Applicability of PCE for Applicability of PCE for Computing Protection PathsComputing Protection Paths

draft-chen-pce-protection-applicability

Huaimo Chen, Huawei

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

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

Page 4

PCE for Computing E2E Disjoint Path P2P disjoint path from an ingress to an egress

A UT

Q

R

L

M

N

K

J

IH

GE

FC

B

SP

D

PCE1

PCE2

PCE3

PCE4

EgressIngress

Primary path from A to U

Backup path from A to U, disjoint with the primary pathdisjoint link, node, domain except for ingress A and egress U

Page 5

PCE for Computing E2E Disjoint Path P2MP disjoint path from an ingress to multiple egresses

A YW

Q

V

L

M

N

K

J

IH

GE

FC

B

XP

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 pathPossible disjoint link, node, domain except for ingress A and egresses U, Y and Z

UT

R

S

PCE4

ZB1

A1

C1PCE6

Egress

Egress

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

IH

GE

FC

B

SPD

PCE1

PCE2

PCE3

PCE4

Egress

Ingress

Primary path from A to U

Backup path from A’ to U’, disjoint with primary pathdisjoint every link, every node, domain

A’U’

Backup Ingress

Backup Egress

TSrc

Dst

Page 7

PCE for Multi-homing E2E Disjoint Path P2MP disjoint path from an ingress to multiple egresses

YW

Q

V

L

M

N

K

J

IH

GE

FC

B

XP

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 pathDisjoint as many link, node, domain as possible

UT

R

S

PCE4

ZB1

A1

C1PCE6

Egress

Egress

A

Ingress

A’

Src

Z’

U’

Y’

Backup Ingress

Backup Egress

Dst

Dst

Dst

Page 8

PCE for P2P Detour Local Protection Path Link protection

A UT

Q

R

L

M

N

K

J

IH

GE

FC

B

P

D

PCE1

PCE2

PCE3

PCE4

EgressIngress

P2P LSP from A to U

Detour path for protecting link C--F

S

VC1

Detour path for protecting link J--R

Page 9

PCE for P2P Detour Local Protection Path Intermediate node protection

A UT

Q

R

L

M

N

K

J

IH

GE

F1C

B

P

D

PCE1

PCE2

PCE3

PCE4

EgressIngress

P2P LSP from A to U

Detour path for protecting node F

S

VC1

Detour path for protecting node J

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

IH

GE

FC

B

SPD

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’U’

Backup Ingress

Backup Egress

TSrc

Dst

Backup path from R (PH of U) to U’ for protecting egress U

Page 11

PCE for P2MP Detour Local Protection Path Path for protecting link Path for protecting intermediate node Path for protecting ingress and egress

Page 12

PCE for P2P Facility Local Protection Path Link protection

A UT

Q

R

L

M

N

K

J

IH

GE

F1C

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

VC1

Facility path for protecting link J—R for 3 LSPs

P2P LSP from A to V

Egress

W

J1

Page 13

PCE for P2P Facility Local Protection Path Intermediate node protection

A UT

Q

R

L

M

N

K

J

IH

GE

F1C

B

P

D

PCE1

PCE2

PCE3

PCE4

EgressIngress

P2P LSP from A to U

Facility path for protecting node C for 2 LSPs

S

VC1

P2P LSP from A to V

Egress

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

IH

GE

F1C

B

SPD

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’U’

Backup Ingress

Backup Egress

TSrc

Dst

Backup path from R (PH of U) to U’ for protecting egress U for 2 LSPs

P2P LSP from A to V

Ingress

Page 15

PCE for P2MP Facility Local Protection Path Path for protecting link Path for protecting intermediate node Path for protecting ingress and egress

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!