The following errata report has been submitted for RFC5880, "Bidirectional Forwarding Detection (BFD)".
-------------------------------------- You may review the report below and at: http://www.rfc-editor.org/errata/eid5205 -------------------------------------- Type: Technical Reported by: Dave Katz <[email protected]> Section: 6.8.4 Original Text ------------- If Demand mode is not active, and a period of time equal to the Detection Time passes without receiving a BFD Control packet from the remote system, and bfd.SessionState is Init or Up, the session has gone down -- the local system MUST set bfd.SessionState to Down and bfd.LocalDiag to 1 (Control Detection Time Expired). Corrected Text -------------- If Demand mode is not active, and a period of time equal to the Detection Time passes without receiving a BFD Control packet from the remote system, the session has gone down -- the local system MUST set bfd.SessionState to Down and bfd.LocalDiag to 1 (Control Detection Time Expired). Notes ----- This is based on an email I received from Anil Kumar of Nokia ([email protected]). The language as originally written made a session timeout a no-op when in Down state. This was a gratuitous attempt to avoid a null state transition, but had the side effect of not setting the diag code (and otherwise is no different). This turns out to be problematic in the case where system "A" signals AdminDown, causing system "B" to respond with Down state. If the link then fails, the existing verbiage implies that "B" will not report the detection timeout, even locally. If the link fails in a unidirectional manner (such that "B" is deaf), B will give no indication of a timeout in its outgoing Control packets back to A (which can in fact hear them). Making the suggested change should ensure that the diagnostic code is always set to Detection Time Expired when Control packets stop arriving, even if the far end system was previously reporting AdminDown. Instructions: ------------- This erratum is currently posted as "Reported". If necessary, please use "Reply All" to discuss whether it should be verified or rejected. When a decision is reached, the verifying party can log in to change the status and edit the report, if necessary. -------------------------------------- RFC5880 (draft-ietf-bfd-base-11) -------------------------------------- Title : Bidirectional Forwarding Detection (BFD) Publication Date : June 2010 Author(s) : D. Katz, D. Ward Category : PROPOSED STANDARD Source : Bidirectional Forwarding Detection Area : Routing Stream : IETF Verifying Party : IESG
