have an impact on the adoption of GMPLS in multi-layer/region networking. If you're interested please take a look and comment to the RTG WG. Note I wasn't involved with writing these, but came across them when considering the effects of GMPLS changes on the IP layer VNT. Thanks Greg B. -- =================================================== Dr Greg Bernstein, Grotto Networking (510) 573-2237 _______________________________________________ Pce mailing list Pce@lists.ietf.org https://www1.ietf.org/mailman/listinfo/pce
- [Pce] Virtual Network Topology (VNT) changes and … Greg Bernstein
- RE: [Pce] Virtual Network Topology (VNT) changes … Don Fedyk
- Re: [Pce] Virtual Network Topology (VNT) changes … Greg Bernstein
- Re: [Pce] Virtual Network Topology (VNT) changes … Kohei Shiomoto
- Re: [Pce] Virtual Network Topology (VNT) changes … Greg Bernstein
- Re: [Pce] Virtual Network Topology (VNT) changes … Kohei Shiomoto
- Re: [Pce] Virtual Network Topology (VNT) changes … JP Vasseur
- RE: [Pce] Virtual Network Topology (VNT) changes … Don Fedyk
- Re: [Pce] Virtual Network Topology (VNT) changes … Olivier Bonaventure