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MPLS-TP BFD for CC-CV proactive and RDI functionalities. draft-asm-mpls-tp-bfd-cc-cv-01 MPLS WG, 76th IETF - Hiroshima, Japan. MPLS-TP 76th IETF - Hiroshima. 1. Authors. Annamaria Fulignoli (Ericsson) Sami Boutros (Cisco Systems ) Martin Vigoureux (Alcatel-Lucent). From IETF75.
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MPLS-TP BFD for CC-CV proactive and RDI functionalities draft-asm-mpls-tp-bfd-cc-cv-01 MPLS WG, 76th IETF - Hiroshima, Japan MPLS-TP 76th IETF - Hiroshima 1
Authors • Annamaria Fulignoli (Ericsson) • Sami Boutros (Cisco Systems ) • Martin Vigoureux (Alcatel-Lucent)
From IETF75 • Merging announcement of the 2 existing drafts • draft-fulignoli-mpls-tp-bfd-cv-proactive-and-rdi • draft-boutros-mpls-tp-cc-cv • into draft-asm-mpls-tp-bfd-cc-cv
Goals of draft • Extend BFD for proactive Connection Verification and Reverse Defect Indication • Remain Backwards Compatible • Specify Interoperability
Requirements • Continuity Check: monitors the integrity of the continuity of the path; • Connectivity Verification: monitors the integrity of the routing of the path between sink and source • Detect unintended connectivity (e.g. mismerging or misconnection) • RDI: enable an End Point to report a fault or defect condition that it detects on a PW, LSP or Section • MUST operate proactively for: • bidirectional and unidirectional p2p • unidirectional p2mp connection
Solution Overview • Two modes of operation • CC • Existing ACH codepoint (0x0007) - BFD w/o IP/UDP • Supports CC & RDI • CV/CC • New ACH codepoint • Header contains the Source MEP Identifier (unique per transport path) • BFD control packet format is identical to CC mode • Supports CV & RDI (Implicit CC) • Both apply to PWs, MPLS LSPs (including tandem connection monitoring), and sections
Overview Operating mode is Asynchronous BFD state machine is defined in draft-ietf-bfd-base-09 for p2p bidirectional transport and in draft-katz-ward-bfd-multipoint-02 for unidirectional p2p and p2mp transport path. BFD session is declared Down if : an unexpected MEP identifier is received (mis-connectivity defect; in CV mode only) timer and detect multiplier re-negotiation is disabled and an unexpected desired min Tx interval field value or unexpected detect multiplier field are received (Unexpected period defect). BFD session times out (Loss of Connectivity defect) 7
BFD Session in MPLS-TP terminology • A BFD session corresponds to a CC or a proactive CV/CC OAM instance in MPLS-TP terminology. • A BFD session is enabled when the CC or proactive CV/CC functionality is enabled on a configured Maintenance Entity (ME). • An enabled BFD session can be in DOWN, INIT or UP state • When on a ME the CC or proactive CV/CC functionality is disabled, the BFD session transits in the ADMIN DOWN State and the BFD session ends. • A new BFD session is initiated when the operator enables or re-enables the CC or CV/CC functionality on the same ME.
Default Behavior both CC and CV mode • Active Role is default, passive is optional • BFD timer values are set as follows • Timer and detect multiplier re-negotiation is optional and disabled by default • The configured packet transmission is carried in “Desired Min TX Interval field” • Bidirectionalp2p settings: • “Required Min RX Interval field” MUST be the same as “Desired Min TX Interval field” • Unidirectional p2p and p2mp session MUST set the “Required Min RX Interval field“ to 0 • The session will NOT reach UP if expected timers values and detect multiplier are not the same
BFD packets exchange (To be added to draft) Between MPLS-TP/MPLS nodes • Will be adding scenarios describing: • BFD packets exchange between a regular MPLS node , running ACH encapsulated BFD, and MPLS-TP node. • BFD packets exchange between an MPLS-TP node and another MPLS-TP node.
Next Steps • Add more implementation details: • Behaviour of MEP receiving a BFD packet with AdminDown State • Diagnostic Code supported • Address comments received • Ask for workgroup adoption
QUESTIONS ? THANK YOU