introduction to segment routingd2zmdbbm9feqrf.cloudfront.net/2016/usa/pdf/brkrst-2124.pdf ·...

Introduction to Segment Routing

Michael Kowal, Vertical Solutions Architect@ciscomk

BRKRST-2124

© 2016 Cisco and/or its affiliates. All rights reserved. Cisco Public 3BRKRST-2124

Abstract

This session provides an overview of the segment routing technology and its use cases. This new routing paradigm provides high operational simplicity and maximum network scalability and flexibility. You will get an understanding of the basic concepts behind the technology and its wide applicability ranging from simple transport for MPLS services, disjoint routing, traffic engineering and its

benefits in the context of software defined networking. Previous knowledge of IP routing and MPLS is required.

Introduction to Segment Routing

• Technology Overview

• Use Cases

• A Closer Look at the Control and Data Planes

• Traffic Protection

• Traffic Engineering

• Conclusion

Agenda

Technology Overview

© 2016 Cisco and/or its affiliates. All rights reserved. Cisco Public

Segment Routing

• Source Routing– the source chooses a path and encodes it in the packet header as an

ordered list of segments

– the rest of the network executes the encoded instructions

• Segment: an identifier for any type of instruction– forwarding or service

BRKRST-2124 6


Segment Routing – Forwarding Plane

• MPLS: an ordered list of segments is represented as a stack of labels

• IPv6: an ordered list of segments is encoded in a routing extension header

• This presentation: MPLS data plane

BRKRST-2124 7


IGP Prefix Segment

• Shortest-path to the IGP prefix

• Global

• 16000 + Index

• Signaled by ISIS/OSPF

8

DC (BGP-SR)

10

11

12

13

14

2 4

6 5

7

WAN (IGP-SR)

3

1

PEER

16005

BRKRST-2124


IGP Adjacency Segment

• Forward on the IGP adjacency

• Local

• 1XY• X is the “from”

• Y is the “to”

• Signaled by ISIS/OSPF

9

DC (BGP-SR)

10

11

12

13

14

2 4

6 5

7

WAN (IGP-SR)

3

1

PEER

124

BRKRST-2124


BGP Prefix Segment

• Shortest-path to the BGP prefix

• Global

• 16000 + Index

• Signaled by BGP

10

DC (BGP-SR)

10

11

12

13

14

2 4

6 5

7

WAN (IGP-SR)

3

1

PEER

16001

BRKRST-2124


BGP Peering Segment

• Forward to the BGP peer

• Local

• 1XY• X is the “from”

• Y is the “to”

• Signaled by BGP-LS (topology information) to the controller

11

DC (BGP-SR)

10

11

12

13

14

2

6

7

WAN (IGP-SR)

3

1

PEER

Low Lat, Low BW

4

5High Lat, High BW

147

BRKRST-2124


WAN Controller

• SR PCE collects via BGP-LS• IGP segments

• BGP segments

• Topology

12

DC (BGP-SR)

10

11

12

13

14

2 4

6 5

7

WAN (IGP-SR)

3

1

PEER

Low Lat, Low BW

BGP-LS

BGP-LS

BGP-LS

BRKRST-2124

SR

PCE


An end-to-end path as a list of segments

• SR PCE computes that the green path can be encoded as• 16001

• 16002

• 124

• 147

• SR PCE programs a single per-flow state to create an application-engineered end-to-end policy

13

DC (BGP-SR)

10

11

12

13

14

2 4

6 5

7

WAN (IGP-SR)

3

1

PEER

Low Lat, Low BW

50

Default ISIS cost metric: 10

{16001,16002,124,147}

PCEP, Netconf, BGP

BRKRST-2124

SR

PCE


Segment Routing Standardization

• IETF standardization in SPRING working group

• Protocol extensions progressing in multiple groups

• IS-IS

• OSPF

• PCE

• IDR

• 6MAN

• Broad vendor and customer support

14

Sample IETF Documents

Problem Statement and Requirements

(RFC 7855)

Segment Routing Architecture

(draft-ietf-spring-segment-routing)

IPv6 SPRING Use Cases

(draft-ietf-spring-ipv6-use-cases)

Segment Routing with MPLS data plane

(draft-ietf-spring-segment-routing-mpls)

Topology Independent Fast Reroute using Segment Routing

(draft-francois-rtgwg-segment-routing-ti-lfa)

IS-IS Extensions for Segment Routing

(draft-ietf-isis-segment-routing-extensions)

OSPF Extensions for Segment Routing

(draft-ietf-ospf-segment-routing-extensions)

PCEP Extensions for Segment Routing

(draft-ietf-pce-segment-routing)

Close to 40 IETF drafts in progress

BRKRST-2124

https://tools.ietf.org/html/rfc7855

http://tools.ietf.org/html/draft-ietf-spring-segment-routing

http://tools.ietf.org/html/draft-ietf-spring-ipv6-use-cases

https://tools.ietf.org/html/draft-ietf-spring-segment-routing-mpls-04

https://tools.ietf.org/html/draft-francois-rtgwg-segment-routing-ti-lfa-01

http://tools.ietf.org/html/draft-ietf-isis-segment-routing-extensions

http://tools.ietf.org/html/draft-ietf-ospf-segment-routing-extensions

http://datatracker.ietf.org/doc/draft-ietf-pce-segment-routing/


Segment Routing Product Support

• Platforms:

• IOS-XR (ASR9000, CRS-1/CRS-3)

• IOS-XE (ASR1000, CSR1000v, ASR902, ASR903, ISR4400)

• NX-OS (N3K, N9K)

• WAN Automation Engine (WAE)• SR Traffic Engineering

• Integration with NSO

• Upcoming

• NCS5000, NCS6000

15BRKRST-2124

Use Cases


IPv4/6 VPN/Service transport

• IGP only• No LDP, no RSVP-TE

• ECMP

17

1

2 3

4

6 5

7

Site1 Site2

pkt

16007

vpn

pkt

16007

vpn

pkt

pkt

vpn

pkt

BRKRST-2124


Simplest migration: LDP to SR

• Initial state: All nodes run LDP, not SR

18BRKRST-2124

1 LDP

3 4

2

5 6

LDP Domain

LDP LDP

LDP LDP

LDP LDP




• Step1: All nodes are upgraded to SR• In no particular order

• Default label imposition preference = LDP

19BRKRST-2124

1 LDP

3 4

2

5 6

SR+LDP Domain

SR+LDP SR+LDP

SR+LDP SR+LDP

SR+LDP SR+LDP





• leave default LDP label imposition preference

• Step2: All PEs are configured to prefer SR label imposition• In no particular order

20BRKRST-2124

SR+LDP Domain

1 SR

3 4

2

5 6

SR+LDP SR+LDP

SR+LDP SR+LDP

SR+LDP

segment-routing mpls sr-prefer


Simplest migration LDP to SR



• leave default LDP label imposition preference

• Step2: All PEs are configured to prefer SR label imposition• In no particular order

• Step3: LDP is removed from the nodes in the network• In no particular order

• Final state: All nodes run SR, not LDP

21BRKRST-2124

SR Domain

1 SR

3 4

2

5 6

SR SR

SR SR

SR SR


Seamless Interworking with LDP

• Seamless Deployment

22

1

2 3

4

6 5

7

Site1 Site2

pkt

pkt

vpn

pkt

pkt

16007

vpn

pkt

16007

vpn

pkt

vpn

LDP(7)

BRKRST-2124


Topology-Independent LFA (TI-LFA FRR)

• 50msec FRR in any topology

• IGP Automated

• No LDP, no RSVP-TE

• Optimum

• Post-convergence path

• No midpoint backup state

• Detailed operator report• S. Litkowski, B. Decraene, Orange

• Mate Design • How many backup segments

• Capacity analysis

23

1

2 3

4

6 5

7

pkt

16007

16005

pkt

16007

pkt

16007

BRKRST-2124


Automated Traffic Matrix Collection

• Traffic Matrix is fundamental for• capacity planning

• centralized traffic engineering

• IP/Optical optimization

• Most operators do not have an accurate traffic matrix

• With SR, the traffic matrix collection is automated

24

1 2 3 4

1

2

3

4

1

2

4

3

BRKRST-2124


Optimized Content Delivery

• On a per-content, per-user basis, the content delivery application can engineer • the path within the AS

• the selected border router

• the selected peer

• Also applicable for engineering egress traffic from DC to peer• BGP Prefix and Peering Segments

25

1 2

6

4 3

AS1

5

7

AS6AS5

AS7

pkt

16003

16002

126

BRKRST-2124


Application Engineered Routing

• Per-application flow engineering

• End-to-End• DC, WAN, AGG, PEER

• Millions of flows• No signaling

• No midpoint state

• No reclassification atboundaries

26

DC (or AGG)

10

11

12

13

14

Push{16001,

200, 147}

Low-Latency to 7for application A12

2 4

6 5

7

Default ISIS cost metric: 10Default Latency metric: 10

ISIS: 35

WAN

3

1

BSID: 200

200: pop and push {16002,16004}

PEER

Low Lat, Low BW

Low-Lat to 4

PeerSID: 147, Low Lat, Low BW

PeerSID: 147, High Lat, High BW

BRKRST-2124

SR

PCENSO


Application Engineered Routing

• Per-application flow engineering

• End-to-End• DC, WAN, AGG, PEER

• Millions of flows• No signaling

• No midpoint state

• No reclassification atboundaries

27

DC (or AGG)

10

11

12

13

14

Push{16010,

16001,200, 147}

Low-Latency to 7,DC Plane 0 only,for application A12

2 4

6 5

7

Default ISIS cost metric: 10Default Latency metric: 10

ISIS: 35

WAN

3

1

BSID: 200

200: pop and push {16002,16004}

PEER

Low Lat, Low BW

Low-Lat to 4

PeerSID: 147, Low Lat, Low BW

PeerSID: 147, High Lat, High BW

BRKRST-2124

SR

PCENSO

A Closer Look at the Control and Data Planes

© 2016 Cisco and/or its affiliates. All rights reserved. Cisco Public 29

MPLS Control and Forwarding Operation with Segment Routing

PE1 PE2

IGPPE1 PE2

Services

IPv4 IPv6IPv4

VPN

IPv6

VPNVPWS VPLS

Packet

TransportLDP

MPLS Forwarding

RSVP BGP Static IS-IS OSPF

No changes to

control or

forwarding plane

IGP label

distribution for

IPv4 and IPv6.

Forwarding plane

remains the same

MP-BGP

BRKRST-2124


SID Encoding

• Prefix SID

• SID encoded as an index

• Index represents an offset from SRGB base

• Index globally unique

• SRGB may vary across LSRs

• SRGB (base and range) advertised with router capabilities

• Adjacency SID

• SID encoded as absolute (i.e. not indexed) value

• Locally significant

• Automatically allocated for each adjacency

30BRKRST-2124

SRGB = [ 16000 - 23999 ]. Advertised as base = 16,000, range = 7,999

Prefix SID = 16041. Advertised as Prefix SID Index = 41

Adjacency SID = 24000. Advertised as Adjacency SID = 24000

SR-enabled Node


SR IS-IS Control Plane Overview

• IPv4 and IPv6 control plane

• Level 1, level 2 and multi-level routing

• Prefix Segment ID (Prefix-SID) for host prefixes on loopback interfaces

• Adjacency SIDs for adjacencies

• Prefix-to-SID mapping advertisements (mapping server)

• MPLS penultimate hop popping (PHP) and explicit-null label signaling

31BRKRST-2124


router isis DEFAULTnet 49.0001.1720.1625.5001.00address-family ipv4 unicastmetric-style widesegment-routing mpls

!interface Loopback0passiveaddress-family ipv4 unicast!

!interface GigabitEthernet0/0/0/0point-to-pointaddress-family ipv4 unicast!

!!

32BRKRST-2124

Configuring Segment Routing for IPv4 Using IS-IS (Cisco IOS-XR)

Enable Segment Routing for IPv4 with

MPLS data plane


SR OSPF Control Plane Overview

• OSPFv2 control plane

• Multi-area

• IPv4 Prefix Segment ID (Prefix-SID) for host prefixes on loopback interfaces

• Adjacency SIDs for adjacencies

• MPLS penultimate hop popping (PHP) and explicit-null label signaling

33BRKRST-2124


router ospf DEFAULTrouter-id 172.16.255.1segment-routing mplssegment-routing forwarding mplsarea 0interface Loopback0passive

!interface GigabitEthernet0/0/0/0network point-to-point

!!!

34

Configuring Segment Routing for IPv4 Using OSPF (Cisco IOS-XR)

Enable Segment Routing with MPLS

data plane

BRKRST-2124


MPLS Data Plane Operation

• Packet forwarded along IGP shortest path (ECMP)

• Swap operation performed on input label

• Same top label if same/similar SRGB

• PHP if signaled by egress LSR

Payload

SRGB [16,000 – 23,999 ]

X

Payload

Swap

X

Payload

SRGB [16,000 – 23,999 ]

Y

Payload

Pop

Y

Adjacency

SID = X

X

Prefix SID Adjacency SID

Packet forwarded along IGP adjacency

Pop operation performed on input label

Top labels will likely differ

Penultimate hop always pops last adjacency SID

BRKRST-2124


Payload

VPN Label

36

MPLS Data Plane Operation (Prefix SID)

SRGB [16,000 – 23,999 ] SRGB [16,000 – 23,999 ] SRGB [16,000 – 23,999 ] SRGB [16,000 – 23,999 ]

Loopback X.X.X.X

Prefix SID Index = 41

A B C D

Payload

16041

Payload

Push

Push

Swap Pop

Payload Payload

VPN Label

16041

VPN Label

Pop

BRKRST-2124


Payload

VPN Label

37

MPLS Data Plane Operation (Adjacency SIDs)

Payload

16041

Payload

Push

Push

Push

Pop Pop

Payload Payload

VPN Label

16041

VPN Label

Pop

Adjacency

SID = 126

126

A B X D

BRKRST-2124

Loopback X.X.X.X

Prefix SID Index = 41

SRGB [16,000 – 23,999 ] SRGB [16,000 – 23,999 ] SRGB [16,000 – 23,999 ] SRGB [16,000 – 23,999 ]


MPLS LFIB with Segment Routing

• LFIB populated by IGP (ISIS / OSPF)

• Forwarding table remains constant (Nodes + Adjacencies) regardless of number of paths

• Other protocols (LDP, RSVP, BGP) can still program LFIB

38

PE

PE

PE

PE

PE

PE

PE

PE

P

In

Label

Out

Label

Out

Interface

L1 L1 Intf1

L2 L2 Intf1

… … …

L8 L8 Intf4

L9 L9 Intf2

L10 Pop Intf2

… … …

Ln Pop Intf5

Network

Node

Segment Ids

Node

Adjacency

Segment Ids

Forwarding

table remains

constant

BRKRST-2124

Traffic Protection


Topology Independent LFA (TI-LFA) – Benefits

• 100%-coverage 50-msec link and node protection

• Simple to operate and understand• automatically computed by the IGP

• Prevents transient congestion and suboptimal routing• leverages the post-convergence path, planned to carry the traffic

• Incremental deployment• also protects LDP traffic

40BRKRST-2124


Topology Independent LFA – Implementation

• Leverages existing and proven LFA technology• P space: set of nodes reachable from node S (PLR) without using protected link L

• Q space: set of nodes that can reach destination D without using protected link L

• Enforcing loop-freeness on post-convergence path• Where can I release the packet?

At the intersection between the post-convergence shortest path and the Q space

• How do I reach the release point?By chaining intermediate segments that are assessed to be loop-free

41BRKRST-2124


1000

TI-LFA – Zero-Segment Example

• TI-LFA for link R1R2 on R1

• Calculate LFA(s)

• Calculate post-convergence SPT

• Find LFA on post-convergence SPT

• R1 will steer the traffic towards LFA R5

42

Packet to Z

Default metric:10

R5

R2R1

A Z

R3

Packet to Z

R4

R5

Packet to Z

prefix-SID(Z)

BRKRST-2124


TI-LFA – Single-Segment Example


• Calculate P and Q spaces• They overlap in this case


• Find PQ node on post-convergence SPT

• R1 will push the prefix-SID of R4 on the backup path

43

Q-space

P-space

Packet to Z

prefix-SID(Z)

Packet to Z

Packet to Z

prefix-SID(Z)

prefix-SID(R4)

Default metric:10

R5

R2R1

A Z

R3

Packet to Z

R4

BRKRST-2124


TI-LFA – Double-Segment Example


• Calculate P and Q spaces


• Find Q and adjacent P node on post-convergence SPT

• R1 will push the prefix-SID of R4 and the adj-SID of R4-R3 link on the backup path

44

P-space Q-space

1000

Packet to Z

prefix-SID(Z)

Packet to Z

Packet to Z

prefix-SID(Z)

adj-SID(R4-R3)

prefix-SID(R4)

Packet to Z

prefix-SID(Z)

adj-SID(R4-R3)Default metric:10

R5

R2R1

A Z

R3R4 R3R4

Packet to Z

BRKRST-2124

Traffic Engineering


Traffic Engineering with Segment Routing

• Provides explicit routing

• Supports constraint-based routing

• Supports centralized admission control

• No RSVP-TE to establish LSPs

• Uses existing ISIS / OSPF extensions to advertise link attributes

• Supports ECMP

46

TE LSP

Segment

Routing

BRKRST-2124


How Traffic Engineering Works

• Link information Distribution• ISIS-TE

• OSPF-TE

• Path Calculation

• Path Setup

• Forwarding Traffic down path• Auto-route (announce / destinations)

• Static route

• PBR

• PBTS / CBTS

• Forwarding Adjacency

• Pseudowire Tunnel select

47

IP/MPLS

Head end

Mid-point Tail end

TE LSP

BRKRST-2124


Stateful PCE

• PCE maintains topology and path database (established paths)

• More optimal centralized path computation

• Enables centralized path initiation and update control

• Well suited for SDN deployments

48

PCEP

Stateful PCE

TED

LSP DB

PCC

BRKRST-2124


Topology Acquisition

• An external PCE requires some form of topology acquisition

• A PCE may learn topology using BGP-LS, IGP, SNMP, etc.

• BGP-LS characteristics• aggregates topology across one or more domains

• provides familiar operational model

• New BGP-LS attribute TLVs for SR • IGP: links, nodes, prefixes

• BGP: peer node, peer adjacency, peer set

49

Domain 1 Domain 2

Domain 0

BGP-LS

TED

BGP-LS BGP-LS

RR

PCE

BRKRST-2124


Active Stateful PCE

• PCC or PCE may initiate path setup

• PCC may delegate update control to PCE

• PCC may revoke delegation

• PCE may return delegation

50

PCEP

Active Stateful PCE

TED

LSP DB

Stateful

PCC

PCE has update

control over

delegated paths

BRKRST-2124


Active Stateful PCEPCE-Initiated and PCC-Initiated LSPs

• PCE part of controller architecture managing full path life cycle

• Tighter integration with application demands

PCEP

PCC-Initiated (Active Stateful PCE)

TED

LSP DB

Stateful

PCC

PCEP

PCE-Initiated (Active Stateful PCE)

TED

LSP DB

Stateful

PCC

PCC initiates

LSP and

delegates

update

control

PCE initiates

LSP and

maintains

update control

PCC may initiate path setup based on distributed network state

Can be used in conjunction with PCE-initiated paths

BRKRST-2124


PCE Extensions for Segment Routing (SR)• Segment routing enables source routing

based on segment ids distributed by IGP

• PCE specifies path as list of segment ids

• PCC forwards traffic by pushing segment id list on packets

• No path signaling required

• Minimal forwarding state

• Maximum network forwarding virtualization

• The state is no longer in the network but in the packet

• Paths may be PCE- or PCC-initiated

52

PCEP

Segment List:: 10,20,30,40

Stateful PCE

TED

LSP DB

Stateful

PCC

Node

SID

Adjacency

SID

Forwarding

table remains

constant

In Out Int

L1 L1 Intf1

… … …

L7 L7 Int3

L8 Pop Intf3

… … …

L9 Pop Intf5

ApplicationPath

Request

BRKRST-2124

Conclusion


Conclusion

• Simple routing extensions to implement source routing

• Packet path determined by prepended segment identifiers (one or more)

• Data plane agnostic (MPLS, IPv6)

• Network scalability and agility by reducing network state and simplifying control plane

• Traffic protection with 100% coverage with more optimal routing

Recommended Follow-up Session:Segment Routing: Technology and Use-cases (BRKRST-3122)

54BRKRST-2124


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56BRKRST-2124

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© 2016 Cisco and/or its affiliates. All rights reserved. Cisco Public 57BRKRST-2124

Segment Routing Sessions

• Introduction to Segment Routing (BRKRST-2124)

• Segment Routing: Technology and Use-cases (BRKRST-3122)

• Application Engineered Routing: Allowing Applications to Program the Network (BRKSPG-2066)

• Segment Routing in Datacenter using Nexus 9000/3000 (BRKDCN-2050)

• Cisco WAN Automation Engine (WAE) Network Programmability with SR (LTRMPL-2104)

• Segment Routing in Datacenter using Nexus 9000/3000 (LABRST-2020)

• Next Generation Service Provider Network using Segment Routing & BIER (LABSPG-2012)

• DevNet Workshop – Application Engineered Egress Routing (DEVNET-2062)

• DevNet Workshop – Enabling Containers to Leverage SR (DEVNET-2063)

Cisco Live 2016


Continue Your Education

• Demos in the Cisco campus

• Walk-in Self-Paced Labs

• Table Topics

• Meet the Engineer 1:1 meetings

• Related sessions

58BRKRST-2124

Please join us for the Service Provider Innovation Talk featuring:

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Joe Cozzolino | Senior Vice President, Cisco Services

Thursday, July 14th, 2016

11:30 am - 12:30 pm, In the Oceanside A room

What to expect from this innovation talk

• Insights on market trends and forecasts

• Preview of key technologies and capabilities

• Innovative demonstrations of the latest and greatest products

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Register to attend the session live now or

watch the broadcast on cisco.com

Backup Slides


IS-IS Configuration

• Required• Wide metrics

• SR enabled under unicast address family

• Optional• Prefix-SID configured under loopback(s) AF IPv4

• MPLS forwarding enabled automatically on all (non-passive) IS-IS interfaces

• Adjacency-SIDs are automatically allocated for each adjacency

61BRKRST-2124


router isis DEFAULT

net 49.0001.1720.1625.5001.00

address-family ipv4 unicast

metric-style wide

segment-routing mpls

!

interface Loopback0

passive


prefix-sid absolute 16041

!

!

interface GigabitEthernet0/0/0/0

point-to-point


!

!

!

62

Configuring Segment Routing for IPv4 Using IS-IS (Cisco IOS XR)


MPLS data plane

Advertise prefix SID 16041 (index 41) for

Loopback0

BRKRST-2124


router isis DEFAULT

net 49.0001.1720.1625.5001.00


metric-style wide


!

interface Loopback0

passive



!

!


point-to-point


!

!

!

63

Configuring Segment Routing for IPv6 Using IS-IS (Cisco IOS XR)


MPLS data plane


Loopback0

BRKRST-2124


OSPF Configuration

• OSPFv2 control plane

• Required• Enable segment-routing under instance or area(s)

• Command has area scope, usual inheritance applies

• Enable segment-routing forwarding under instance, area(s) or interface(s)• Command has interface scope, usual inheritance applies

• Optional• Prefix-SID configured under loopback(s)

• MPLS forwarding enabled on all OSPF interfaces withsegment-routing forwarding configured

64BRKRST-2124


router ospf DEFAULT

router-id 172.16.255.1


segment-routing forwarding mpls

area 0

interface Loopback0

passive


!


network point-to-point

!

!

!

65

Configuring Segment Routing for IPv4 Using OSPF (Cisco IOS XR)

Enable Segment Routing with MPLS data

plane


Loopback0

BRKRST-2124


router isis DEFAULT

net 49.0001.1720.1625.5001.00


metric-style wide


!

interface Loopback0

passive



!

!



fast-reroute per-prefix

fast-reroute per-prefix ti-lfa

!

!

!

66

Configuring Topology Independent Fast Reroute for IPv4 using Segment Routing and IS-IS (Cisco IOS XR)

Enable TI-LFA for IPv4 prefixes on


BRKRST-2124


router isis DEFAULT

net 49.0001.1720.1625.5001.00


metric-style wide


!

interface Loopback0

passive



!

!



fast-reroute per-prefix

fast-reroute per-prefix ti-lfa

!

!

!

67

Configuring Topology Independent Fast Reroute for IPv6 using Segment Routing and IS-IS (Cisco IOS XR)

Enable TI-LFA for IPv6 prefixes on


BRKRST-2124


router isis DEFAULT

net 49.0001.1720.1625.5001.00


metric-style wide


segment-routing prefix-sid-map receive

segment-routing prefix-sid-map advertise-local

!

...

!

segment-routing

address-family ipv4

prefix-sid-map

172.16.255.1/32 4041 range 8

!

!

!

68

Configuring a Mapping Server for SR and LDP Interworking for IPv4 Using IS-IS (Cisco IOS XR)

Local prefix-to-SID mapping policy

172.16.255.1/32 – 4041

:

172.16.255.8/32 - 4048

Construct active mapping policy using

remotely learned and locally configured

mappings (mapping client)

Advertise local mapping policy (mapping

server)

BRKRST-2124


router isis DEFAULT

net 49.0001.1720.1625.5001.00


metric-style wide


segment-routing prefix-sid-map receive

!

interface Loopback0

passive



!

!


point-to-point


!

!

!

69

Configuring a Mapping Client for SR and LDP Interworking for IPv4 Using IS-IS (Cisco IOS XR)

Construct active mapping policy using

remotely learned and locally configured

mappings (mapping client)

BRKRST-2124


Enabling Segment Routing FeatureNXOS

feature bgp

install feature-set mpls

feature-set mpls

feature mpls l3vpn

feature mpls segment-routing

Under Interface configuration:

mpls ip forwarding

Commands:

BRKRST-2124 70

Thank you