1. 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 1

2. Authors Annamaria Fulignoli (Ericsson) Sami Boutros (Cisco Systems )
Martin Vigoureux (Alcatel-Lucent)

3. 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

4. Goals of draft
Extend BFD for proactive Connection Verification and Reverse Defect Indication
Remain Backwards Compatible
Specify Interoperability

5. 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

6. 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

7. 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 7

8. 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.

9. 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”
Bidirectional p2p 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

10. 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.

11. Next Steps Add more implementation details: Ask for workgroup adoption
Behaviour of MEP receiving a BFD packet with AdminDown State
Diagnostic Code supported
Address comments received
Ask for workgroup adoption

12. QUESTIONS ?
THANK YOU