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MPLS –TP Fault OAM draft-ietf-mpls-tp-fault-03. George Swallow swallow@cisco.com IETF79 November 2010. Changes. Restricted Range on Timer values New section on minimum implementation requirements Basically what is expected of a pure transport box Clarified text on setting LDI flag
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MPLS –TP Fault OAMdraft-ietf-mpls-tp-fault-03 George Swallow swallow@cisco.com IETF79 November 2010
Changes Restricted Range on Timer values New section on minimum implementation requirements Basically what is expected of a pure transport box Clarified text on setting LDI flag General editing
Issue arises when a fault times out but BFD does not come back up When do you cease suppressing alarms? Consider an LSP from A to D Timer Values A B C D
Scenario Link B-C fails BFD goes down B sends AIS/LDI to A (not necessarily in that order) A raises a yellow alarm Link C-D fails C “sends” AIS/LDI to A with a long timeout Link B-C comes up B clears AIS (or AIS times out) BFD does not come up When does A raise a red alarm? X X A B C D
Solution To bound the time that A needs to wait limit maximum time between successive AIS messages Proposed max value is 20 seconds If you allow for three periods this bounds it at 1 minutes For comparison Y.1731 allow a max value of 1 minute
Minimum Implementation Requirements Sending AIS and LKR messages at a rate of 1 per second. In particular other values of the Refresh Timer and setting the R flag to value other than zero need not be supported. Support of setting the LDI flag. Receiving AIS and LKR messages with any allowed Refresh Timer value
Support of receiving the LDI flag. Support of receiving the R flag. All TLVs. Items optional to implement
Next Steps Request last call