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MPLS SDN 2014 - Topology independant LFA
The document discusses the implementation and benefits of Topology Independent Loop-Free Alternate (TI-LFA) for MPLS networks by Orange. It highlights the requirements for fast reroute capabilities, including complete link and node protection, and presents simulation results from 11 Orange networks indicating the efficiency of TI-LFA in optimizing routing and providing robust service. The conclusion emphasizes TI-LFA's scalability, simplicity, and ability to avoid transient congestion while ensuring optimal paths for network reliability.
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MPLS SDN 2014 - Topology independant LFA
- 1. Topology Independent LFA Orangeuse case & applicability Stéphane Litkowski, Orange Expert Bruno Decraene, Orange Expert MPLS 2014
- 2. 2 TI-LFA Orange BusinessService MPLS 2014 One of the largest dedicated network for business •Worldwide : • 172 countries, 900+ cities •France : • more than 2 million business clients, SMBs and companies in France IP VPN Ethernet Internet Cloud Voice & Telepresence High value: availability, security, SLA
- 3. 3 TI-LFA MPLS2014 Agenda Requirements Topology Independent LFA Applicability on Orange topologies Simulation results
- 4. 4 TI-LFA MPLS2014 Agenda Requirements Topology Independent LFA Applicability on Orange topologies Simulation results
- 5. 5 TI-LFA MPLS2014 Why using Fast Reroute ? Fast convergence is below 1sec BUT: – hard to have the same performance on all nodes – hard to maintain convergence time while network is growing Applications are more and more sensitive (VoIP, CRM, Sync, transport) Customers do not want to rewrite or customize their applications code to handle network failures
- 6. 6 TI-LFA FRR issue MPLS2014MPLS 2014MPLS 2014
- 7. 7 TI-LFA FRR issuePrimary path MPLS 2014MPLS 2014MPLS 2014 South East 5ms
- 8. 8 TI-LFA FRR issuePrimary path Backup path MPLS 2014MPLS 2014MPLS 2014 South East 8ms
- 9. 9 TI-LFA MPLS2014 FRR issue MPLS 2014MPLS 2014
- 10. 10 TI-LFA MPLS2014 FRR issue MPLS 2014MPLS 2014 Primary path 5ms
- 11. 11 TI-LFA MPLS2014 FRR issue MPLS 2014MPLS 2014
- 12. 12 TI-LFA MPLS2014 FRR issue MPLS 2014MPLS 2014 FRR 33ms
- 13. 13 TI-LFA Backup 8ms MPLS 2014 FRRissue MPLS 2014MPLS 2014 FRR 33ms
- 14. 14 TI-LFA Backup 8ms MPLS 2014 FRRissue MPLS 2014MPLS 2014 FRR 33ms COMPLETELY UNOPTIMAL !!!!
- 15. 15 TI-LFA Backup 8ms MPLS 2014 FRRissue MPLS 2014MPLS 2014 FRR 33ms COMPLETELY UNOPTIMAL !!!! DAMAGE NETWORK
- 16. 16 TI-LFA Backup 8ms MPLS 2014 FRRissue MPLS 2014MPLS 2014 FRR 33ms COMPLETELY UNOPTIMAL !!!! DAMAGE NETWORKDAMAGE CUSTOMER SERVICE
- 17. 17 TI-LFA Backup 8ms MPLS 2014 FRRissue MPLS 2014MPLS 2014 FRR 33ms COMPLETELY UNOPTIMAL !!!! DAMAGE NETWORKDAMAGE CUSTOMER SERVICEFRR
- 18. 18 TI-LFA MPLS2014 How to improve ? Requirements – 100% coverage link and node protection – No transient congestion – Optimal routing – Simple solution to operate and understand – Scalable solution
- 19. 19 TI-LFA MPLS2014 What is the more optimal and natural path upon a failure ? Post-convergence path from the PLR Benefits of using Postconvergence path : – Policy compliant and optimized – Well sized – Well known D S Potential backup Path Postconvergence Path How to use Post-convergence path for FRR ? How to improve ?
- 20. 20 TI-LFA Agenda Requirements Topology Independent LFA Applicability on Orange topologies Simulation results
- 21. 21 TI-LFA Providing100% coverage (node/link/SRLG) Segment Routing Fast-Reroute solution – SR allows to use « unlimited » number of paths encoding any FRR path by using Segment Routing blocks : – any Service Provider policy (LFA policy framework) – including post-convergence path as new criteria Primary traffic does not require to be SR : – IP or LDP can be protected by SR MPLS 2014 Topology Independent LFA
- 22. 22 TI-LFA MPLS2014 Topology Independent LFA Cannot use a strict only Explicit Path due to depth of segment stack We need to compress the stack Done by reusing rLFA/dLFA building blocks (P & Q space) S R1 R2 R3 D R4 R5 R6 MPLS MPLS MPLS MPLS 2 MPLS AdjR5 AdjR6 AdjR3 MPLS AdjR6 AdjR3 MPLS AdjR3 MPLS Primary TI-LFA
- 23. 23 TI-LFA MPLS 2014 TopologyIndependent LFA FRR path is computed as follows : – Compute postconvergence shortest path (new SPF) – Enforce loop-freeness by : – finding a P node on the path – finding a Q node on the path after P (P and Q may be equal) – Only P to Q path would be explicit and may be additionnaly compressed using nodal segments S R1 R2 R3 D R4 R5 R6 MPLS MPLS 2 MPLS NodeR5 MPLS NodeR5 MPLS MPLS PQ S R1 R2 R3 D R4 R5 R6 MPLS MPLS 2 MPLS NodeR5 MPLS MPLS MPLS P 50 Q AdjR6 NodeR5 AdjR6 AdjR6
- 24. 24 TI-LFA MPLS2014 Agenda Requirements Topology Independent LFA Applicability on Orange topologies Simulation results
- 25. 25 TI-LFA Analysis ontopologies : case #1 TI-LFA for path optimality Paris Paris Paris Paris STR STR Dijon Lyon Lyon Paris Lyon Poitiers Primary MPLS 2014 Paris Out of transit node
- 26. 26 TI-LFA Analysis ontopologies : case #1 TI-LFA for path optimality Paris Paris Paris Paris STR STR Dijon Lyon Lyon Paris Lyon Poitiers Primary MPLS 2014 Paris Out of transit node
- 27. 27 TI-LFA Analysis ontopologies : case #1 TI-LFA for path optimality Paris Paris Paris Paris STR STR Dijon Lyon Lyon Paris Lyon Poitiers Primary Backup MPLS 2014 Paris Out of transit node
- 28. 28 TI-LFA MPLS2014 Analysis on topologies : case #1 TI-LFA for path optimality Paris Paris Paris Paris STR STR Dijon Lyon Lyon Paris Lyon Poitiers FRR path Paris Out of transit node
- 29. 29 TI-LFA MPLS2014 Analysis on topologies : case #1 TI-LFA for path optimality Paris Paris Paris Paris STR STR Dijon Lyon Lyon Paris Lyon Poitiers MRT FRR path Paris Out of transit node
- 30. 30 TI-LFA MPLS2014 Analysis on topologies : case #1 TI-LFA for path optimality Paris Paris Paris Paris STR STR Dijon Lyon Lyon Paris Lyon Poitiers MRT FRR path RSVP-TE link protection (1:n) Paris Out of transit node
- 31. 31 TI-LFA MPLS2014 Analysis on topologies : case #1 TI-LFA for path optimality Paris Paris Paris Paris STR STR Dijon Lyon Lyon Paris Lyon Poitiers LFA MRT FRR path RSVP-TE link protection (1:n) Paris Out of transit node
- 32. 32 TI-LFA Analysis ontopologies : case #1 TI-LFA for path optimality Paris 1 Paris 2 Paris 3 Paris 5 STR STR Dijon Lyon Lyon Paris 4 Lyon Poitiers EPC FRR Nodal EPC stack composed of one segment Protection stack Node_Paris 4 MPLS 2014 Paris Out of transit node
- 33. 33 TI-LFA MPLS2014 Analysis on topologies : case #2 TI-LFA using multiple segments PE1 R1 PE2 R2 R3 R4 R5 R6 R7 PE3 1 7 3 3 3 1 1 1 11 2 100 100 Primary Backup SR Segments
- 34. 34 TI-LFA MPLS2014 Analysis on topologies : case #2 TI-LFA using multiple segments PE1 R1 PE2 R2 R3 R4 R5 R6 R7 PE3 1 7 3 3 3 1 1 1 11 2 100 100 Primary Backup SR Segments
- 35. 35 TI-LFA MPLS2014 Analysis on topologies : case #2 TI-LFA using multiple segments PE1 R1 PE2 R2 R3 R4 R5 R6 R7 PE3 1 7 3 3 3 1 1 1 11 2 100 100 Primary Backup SR Segments
- 36. 36 TI-LFA MPLS2014 Analysis on topologies : case #2 TI-LFA using multiple segments PE1 R1 PE2 R2 R3 R4 R5 R6 R7 PE3 1 7 3 3 3 1 1 1 11 2 100 100 Primary Backup SR Segments P Q
- 37. 37 TI-LFA MPLS2014 Analysis on topologies : case #2 TI-LFA using multiple segments PE1 R1 PE2 R2 R3 R4 R5 R6 R7 PE3 1 7 3 3 3 1 1 1 11 2 100 100 Primary Backup SR Segments P QProtection stack (PQ) Adj_R3 Adj_R4 Adj_R6 Adj_R7 Adj_PE3 Top Bottom
- 38. 38 TI-LFA MPLS2014 Analysis on topologies : case #2 TI-LFA using multiple segments PE1 R1 PE2 R2 R3 R4 R5 R6 R7 PE3 1 7 3 3 3 1 1 1 11 2 100 100 Primary Backup SR Segments Protection stack compressed P QProtection stack (PQ) Adj_R3 Adj_R4 Adj_R6 Adj_R7 Adj_PE3 Top Bottom
- 39. 39 TI-LFA MPLS2014 Analysis on topologies : case #2 TI-LFA using multiple segments PE1 R1 PE2 R2 R3 R4 R5 R6 R7 PE3 1 7 3 3 3 1 1 1 11 2 100 100 Primary Backup SR Segments Protection stack compressed Node_R3 P QProtection stack (PQ) Adj_R3 Adj_R4 Adj_R6 Adj_R7 Adj_PE3 Top Bottom Top Nodal to R3 Nodal to PE3
- 40. 40 TI-LFA MPLS2014 Analysis on topologies : case #2 TI-LFA using multiple segments PE1 R1 PE2 R2 R3 R4 R5 R6 R7 PE3 1 7 3 3 3 1 1 1 11 2 100 100 Primary Backup SR Segments Nodal to PE3 Protection stack compressed Node_R3 Node_PE3 P QProtection stack (PQ) Adj_R3 Adj_R4 Adj_R6 Adj_R7 Adj_PE3 Top Bottom Top Bottom Nodal to R3 Nodal to PE3
- 41. 41 TI-LFA MPLS2014 Analysis on topologies : case #2 TI-LFA using multiple segments PE1 R1 PE2 R2 R3 R4 R5 R6 R7 PE3 1 7 3 3 3 1 1 1 11 2 100 100 Primary Backup SR Segments Nodal to PE3 Protection stack compressed Node_R3 Node_PE3 P QProtection stack (PQ) Adj_R3 Adj_R4 Adj_R6 Adj_R7 Adj_PE3 Top Bottom Top Bottom Nodal to R3 Nodal to PE3
- 42. 42 TI-LFA MPLS2014 Analysis on topologies : case #3 Maximum observed stack depth PE1 PE2 R1 R2 R3 R4 R5 R6 10 0 10 0 2 1 2 3 3 1 3 1 3 1000 Primary Backup SR Segments
- 43. 43 TI-LFA MPLS2014 Analysis on topologies : case #3 Maximum observed stack depth PE1 PE2 R1 R2 R3 R4 R5 R6 10 0 10 0 2 1 2 3 3 1 3 1 3 1000 Primary Backup SR Segments
- 44. 44 TI-LFA MPLS2014 Analysis on topologies : case #3 Maximum observed stack depth PE1 PE2 R1 R2 R3 R4 R5 R6 10 0 10 0 2 1 2 3 3 1 3 1 3 1000 P Q Protection stack (PQ) Node_R3 Adj_R4 Adj_R5 Adj_R6 Adj_PE2 Primary Backup SR Segments Top Bottom
- 45. 45 TI-LFA MPLS2014 Analysis on topologies : case #3 Maximum observed stack depth PE1 PE2 R1 R2 R3 R4 R5 R6 10 0 10 0 2 1 2 3 3 1 3 1 3 1000 P Q Protection stack (PQ) Node_R3 Adj_R4 Adj_R5 Adj_R6 Adj_PE2 Node_R3 Primary Backup SR Segments Top Bottom
- 46. 46 TI-LFA MPLS2014 Analysis on topologies : case #3 Maximum observed stack depth PE1 PE2 R1 R2 R3 R4 R5 R6 10 0 10 0 2 1 2 3 3 1 3 1 3 1000 P Q Protection stack (PQ) Node_R3 Adj_R4 Adj_R5 Adj_R6 Adj_PE2 Node_R5 Node_R3 Primary Backup SR Segments Top Bottom
- 47. 47 TI-LFA MPLS2014 Analysis on topologies : case #3 Maximum observed stack depth PE1 PE2 R1 R2 R3 R4 R5 R6 10 0 10 0 2 1 2 3 3 1 3 1 3 1000 P Q Protection stack (PQ) Node_R3 Adj_R4 Adj_R5 Adj_R6 Adj_PE2 Node_R5 Node_R6 Node_R3 Primary Backup SR Segments Top Bottom
- 48. 48 TI-LFA MPLS2014 Analysis on topologies : case #3 Maximum observed stack depth PE1 PE2 R1 R2 R3 R4 R5 R6 10 0 10 0 2 1 2 3 3 1 3 1 3 1000 P Q Protection stack (PQ) Node_R3 Adj_R4 Adj_R5 Adj_R6 Adj_PE2 Node_R5 Node_R6 Node_R3 Adj_PE2 Primary Backup SR Segments Top Bottom
- 49. 49 TI-LFA MPLS2014 Analysis on topologies : case #3 Maximum observed stack depth PE1 PE2 R1 R2 R3 R4 R5 R6 10 0 10 0 2 1 2 3 3 1 3 1 3 1000 P Q Protection stack (PQ) Node_R3 Adj_R4 Adj_R5 Adj_R6 Adj_PE2 Protection stack compressed Node_R5 Node_R6 Node_R3 Adj_PE2 Primary Backup SR Segments Top Bottom Top Bottom
- 50. 50 TI-LFA MPLS2014 Agenda Requirements Topology Independent LFA Applicability on Orange topologies Simulation results
- 51. 51 TI-LFA MPLS2014 Simulations results on 11 Orange Networks Depth of protection stack 11 topologies have been analyzed including multiple network types and size
- 52. 52 TI-LFA Simulations resultson 11 Orange Networks MPLS 2014 80% of nodes have 12 or less distinct repair_lists
- 53. 53 TI-LFA 100%FRR link/node protection is a requirement Current FRR technics may cause some side effects : – Transient network congestion – Additionnal management for selection of the backup path Topology Independent LFA : – Scalable : no additional state in the network – Simple to compute – Provides 100% link/node protection – Prevents any side effect by using a well sized and optimal path – Simple to understand : well known pathMPLS 2014 Conclusion
- 54.