Advertising MPLS labels in IGPs - - PowerPoint PPT Presentation

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Sep 24, 2022 38 likes •178 views

Advertising MPLS labels in IGPs draft-gredler-rtgwg-igp-label-advertisement IETF86 Hannes Gredler March 2013 <hannes@juniper.net> Motivation and Rationale R-LFA implementation requires IS-IS LDP more tight integration of LDP and

SLIDE 1

Advertising MPLS labels in IGPs

draft-gredler-rtgwg-igp-label-advertisement

Hannes Gredler <hannes@juniper.net> IETF86 March 2013

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Motivation and Rationale

R-LFA implementation requires

more tight integration of LDP and IGP

Bi-directional notification

path between protocols

MPLS transport label distribution

are Session oriented protocols

You need to have a session

with a neighbor in order to receive/distribute bindings

Interesting use cases for >1 hop

distribution of transport labels

LDP IS-IS

IGP Base Topo N3 IGP Base Topo N2

mpls.0 inet.0 inet.3

IGP Base Topo

LDP rslv Base context

IGP Base Topo N1 LFA rt-flash rt rt-flash rt rt rt-backup

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USE CASE #1 INCREASE (R-)LFA COVERAGE

SLIDE 4

Pathologic Topologies

M1 M2 M4 >= M1+M2+M3 Primary forwarding path

D PLR

looped backup traffic M3

E H

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Add one-hop strict forwarding labels (stack ‘em)

M1 M2 Primary forwarding path

D H

Backup tunnel to helper Explicit 1-hop tunnel

IGP advertisement: Neighbor D: label 100 Neighbor E: label 200

M4 >= M1+M2+M3 M3

PLR E

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USE CASE #2 TE BY LABEL-STACKING

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TE by label stacking per-neighbor labels

R3 R4 S R1

2 2 2 1 1 5 5 1

IGP advertisement: Neighbor S: label 100 Neighbor R2: label 102 Neighbor R4: label 104 IGP advertisement: Neighbor R1: label 401 Neighbor R2: label 402 Neighbor R4: label 404 Neighbor D: label 405 IGP advertisement: Neighbor R1: label 201 Neighbor D: label 205 Neighbor R4: label 204

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USE CASE #3 ADVERTISING TE LSPS

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Advertise RSVP LSPs as Forwarding Adjacency Issue: LSP path properties lost

R3 R4 S R1

R6 D R5

1 1 1 1 5 5 5 2 2 2 2 RSVP Tunnel IGP FA

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Advertise existing LSPs & EROs

> Allows path property correlation

R3 R4 S R1

R6 D R5

1 1 1 1 5 5 5 2 2 2 2 RSVP Tunnel

IGP advertisement: Neighbor R1: label 401, ERO (R1) Neighbor R2: label 402, ERO (R2) Neighbor R3: label 403, ERO (R3) Neighbor R6: label 406, ERO (R6) Neighbor R6: label 407, ERO (R2, R6)

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USE CASE #4 EGRESS WAN SDN CONTROL(ER)

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Current TE framework only offers egress Node control.

> No good Egress Link control

AS 2 AS1

R2 ASBR2 S R1

ASBR1

ASBR4 ASBR6 ASBR3

ASBR5

AS 3 91/8 91/8 91/8 91/8

tweak BGP import policy

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SDN ECMP weight controller and per-neighbor label

AS 2 AS1

R2 ASBR2 S R1

ASBR1

ASBR4 ASBR6 ASBR3

ASBR5

AS 3 91/8 91/8 91/8 91/8

SDN controller Traffic stats Traffic stats ECMP weigths

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Next ¡Steps ¡

Yesterday ¡(20130313) ¡submission ¡isis-‑wg ¡

– dra=-‑previdi-‑filsfils-‑isis-‑segment-‑rouAng-‑00 ¡ – Core ¡is ¡adverAsing ¡“segments” ¡for ¡source ¡rouAng ¡ – IGP ¡disseminates ¡“segment” ¡ – Some ¡similariAes ¡(IGP ¡label) ¡ – Some ¡discrepancies ¡(AdverAsing ¡exisAng ¡labels, ¡ Gloab ¡labels) ¡ – Working ¡with ¡authors ¡to ¡assess ¡dra= ¡merge ¡