The draft states that
" The proposed mechanism is limited to the link down event in order to keep the mechanism simple."
Since a link that goes down will normally also come up again, the draft ought to provide some guidance to the operator on how they should handle that situation. Applications that care about the disruption caused by microloops presumably have no care as to whether they are cause by link up or link down, and so would prefer a complete elimination of that disruption. However I accept that complete elimination has wider network impact and that this approach which is really microloop mitigation has utility.
The advice might be as simple as keeping the link out of service until a quiet time, or the loss of connectivity has moved to the network to a state of fragility such that disruption is acceptable.
- Stewart On 20/09/2017 19:44, The IESG wrote:
The IESG has received a request from the Routing Area Working Group WG (rtgwg) to consider the following document: - 'Micro-loop prevention by introducing a local convergence delay' <draft-ietf-rtgwg-uloop-delay-06.txt> as Proposed Standard The IESG plans to make a decision in the next few weeks, and solicits final comments on this action. Please send substantive comments to the [email protected] mailing lists by 2017-10-04. Exceptionally, comments may be sent to [email protected] instead. In either case, please retain the beginning of the Subject line to allow automated sorting. Abstract This document describes a mechanism for link-state routing protocols to prevent local transient forwarding loops in case of link failure. This mechanism proposes a two-step convergence by introducing a delay between the convergence of the node adjacent to the topology change and the network wide convergence. As this mechanism delays the IGP convergence it may only be used for planned maintenance or when fast reroute protects the traffic between the link failure time and the IGP convergence. The proposed mechanism is limited to the link down event in order to keep the mechanism simple. Simulations using real network topologies have been performed and show that local loops are a significant portion (>50%) of the total forwarding loops. The file can be obtained via https://datatracker.ietf.org/doc/draft-ietf-rtgwg-uloop-delay/ IESG discussion can be tracked via https://datatracker.ietf.org/doc/draft-ietf-rtgwg-uloop-delay/ballot/ The following IPR Declarations may be related to this I-D: https://datatracker.ietf.org/ipr/2565/
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