1. © 2006 Cisco Systems, Inc. All rights reserved.Cisco ConfidentialPresentation_ID 1 MPLS –TP Fault OAM draft-sfv-mpls-tp-fault-00 George Swallow swallow@cisco.com IETF76 November, 2009

2. © 2006 Cisco Systems, Inc. All rights reserved.Cisco ConfidentialPresentation_ID 2 Fault Notification Various server layer faults need to be communicated to their clients so that alarms can be suppressed and/or corrective action taken at the client layer Three distinct server layer faults have been identified Alarm Indication Signal (AIS) Link Down Indication (LDI) Lock Report (LKR) These fault OAM messages are sent from server layer MEPs to client layer MEPs to report the occurrence of a fault The fault OAM messages are sent in the direction away from the fault

3. © 2006 Cisco Systems, Inc. All rights reserved.Cisco ConfidentialPresentation_ID 3 Sending Fault OAM Messages MEPs exist at link interfaces (server layer) over which MPLS-TP LSPs (client layer) are cross connected Note that this includes an MPLS-TP tunnel interfaces if it were used as a link A MEP is aware of all of its xconnected MPLS-TP LSPs via configuration or signaling When a fault occurs on a link, the MEP associated with the link interface sends fault messages on each of the xconnected LSPs

4. © 2006 Cisco Systems, Inc. All rights reserved.Cisco ConfidentialPresentation_ID 4 Fault Generation (LDI example) MEP PE1P2P3PE4 TP-LSP Physical Links Sk TP LSP 1 is routed PE1 – P2 – P3 – PE4 Link P2 - P3 fails At P2 IF Down detected by MEP L0; At P3 IF Down detected by MEP L1 MEP L0 sends LDI to MEP So; MEP L1 sends LDI to MEP Sk X IF Down IF Down LDI L1L0 So MPLS-TP LSP 1 LDI

5. © 2006 Cisco Systems, Inc. All rights reserved.Cisco ConfidentialPresentation_ID 5 Alarm Indication Signal (AIS) AIS may be sent whenever there is a transient defect in the server layer, e.g. during a protection switch AIS must not be sent if the server layer enters a down state (instead LDI is sent) When AIS is received by an MPLS-TP LSPs MEP it is used to suppresses alarms due to CC failure

6. © 2006 Cisco Systems, Inc. All rights reserved.Cisco ConfidentialPresentation_ID 6 Link Down Indication (LDI) LDI must be sent whenever the server layer enters a down state When LDI is received by an MPLS-TP LSPs MEP it is used to Suppresses alarms due to any CC failure If no CC failure has occurred (i.e. BFD is up), transition BFD to down with a diag Path Down Note: the above behaviors are examples and are not specified in this draft

7. © 2006 Cisco Systems, Inc. All rights reserved.Cisco ConfidentialPresentation_ID 7 Indicates that the Tunnel or Link has been Administratively Locked and is unavailable to carry client traffic Otherwise same as LDI Lock Report (LKR)

8. © 2006 Cisco Systems, Inc. All rights reserved.Cisco ConfidentialPresentation_ID 8 New ACH Codepoint with TLV Header 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+- +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 1|Version| Reserved | 0xHH MPLS-TP Fault Management | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ACH TLV Header | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ~ ~ zero or more ACH TLVs ~ ~ | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ~ ~ MPLS-TP Fault Message ~ ~ | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

9. © 2006 Cisco Systems, Inc. All rights reserved.Cisco ConfidentialPresentation_ID 9 AIS, LDI and LKR message format 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+- +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Vers |Flgs |R| OpCode | Refresh Timer | Total TLV Len | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | TLVs | ~ ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ OpCode = AIS, LDI or LKR R-flag indicates removal of the fault Refresh time indicates frequency of transmission

10. © 2006 Cisco Systems, Inc. All rights reserved.Cisco ConfidentialPresentation_ID 10 ACH TLVs Optionally carries Global-ID or ICC Optionally carries IF_ID of failed interface

11. © 2006 Cisco Systems, Inc. All rights reserved.Cisco ConfidentialPresentation_ID 11 Default sending behavior OpCode set to AIS, LDI or LKR R-flag set to zero (not used) Refresh Timer set to a default value Message continuously transmitted until condition clears

12. © 2006 Cisco Systems, Inc. All rights reserved.Cisco ConfidentialPresentation_ID 12 OpCode set to AIS, LDI or LKR R-flag set to zero Refresh Timer set to configured value Message transmitted three times at one second intervals Message continuously transmitted according to refresh timer until condition clears Optional Behavior

13. © 2006 Cisco Systems, Inc. All rights reserved.Cisco ConfidentialPresentation_ID 13 Used when refresh timer is set long When fault / lock condition clears Set R-bit to one Transmit three times at refresh interval of 1 sec Optional Clearing Behavior

14. © 2006 Cisco Systems, Inc. All rights reserved.Cisco ConfidentialPresentation_ID 14 Transitioning from AIS to LDI If the optional sending procedures are being used, the same procedures apply to LDI The LDI message is transmitted three times at one second intervals before falling back to the advertised refresh interval There is no need to clear the AIS message

15. © 2006 Cisco Systems, Inc. All rights reserved.Cisco ConfidentialPresentation_ID 15 Suppress alarms due to BFD Optionally propagate the Alarm (next slide) Note: propagation to TP LSPs is post phase 1 (as we are not supporting hierarchical MPLS-TP Tunnels in phase 1) Receiving AIS

16. © 2006 Cisco Systems, Inc. All rights reserved.Cisco ConfidentialPresentation_ID 16 Next Steps Adopt as a work group draft Polish