PW Stitching Procedures in MPLS-TP Networks

draft-boutros-pwe3-ms-pw-tp-00

Sami Boutros Siva Sivabalan

Luca Martini

Background

• This draft extends the PW stitching procedures defined in “draft-ietf-pwe3-segmented-pw-15.txt” to include:-

1. Lock Instruct (LI) and Loopback (LB) OAM functions for MPLS-TP networks specified in“draft-boutros-mpls-tp-li-lb-00.txt”.

2. PW OAM messages for static PWs specified in “draft-ietf-pwe3-static-pw-status-00.txt”.

3. PW static FEC defined in “draft-nitinb-mpls-tp-on-demand-cv-00.txt”.

LI on MPLS-TP LSP (1)

S-PET-PE1 T-PE2

PW

MPLS-TP LSP

PW status can be sent via LDP or PW OAM depending on whether the PW is dynamic or static respectively

If PW status not supported, Label Withdraw method is used

LI Request

LI Reply

1

3

PW status (0x00000018)2

LI on MPLS-TP LSP (2)

S-PET-PE1 T-PE2

PW

MPLS-TP LSP

PW status (0x00000018)

LI Request

LI Reply

Same as the previous case except that LI request originates at S-PE

If LI reply is negative, S-PE sends PW status 0x00000000 to T-PE2 to re-activate PW

2

1

3

LI on PW

S-PET-PE1 T-PE2

PW

MPLS-TP LSP

LI Request

LI Reply

LI request originating from T-PE1 is intended for S-PE. Upon receiving LI request, S-PE relays it to T-PE2.

If S-PE cannot relay LI request to T-PE2, it can use either PW status 0x00000018 or label withdraw method to bring down PW between itself and T-PE2

1

4

LI Request

LI Reply

2

3

LB on MPLS-TP LSP

S-PET-PE1 T-PE2

PW

MPLS-TP LSP

Once MPLS-TP LSP between T-PE1 and S-PE is setup in LB mode, all PW traffic from T-PE1 to S-PE will be looped back to T-PE1

LB Request

LB Reply

1

3

PW status (0x00000018)2

LB on PW

S-PET-PE1 T-PE2

PW

MPLS-TP LSP

Once PW between T-PE1 and S-PE is setup in LB mode, all PW traffic from T-PE1 to S-PE will be looped back to T-PE1

LB Request

LB Reply

1

3PW status (0x00000018)

2

Future Work Align with MPLS-TP drafts Guidance:-

Rename to draft-boutros-pwe3-mpls-tp-ms-pw-00.txt Include the paragraphs in

http://wiki.tools.ietf.org/misc/mpls-tp/wiki/Boilerplate%20for%20MPLS-TP%20Internet-Drafts

Add new sub-TLV type to represent static PW FEC in S-PE TLV