Dual-Homing Protection for MPLS and MPLS-TP Pseudowires

Weiqiang Cheng, L. Wang, H. Li (China Mobile)K. Liu, J. Dong (Huawei)

S. Davari (Broadcom)A. D'Alessandro (Telecom Italia)

IETF91 PALS Honolulu 2014

Background

• Work was presented in IETF 88 and 90

• Split the draft according to PWE3 chairs’ suggestion:

– Framework and scenarios of dual-homing PW protection

– Protocol extensions for dual-homing protection with static

MPLS-TP PWs

Benefits of Dual-homing Protection

• Local protection– Avoid PW switchover due to AC failure – Avoid AC switchover due to PW failure

• PSN tunnel protection is no longer a MUST

PE Architecture Update

• DNI PW between dual-homing PEs can carry traffic during failure

• Forwarder is responsible for switching traffic between AC,

service PW and DNI PW.

Dual-homing PE Device

Forwarder

DNI PWService PW

Peer Dual-homing PE Device

AC

DNI PW

Service PW

• Can Provide protection for:– AC failure– PE failure– PSN network failure

PE3

PE1

PE2

CE2CE1DNI

PW

linear protection

Working PW

Protection PW

linear protection

AC RedundancyMechanism

dual-homing coordination

Service PW

Service PW

AC1

AC2

One-side Dual-homing Scenario

One-side Dual-homing Scenario

• Can Provide protection for:– AC failure– PSN network failure– PE failure

PE3

PE1

PE2

CE2CE1

1DNIPW

linear protection

Working PW

Protection PW

linear protection

AC RedundancyMechanism

dual-homing coordination

AC1

AC2

One-side Dual-homing Scenario

• Can Provide protection for:– AC failure– PSN network failure– PE failure

PE3

PE1

PE2

CE2CE1

2DNIPW

linear protection

Working PW

Protection PW

linear protection

AC RedundancyMechanism

dual-homing coordination

AC1

AC2

One-side Dual-homing Scenario

• Can Provide protection for:– AC failure– PSN network failure– PE failure

PE3

PE1

PE2

CE2CE1

3

DNIPW

linear protection

Working PW

Protection PW

linear protection

AC RedundancyMechanism

dual-homing coordination

AC1

AC2

Two-side Dual-homing Scenario

• Can Provide protection for:– AC failure– PE failure– PSN network failure

PE3 PE2

CE2 CE1DNIPW

linear protection

Working PW

Protection PW

AC RedundancyMechanism

AC1

AC2

PE3 PE1

linear protection

DNIPW

AC redundancymechanism

43

1

2

5

General Procedures• Dual-homing PEs need to exchange PW state and

switchover coordination request to synchronize the protection switching

• Forwarding behavior of dual-homing PE is determined by:– Status of Service PW– Status of AC– Status of DNI PW

Service PW AC DNI PW Forwarding BehaviorActive Active Up Service PW <-> AC

Active Standby Up Service PW <-> DNI PW

Standby Active Up DNI PW <-> AC

Standby Standby Up Drop all packets

ACService PW

DNI PW

Next Steps

• Solicit comments from WG

• WG adoption?