mpls_te_ospf.pdf

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MPLS Basic Traffic Engineering

Using OSPF Configuration Example

Contents

IntroductionPrerequisites

RequirementsComponents UsedConventions

Functional ComponentsConfigureNetwork DiagramQuick Configuration GuideConfiguration Files

VerifySample show Command Output

TroubleshootRelated Information

Introduction

This document provides a sample configuration for implementing trafficengineering (TE) on top of an existing Multiprotocol Label Switching (MPLS)network using Frame Relay and Open Shortest Path First (OSPF). Our example implements twodynamic tunnels (automatically set up by the ingress Label Switch Routers [LSR]) and two tunnels thatuse explicit paths.

TE is a generic name corresponding to the use of different technologies to optimize the utilization of agiven backbone capacity and topology.

MPLS TE provides a way to integrate TE capabilities (such as those used on Layer 2 protocols likeATM) into Layer 3 protocols (IP). MPLS TE uses an extension to existing protocols (IntermediateSystem-to-Intermediate System (IS-IS), Resource Reservation Protocol (RSVP), OSPF) to calculate andestablish unidirectional tunnels that are set according to the network constraint. Traffic flows aremapped on the different tunnels depending on their destination.

Prerequisites

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Requirements

There are no specific requirements for this document.

Components Used

The information in this document is based on the software and hardware versions:

Cisco IOSSoftware Releases 12.0(11)S and 12.1(3a)T

Cisco 3600 routers

The information in this document was created from the devices in a specific lab environment. All of thedevices used in this document started with a cleared (default) configuration. If your network is live,make sure that you understand the potential impact of any command.

Conventions

Refer to Cisco Technical Tips Conventionsfor more information on document conventions.

Functional Components

The following table describes the functional components of this configuration example:

Component Description

IP tunnelinterfaces

Layer 2: an MPLS tunnel interface isthe head of a Label Switched Path

(LSP). It is configured with a set ofresource requirements, such asbandwidth and priority. Layer 3: theLSP tunnel interface is the head-end ofa unidirectional virtual link to the tunneldestination.

RSVP with TEextension

RSVP is used to establish and maintainLSP tunnels based on the calculatedpath using PATH and RSVPReservation (RESV) messages. TheRSVP protocol specification has been

extended so that the RESV messagesalso distribute label information.

Link-State InteriorGateway Protocol(IGP) [IS-IS orOSPF with TEextension]

Used to flood topology and resourceinformation from the link managementmodule. IS-IS uses new Type-Length-Values (TLVs); OSPF uses type 10Link-State Advertisements (also calledOpaque LSAs).


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Configure

In this section, you are presented with the information to configure the features described in thisdocument.

Note: Use the Command Lookup Tool(registeredcustomers only) to find more information on thecommands used in this document.

Network Diagram

This document uses this network setup:

MPLS TE pathcalculation module

Operates at the LSP head only anddetermines a path using informationfrom the link-state database.

MPLS TE linkmanagement

module

At each LSP hop, this module performslink call admission on the RSVPsignaling messages, and bookkeeping of

topology and resource information to beflooded by OSPF or IS-IS.

Label switchingforwarding

Basic MPLS forwarding mechanismbased on labels.


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Quick Configuration Guide

You can use the following steps to perform a quick configuration. Refer to MPLS Traffic Engineeringand Enhancementsfor more detailed information.

1. Set up your network with the usual configuration. (In this case, we used Frame Relay.)

Note: It is mandatory to set up a loopback interface with an IP mask of 32 bits. This address willbe used for the setup of the MPLS network and TE by the routing protocol. This loopback addressmust be reachable via the global routing table.

2. Set up a routing protocol for the MPLS network. It must be a link-state protocol (IS-IS or OSPF).In the routing protocol configuration mode, enter the following commands:

For IS-IS:


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metric-style [wide | both]mpls traffic-eng router-id LoopbackNmpls traffic-eng [level-1 | level-2 |]

For OSPF:

mpls traffic-eng area Xmpls traffic-eng router-id LoopbackN ( must have a 255. 255. 255. 255 mas

3. Enable MPLS TE. Enter ip cef(or ip cef distributedif available in order to enhanceperformance) in the general configuration mode. Enable MPLS (tag-switching ip) on eachconcerned interface. Enter mpls traffic-engineering tunnel to enable MPLS TE, as well as RSVPfor zero-bandwidth TE tunnels.

4. Enable RSVP by entering ip rsvp bandwidth XXXon each concerned interface for non-zerobandwidth tunnels.

5. Set up tunnels to be used for TE. There are many options that can be configured for MPLS TETunnel, but the tunnel mode mpls traffic-engcommand is mandatory. The tunnel mpls traffic-eng autoroute announcecommand announces the presence of the tunnel by the routing protocol.

Note: Do not forget to use ip unnumbered loopbackNfor the IP address of the tunnel interfaces.

This configuration shows two dynamic tunnels (Pescara_t1 and Pescara_t3) with differentbandwidth (and priorities) going from the Pescara router to the Pesaro router, and two tunnels(Pesaro_t158 and Pesaro_t159) using an explicit path going from Pesaro to Pescara.

Configuration Files

This document uses the configurations shown below. Only the relevant parts of the configuration files

are included. Commands used to enable MPLS are in blue text; commands specific to TE (includingRSVP) are in boldtext.

Pesaro

Cur r ent conf i gur at i on:

!

ver si on 12. 1

!

host name Pesar o

!

ip cef

!


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mpls traffic-eng tunnels

!

i nt er f ace Loopback0

i p addr ess 10. 10. 10. 6 255. 255. 255. 255

!

interface Tunnel158

ip unnumbered Loopback0

tunnel destination 10.10.10.4

tunnel mode mpls traffic-eng

tunnel mpls traffic-eng autoroute announce

tunnel mpls traffic-eng priority 2 2

tunnel mpls traffic-eng bandwidth 158

tunnel mpls traffic-eng path-option 1 explicit name low

!

interface Tunnel159







tunnel mpls traffic-eng path-option 1 explicit name straight

!

i nt er f ace Ser i al 0/ 0

no i p address

encapsul at i on f r ame- r el ay

!

i nt er f ace Seri al 0/ 0. 1 poi nt - t o- poi nt

bandwi dt h 512

i p addr ess 10. 1. 1. 22 255. 255. 255. 252


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tag-switching ip


f r ame- r el ay i nt er f ace- dl ci 603

ip rsvp bandwidth 512 512

!

r out er ospf 9

net work 10. 1. 1. 0 0. 0. 0. 255 ar ea 9

network 10. 10. 10. 0 0. 0. 0. 255 area 9

mpls traffic-eng area 9

mpls traffic-eng router-id Loopback0

!

i p cl assl ess

!

ip explicit-path name low enable

next-address 10.1.1.21




!

ip explicit-path name straight enable




!

end

Pescara


!


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ver si on 12. 0

!

host name Pescar a

!

ip cef

!


!


i p addr ess 10. 10. 10. 4 255. 255. 255. 255

!

interface Tunnel1


no ip directed-broadcast






tunnel mpls traffic-eng path-option 2 dynamic

!

interface Tunnel3


no ip directed-broadcast






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tunnel mpls traffic-eng path-option 1 dynamic

!


no i p address


!


bandwi dt h 512

i p addr ess 10. 1. 1. 14 255. 255. 255. 252


tag-switching ip



!

r out er ospf 9

net work 10. 1. 1. 0 0. 0. 0. 255 ar ea 9

network 10. 10. 10. 0 0. 0. 0. 255 area 9



!

end

Pomerol


ver si on 12. 0

!

host name Pomer ol


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!

ip cef

!


!


i p addr ess 10. 10. 10. 3 255. 255. 255. 255

!


no i p address


!


bandwi dt h 512

i p addr ess 10. 1. 1. 6 255. 255. 255. 252


tag-switching ip


i p rsvp bandwi dth 512 512

!


bandwi dt h 512

i p addr ess 10. 1. 1. 9 255. 255. 255. 252


tag-switching ip




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!


bandwi dt h 512

i p addr ess 10. 1. 1. 21 255. 255. 255. 252


tag-switching ip



!

r out er ospf 9

net work 10. 1. 1. 0 0. 0. 0. 255 ar ea 9

network 10. 10. 10. 0 0. 0. 0. 255 area 9



!

i p cl assl ess

!

end

Pulligny


!

ver si on 12. 1

!

host name Pul l i gny

!

ip cef

!


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!


i p addr ess 10. 10. 10. 2 255. 255. 255. 255

!


no i p address


!


bandwi dt h 512

i p addr ess 10. 1. 1. 2 255. 255. 255. 252


tag-switching ip



!


bandwi dt h 512

i p addr ess 10. 1. 1. 10 255. 255. 255. 252


tag-switching ip



!

r out er ospf 9

net work 10. 1. 1. 0 0. 0. 0. 255 ar ea 9


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tag-switching ip



!


bandwi dt h 512

i p addr ess 10. 1. 1. 5 255. 255. 255. 252


tag-switching ip



!


bandwi dt h 512

i p addr ess 10. 1. 1. 13 255. 255. 255. 252


tag-switching ip



!

r out er ospf 9

net work 10. 1. 1. 0 0. 0. 0. 255 ar ea 9

network 10. 10. 10. 0 0. 0. 0. 255 area 9



!

i p cl assl ess


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Verify

This section provides information you can use to confirm your configuration is working properly.

General show commands are illustrated in Configuring MPLS Basic Traffic Engineering Using IS-IS.The following commands are specific to MPLS TE with OSPF and are illustrated below:

show ip ospf mpls traffic-eng link

show ip ospf database opaque-area

The Output Interpreter Tool(registeredcustomers only) (OIT) supports certain showcommands. Use the

OIT to view an analysis of showcommand output.

Sample show Command Output

You can use the show ip ospf mpls traffic-eng linkcommand to see what will be advertised by OSPFat a given router. The RSVP characteristics are shown in bold below, indicating the bandwidth that canbe reserved, which is being advertised and used. You can see the bandwidth used by Pescara_t1 (atPriority 5) and Pescara_t3 (at Priority 6).

Pesar o# show ip ospf mpls traffic-eng link

OSPF Rout er wi t h I D ( 10. 10. 10. 61) ( Process I D 9)

Ar ea 9 has 1 MPLS TE l i nks. Ar ea i nst ance i s 3.

Li nks i n hash bucket 48.Li nk i s associ at ed wi t h f r agment 0. Li nk i nst ance i s 3

Li nk connect ed to Poi nt - t o- Poi nt net workLi nk I D : 10. 10. 10. 3 Pomer olI nt er f ace Addr ess : 10. 1. 1. 22Nei ghbor Addr ess : 10. 1. 1. 21Admi n Met r i c : 195

Maximum bandwidth : 64000

Maximum reservable bandwidth : 64000

Number of Priority : 8

Priority 0 : 64000 Priority 1 : 64000



Priority 6 : 24000 Priority 7 : 24000Af f i ni t y Bi t : 0x0

The show ip ospf databasecommand can be restrained to Type 10 LSAs and shows the database that isused by the MPLS TE process to calculate the best route (for TE) for dynamic tunnels (Pescara_t1 andPescara_t3 in this example). This can be seen in the following partial output:

Pesar o# show ip ospf database opaque-area

!

end


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OSPF Rout er wi t h I D ( 10. 10. 10. 61) ( Process I D 9)

Type- 10 Opaque Li nk Ar ea Li nk St at es ( Ar ea 9)

LS age: 397Opt i ons: ( No TOS- capabi l i t y, DC)LS Type: Opaque Ar ea Li nk

Li nk St at e I D: 1. 0. 0. 0Opaque Type: 1Opaque I D: 0Adver t i si ng Rout er : 10. 10. 10. 1LS Seq Number : 80000003Checksum: 0x12C9Length: 132Fr agment number : 0

MPLS TE r out er I D : 10. 10. 10. 1 Paui l l ac

Li nk connect ed t o Poi nt - t o- Poi nt net wor kLi nk I D : 10. 10. 10. 3I nt er f ace Addr ess : 10. 1. 1. 5

Nei ghbor Addr ess : 10. 1. 1. 6Admi n Met r i c : 195Maxi mum bandwi dt h : 64000Maxi mumr eservabl e bandwi dt h : 48125Number of Pr i ori t y : 8Pr i or i t y 0 : 48125 Pr i or i t y 1 : 48125Pr i or i t y 2 : 48125 Pr i or i t y 3 : 48125Pr i or i t y 4 : 48125 Pr i or i t y 5 : 16125Pr i or i t y 6 : 8125 Pr i or i t y 7 : 8125Af f i ni t y Bi t : 0x0

Number of Li nks : 1LS age: 339

Opt i ons: ( No TOS- capabi l i t y, DC)LS Type: Opaque Ar ea Li nkLi nk St at e I D: 1. 0. 0. 0Opaque Type: 1Opaque I D: 0Adver t i si ng Rout er : 10. 10. 10. 2LS Seq Number : 80000001Checksum: 0x80A7Length: 132Fr agment number : 0

MPLS TE r out er I D : 10. 10. 10. 2 Pul l i gny

Li nk connect ed t o Poi nt - t o- Poi nt net wor k

Li nk I D : 10. 10. 10. 1I nt er f ace Addr ess : 10. 1. 1. 2Nei ghbor Addr ess : 10. 1. 1. 1Admi n Met r i c : 195Maxi mum bandwi dt h : 64000Maxi mumr eservabl e bandwi dt h : 64000Number of Pr i ori t y : 8Pr i or i t y 0 : 64000 Pr i or i t y 1 : 64000Pr i or i t y 2 : 64000 Pr i or i t y 3 : 64000Pr i or i t y 4 : 64000 Pr i or i t y 5 : 64000Pr i or i t y 6 : 64000 Pr i or i t y 7 : 64000


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Af f i ni t y Bi t : 0x0

Number of Li nks : 1

LS age: 249Opt i ons: ( No TOS- capabi l i t y, DC)LS Type: Opaque Ar ea Li nkLi nk St at e I D: 1. 0. 0. 0

Opaque Type: 1Opaque I D: 0Adver t i si ng Rout er : 10. 10. 10. 3LS Seq Number : 80000004Checksum: 0x3DDCLength: 132Fr agment number : 0

Troubleshoot

There is currently no specific troubleshooting information available for this configuration.

Related Information

MPLS Support Page IP Routing Support Page Technical Support & Documentation - Cisco Systems

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