1. Applicability of PCE for Computing Protection Paths draft-chen-pce-protection-applicability Huaimo Chen, Huawei

2. Page 2 Introduction  Discussions initiated by Daniel King on List.  Applications such as Cloud drive increasingly more traffic across longer ranges over LSP crossing domains  It is very important to provide protections for the traffic against failures  PCE is used for computing paths for LSP crossing domains  PCE COULD also be used for computing protection paths for LSP crossing domains

3. Page 3 Many Application Scenarios  End to end disjoint path P2P disjoint path from an ingress to an egress P2MP disjoint path from an ingress to a number of egresses  Multi-homing end to end disjoint path P2P disjoint path from a backup ingress to a backup egress P2MP disjoint path from a backup ingress to a number of backup egresses  One to one Local Protection Path P2P  Path for link protection  Path for intermediate node protection  Path for ingress and egress protection P2MP  Facility Local Protection Path P2P  Path for protecting a set of LSPs over a link  Path for protecting a set of LSPs through an intermediate node  Path for protecting a set of LSPs via ingress and egress P2MP

4. Page 4 PCE for Computing E2E Disjoint Path  P2P disjoint path from an ingress to an egress AU T Q R L M N K J I H G E F C B S P D PCE1 PCE2 PCE3 PCE4 Egress Ingress Primary path from A to U Backup path from A to U, disjoint with the primary path disjoint link, node, domain except for ingress A and egress U

5. Page 5 PCE for Computing E2E Disjoint Path  P2MP disjoint path from an ingress to multiple egresses AY W Q V L M N K J I H G E F C B X P D PCE1 PCE2 PCE3 PCE5 Egress Ingress Primary path from A to U,Y, Z Backup path from A to U,Y and Z, disjoint with the primary path Possible disjoint link, node, domain except for ingress A and egresses U, Y and Z U T R S PCE4 Z B1 A1 C1 PCE6 Egress

6. Page 6 PCE for Multi-homing E2E Disjoint Path  P2P disjoint path from a backup ingress to a backup egress A U Q R L M N K J I H G E F C B SP D PCE1 PCE2 PCE3 PCE4 Egress Ingress Primary path from A to U Backup path from A’ to U’, disjoint with primary path disjoint every link, every node, domain A’A’ U’U’ Backup Ingress Backup Egress T Src Dst

7. Page 7 PCE for Multi-homing E2E Disjoint Path  P2MP disjoint path from an ingress to multiple egresses Y W Q V L M N K J I H G E F C B X P D PCE1 PCE2 PCE3 PCE5 Egress Primary path from A to U,Y, Z Backup path from A’ to U’,Y’ and Z’, disjoint with the primary path Disjoint as many link, node, domain as possible U T R S PCE4 Z B1 A1 C1 PCE6 Egress A Ingress A’A’ Src Z’ U’U’ Y’ Backup Ingress Backup Egress Dst

8. Page 8 PCE for P2P Detour Local Protection Path  Link protection AU T Q R L M N K J I H G E F C B P D PCE1 PCE2 PCE3 PCE4 Egress Ingress P2P LSP from A to U Detour path for protecting link C--F S V C1 Detour path for protecting link J--R

9. Page 9 PCE for P2P Detour Local Protection Path  Intermediate node protection AU T Q R L M N K J I H G E F1F1 C B P D PCE1 PCE2 PCE3 PCE4 Egress Ingress P2P LSP from A to U Detour path for protecting node F S V C1 Detour path for protecting node J

10. Page 10 PCE for P2P Detour Local Protection Path  P2P path for protecting ingress and egress A U Q R L M N K J I H G E F C B SP D PCE1 PCE2 PCE3 PCE4 Egress Ingress P2P LSP from A to U Backup path from A’ to B (NH of A) for protecting ingress A A’A’ U’U’ Backup Ingress Backup Egress T Src Dst Backup path from R (PH of U) to U’ for protecting egress U

11. Page 11 PCE for P2MP Detour Local Protection Path  Path for protecting link  Path for protecting intermediate node  Path for protecting ingress and egress

12. Page 12 PCE for P2P Facility Local Protection Path  Link protection AU T Q R L M N K J I H G E F1F1 C B P D PCE1 PCE2 PCE3 PCE4 Egress Ingress P2P LSP from A to U Facility path for protecting link C— F for 2 LSPs S V C1 Facility path for protecting link J—R for 3 LSPs P2P LSP from A to V Egress W J1J1

13. Page 13 PCE for P2P Facility Local Protection Path  Intermediate node protection AU T Q R L M N K J I H G E F1F1 C B P D PCE1 PCE2 PCE3 PCE4 Egress Ingress P2P LSP from A to U Facility path for protecting node C for 2 LSPs S V C1 P2P LSP from A to V Egress

14. Page 14 PCE for P2P Facility Local Protection Path  P2P path for protecting ingress and egress A U Q R L M N K J I H G E F1F1 C B SP D PCE1 PCE2 PCE3 PCE4 Egress Ingress P2P LSP from A to U Backup path from A’ to B (NH of A) for protecting ingress A for 2 LSPs A’A’ U’U’ Backup Ingress Backup Egress T Src Dst Backup path from R (PH of U) to U’ for protecting egress U for 2 LSPs P2P LSP from A to V Ingress

15. Page 15 PCE for P2MP Facility Local Protection Path  Path for protecting link  Path for protecting intermediate node  Path for protecting ingress and egress

16. Summary/Next Step  Document highlights best practice, use cases and gaps.  Where needed recommendations for further extensions and procedures.  Would this be a useful document for WG?  Please provide input and examples  Thank you!