1. 1 MPLS –TP Fault OAM draft-ietf-mpls-tp-fault-02 George Swallow swallow@cisco.com IETF78 July 2010

2. 2 Major Changes  Message format Dropped use of ACH-TLVs Extended flag fields  Replaced LDI message with an “LDI Flag” on the AIS message  Added IANA Section  Added Security Section  General editing

3. 3  Dropped use of ACH-TLVs After talking with many hardware engineers, decided that these were not particularly silicon friendly Important stuff for hardware is in fixed locations Moved information into TLVs internal to the message These can be stored for examination by software or punted up to software  Extended flag fields Added another flag, which left only two, so changed format to allow for eight Could allow for message format alignment with other drafts Message format

4. 4 Link Down Indication  Replaced LDI message with an “LDI Flag” on the AIS message  LDI is only need when CC is running slowly If CC is running fast (detect time ~500 ms or less) then LDI is treated just like AIS  Semantics and the procedures remain the same

5. 5 Link Down Indication (LDI)  Setting the LDI flag is driven from the APS state  LDI flag must be set whenever the server layer enters the unavailable state  When LDI is received by an MPLS-TP LSP’s MEP it is used to Suppresses alarms due to any CC failure – just like AIS May be used to trigger path protection e.g. CC is running slowly and no CC failure has occurred

6. 6 AIS / LDI Fault Generation Client LSP Server Working LSP Server Protection LSP

7. 7 Example 1: An unprotected link Server Path is unprotected Control function tells Server MEP W to set LDI flag when generating AIS messages Server Path W Server MEP W Client Path Server APS/Control

8. 8 Example 2: Both Working and Protection are Up CC functions are reporting that both W and P are up APS is in the Normal State Control Function tells both MEPs to clear the LDI flag when generating AIS messages Server LSP P Server LSP W Server MEP P Server MEP W Client Path Server APS/Control

9. 9 Example 3: Protection Up, Working Fails Server LSP W fails, Server MEP W begins sending AIS with LDI = 0 APS / Control Function moves selector to Protection LSP AIS ceases to be inserted in Client LSP APS enters Protecting State, Control Function tells Server MEP P to set LDI flag (= 1) when generating AIS messages Server LSP P Server LSP W Server MEP P Server MEP W Client LSP X Server APS/Control

10. 10 ACH Codepoint  An ACH Codepoint was requested through the early allocation procedures  The codepoint has been assigned 0x0058 Fault OAM (TEMPORARY - expires 2011-07-16)

11. 11 Next Steps  Add a more complete section about setting LDI Flag  Address any comments  Republish  Request last call