1. MPLS-TP Shared Mesh Protection draft-cheung-mpls-tp-mesh-protection-05 IETF 83 – Paris, March 2012 Taesik Cheung and Jeong-dong Ryoo (ETRI) Yaacov Weingarten and Nurit Sprecher (NSN) Daniel King (Old Dog)

2. Main Points of Solution Utilizes the existing linear protection as is – No modification needed in the state transition tables – Only the additional coordination actions for SMP are defined in this draft One LSP for each protection path – Each LSP has end-to-end OAM/PSC channel Parallel coordination of protection segments – Use SPMEs for direct communication – Minimize coordination processing time Immediate traffic switchover – Rapid failover as fast as linear protection

3. Changes from 04 Block function at the SEN was added. – To reduce possible congestion during pre-emption – SEN blocks protection LSP to be pre-empted and sends Lockout of Protection (LoP) request. – When an end node of the protection LSP completes the LoP operation, it will send an acknowledge to SEN. – SEN unblocks protection LSP when it receives the LoP Ack. SMP protocol message format was defined. – Initial definition The mechanism was described more in detail. Editorial changes

4. SMP protocol message format Version1 Mode0 – Bidirectional 1 – Unidirectional Type1 – PS Event 2 – LoP Request 3 – LoP Ack 4 – RA Notification 5 – RA Ack ST (Sub-type) 0 – Switch to working (for PS Event) or Clear LoP (for LoP Request) 1 – Switch to protection (for PS Event) or Assert LoP (for LoP Request) ID0x01~0xFE – ID value (4b) (2b)(10b)(8b)

5. Next steps Currently, there are multiple drafts regarding SMP. We will continue the discussion with the authors of the other drafts to explore a possibility to develop a single solution optimized for MPLS-TP networks. We kindly ask the WG experts to review our document and provide us feedback.

6. Protocol Messages Blue: Linear protection protocol messages Red: PS Event (EN  SEN) Orange (solid / dotted): RA Notification / Ack (SEN  SSN) Green (solid / dotted): LoP Request / Ack (SEN/SSN  EN) PQRSTU CDEFGH AB [ Priority: P1>P2>P3>P4 ] P2 P1P3P4 X SF (A  B) W2 W1W3W4 [Acronyms] PS: Protection Switching RA: Resource Allocation LoP: Lockout of Protection EN: End Node SEN: Shard End Node SSN: Shared Start Node Backup slides

7. Principle of Operation End node detecting failure initiates protection – Starts linear protection and sends PS Event to SEN SEN coordinates use of shared resource – Sends RA Notification to SSN (and waits for RA Ack from SSN) – Blocks the equal or lower priority protection LSP – Sends LoP Request to the end node of the protection LSP – Unblocks the protection LSP when it receives LoP Ack SSN coordinates use of shared resource – Sends RA Ack to SEN – Same procedures with SEN (step 2-4) Backup slides

8. Example 1 (SF at high priority LSP) Procedures – A detects SF, sends PS Event to P and starts linear protection. – P blocks P2, sends LoP Request to C and RA Notification to Q. – Q blocks P2 and sends LoP Request to D (and replies RA Ack to P). – C and D perform LoP and send LoP Ack to P and Q. – P and Q unblock P2. A PQ B CD [ Normal ] W1 P1 P2 W2 A PQ B CD [ Protection ] X 1. SF (A  B) W1 P1 P2 W2 Priority P1 > P2 Lockout Backup slides

9. Example 2 (SF at low priority LSP) Procedures – C detects SF, sends PS Event to P and starts linear protection. – P does nothing. A PQ B CD A PQ B CD X 1. SF (C  D) [ Normal ] W1 P1 P2 W2 [ Protection ] W1 P1 P2 W2 Backup slides

10. Example 3 (Pre-emption) Procedures (continued from Example 2) – A detects SF, sends PS Event to P and starts linear protection. – P blocks P2, sends LoP Request to C and RA Notification to Q. – Q blocks P2, sends LoP Request to D (and replies RA Ack to P). – C and D perform LoP and send LoP Ack to P and Q. (return to failed W2) – P and Q unblock P2. A PQ B CD [ P2 occupies P-Q ] W1 P1 P2 W2 A PQ B CD [ P2 pre-empted ] X 2. SF (A  B) W1 P1 P2 W2 Priority P1 > P2 X 1. SF (C  D) X X Lockout Backup slides

11. Example 4 (Equal priority) Procedures (First come, first served) – A detects SF, sends PS Event to P and starts linear protection. – P sends RA Notification to Q and waits for reply. – Q blocks P2, sends LoP Request to D and replies RA Ack to P. – P blocks P2 and sends LoP Request to C. – C and D perform LoP and send LoP Ack to P and Q. – P and Q unblock P2. A PQ B CD [ Normal ] W1 P1 P2 W2 A PQ B CD [ Protection ] X 1. SF (A  B) W1 P1 P2 W2 Priority P1 = P2 Lockout Backup slides

12. Example 5 (Race condition) Procedures (Equal priority resolved by Protection path ID) – B and C detect SF, send PS Event to Q and P and start linear protection. – Q and P send RA Notification to each other and wait for reply. – P blocks P2, sends LoP Request to C and replies RA Ack to Q. – Q blocks P2 and sends LO Request to D. – C and D perform LoP and send LO Ack to P and Q. (return to failed W2) – P and Q unblock P2. A PQ B CD [ Normal ] W1 P1 P2 W2 A PQ B CD [ Protection: P2 rejected ] W1 P1 P2 W2 Priority P1 = P2 (ID1 > ID2) X 1. SF (C  D) X Lockout X 1. SF (A  B) Backup slides