1. draft-sitaraman-mpls-rsvp-shared-labels-00
Signaling RSVP-TE tunnels on a shared MPLS forwarding plane draft-sitaraman-mpls-rsvp-shared-labels-00
Harish Sitaraman
Vishnu Pavan Beeram
Tejal Parikh

2. draft-sitaraman-mpls-rsvp-shared-labels-00
Motivation
Couple the feature benefits of the RSVP-TE control plane with the simplicity of the SR MPLS forwarding plane.
Prevent the platform specific label space limit on an LSR from being a constraint to pushing the limits of control plane scaling on that node.
[ietf-teas-rsvp-te-scaling-rec] proposes guidelines for scaling RSVP-TE control plane.

3. RSVP-TE + SR MPLS forwarding plane
draft-sitaraman-mpls-rsvp-shared-labels-00
RSVP-TE + SR MPLS forwarding plane
Shared forwarding plane
Transit label on a TE link is shared among RSVP-TE tunnels traversing the link.
Forwarding plane state at an LSR
Reduced to roughly = number of RSVP neighbors
Tunnel setup time
Forwarding plane state is not programmed during LSP setup and teardown.
Share labels across MBB
Labels and routes do not change during make-before-break (MBB) on path overlap.
Use all existing RSVP-TE control plane features
FRR, admission control, preemption, auto-bandwidth etc.

4. Allocation of pop labels
draft-sitaraman-mpls-rsvp-shared-labels-00
Allocation of pop labels
Pop and forward label action
Existing operation
LSR SHOULD allocate a unique pop label for each TE link
Install the label route
Label forwarding action: pop and forward to that neighbor
Additional label per TE link necessary for facility backup link protection.

5. RSVP-TE pop and forward tunnel
draft-sitaraman-mpls-rsvp-shared-labels-00
RSVP-TE pop and forward tunnel
RSVP-TE tunnel T1: From A to E on path A-B-C-D-E
RSVP-TE tunnel T2: From F to E on path F-B-C-D-E T1 T2
LSP_ATTRIBUTES/LSP_REQUIRED_ATTRIBUTES in Path message
Attributes Flags TLV: Pop Label
RRO Label Subobject Flag
Pop Label
Shares all labels
150
200
250
100 A
100 B
150 C
200 D
250 E
450
550
650
850
400
500
600
800
150
200
250 F G H I
100
300
350
700

6. Delegation of label stack imposition
draft-sitaraman-mpls-rsvp-shared-labels-00
Delegation of label stack imposition
RSVP-TE pop and forward tunnel from A to J
Explicit/automatic selection of Label Stack delegation points: D and G
HOP_ATTRIBUTES subobject
Attributes TLV: Label Stack Imposition TLV
350
650 A
100 B
200 C
300 D
400 E
500 F
600 G
700 H
800 I
900 J
200
300
350
500
600
650
800
900
100

7. Mixing pop and swap labels
draft-sitaraman-mpls-rsvp-shared-labels-00
Mixing pop and swap labels
RSVP-TE pop and forward tunnel from A to J Hops D and G do not support allocation of pop labels Local logic at ingress to construct label stack based on type of label received (in RRO) from each transit hop
350
650 A
100 B
200 C
300 D E
500 F
600 G H
800 I
900 J
200
300
350
600
650
900
100

8. Facility backup link protection
draft-sitaraman-mpls-rsvp-shared-labels-00
Facility backup link protection
RSVP-TE pop and forward tunnel T1: From A to E on path A-B-C-D-E
At LSR B:
Primary: Pop label 151 and forward via B-C link
Backup: Pop label 151 and send via facility backup to C
151
201
251
100
101
100
151
150
201
200
251
250 A B C D E
450
550
650
850
400
500
600
800 F G H I
300
350
700

9. Next Steps Request WG feedback
draft-sitaraman-mpls-rsvp-shared-labels-00
Next Steps
Request WG feedback
Update the draft with feedback and experience from prototype
Add sections for
Automatic delegation of label stack imposition
Node protection