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MPLS LDP Configuration Guide, Cisco IOS Release 12.4 Americas Headquarters Cisco Systems, Inc. 170 West Tasman Drive San Jose, CA 95134-1706 USA http://www.
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C O N T E N T S MPLS Label Distribution Protocol (LDP) 1 Finding Feature Information 1 Prerequisites for MPLS LDP 1 Information About MPLS LDP 1 Introduction to MPLS LDP 2 MPLS LDP Functional Overview.
Enabling MPLS LDP Session Protection 33 Verifying MPLS LDP Session Protection 35 Troubleshooting Tips 36 Configuration Examples for MPLS LDP Session Protection 36 Additional References 39 Command Refe.
MPLS LDP Graceful Restart 65 Finding Feature Information 65 Restrictions 65 Information About MPLS LDP Graceful Restart 66 How MPLS LDP Graceful Restart Works 66 How a Route Processor Advertises That .
Contents MPLS LDP Configuration Guide, Cisco IOS Release 12.4 vi.
MPLS Label Distribution Pr otocol (LDP) Multiprotocol Label Switching (MPLS) Label Distribution Protocol (LDP) enables peer label switch routers (LSRs) in an MPLS network to exchange label binding information for supporting hop-by-hop forwarding in an MPLS network.
Introduction to MPLS LDP MPLS LDP provides the means for LSRs to request, distribute, and release label prefix binding information to peer routers in a network. LDP enables LSRs to discover potential peers and to establish LDP sessions with those peers for the purpose of exchanging label binding information.
Train and Release LDP/TDP Support 12.2S, SB, and SR Trains • LDP is enabled by default. • Cisco IOS Release 12.2(25)S and earlier releases: TDP is supported for LDP features. • Cisco IOS Releases 12.2(27)SBA, 12.2(27)SRA, 12.2(27)SRB and later releases: TDP is not supported for LDP features.
Nondirectly Connected MPLS LDP Sessions If the LSR is more than one hop from its neighbor, it is nondirectly connected to its neighbor. For these nondirectly connected neighbors, the LSR sends out a targeted Hello message as a UDP packet, but as a unicast message specifically addressed to that LSR.
• Platform-wide--An LDP platform supports a single platform-wide label space for use by interfaces that can share the same labels. For Cisco platforms, all interface types, except LC-ATM, use the platform- wide label space. LDP uses a 6-byte quantity called an LDP Identifier (or LDP ID) to name label spaces.
• Establishing Nondirectly Connected MPLS LDP Sessions, page 8 • Saving Configurations MPLS Tag Switching Commands, page 11 • Specifying the LDP Router ID, page 12 • Preserving QoS Settings wi.
Command or Action Purpose Step 4 mpls label protocol {ldp | tdp | both} Example: Router(config)# mpls label protocol ldp Configures the use of LDP on all interfaces.
Command or Action Purpose Step 11 show mpls ldp neighbor [[ vrf vpn-name ] [ address | interface ] [ detail ] | [ all ]] Example: Router# show mpls ldp neighbor Displays the status of LDP sessions.
SUMMARY STEPS 1. enable 2. configure terminal 3. mpls ip 4. mpls label protocol {ldp | tdp | both} 5. interface tunnelnumber 6. tunnel destination ip-address 7.
Command or Action Purpose Step 5 interface tunnelnumber Example: Router(config)# interface tunnel1 Configures a tunnel interface and enters interface configuration mode. Step 6 tunnel destination ip-address Example: Router(config-if)# tunnel destination 172.
Interfaces: POS2/0 (ldp): xmit/recv LDP Id: 172.31.255.255:0 Tunnel1 (ldp): Targeted -> 192.168.255.255 Targeted Hellos: 172.16.0.0 -> 192.168.255.255 (ldp): active, xmit/recv LDP Id: 192.168.255.255:0 172.16.0.0 -> 192.168.0.0 (tdp): passive, xmit/recv TDP Id: 192.
ip unnumbered Loopback0 mpls ip mpls label protocol ldp Specifying the LDP Router ID The mpls ldp router-id command allows you to establish the IP address of an interface as the LDP router ID. The following steps describe the normal process for determining the LDP router ID: 1 The router considers all the IP addresses of all operational interfaces.
SUMMARY STEPS 1. enable 2. configure terminal 3. mpls ip 4. mpls label protocol { ldp | tdp | both } 5. mpls ldp router-id interface [ force ] 6. exit 7. show mpls ldp discovery [ all | detail | vrf vpn-name ] DETAILED STEPS Command or Action Purpose Step 1 enable Example: Router> enable Enables privileged EXEC mode.
Command or Action Purpose Step 6 exit Example: Router(config)# exit Exits global configuration mode and enters privileged EXEC mode. Step 7 show mpls ldp discovery [ all | detail | vrf vpn- name ] Example: Router# show mpls ldp discovery Displays the LDP identifier for the local router.
SUMMARY STEPS 1. enable 2. configure terminal 3. mpls ip 4. mpls label protocol { ldp | tdp | both } 5. interface type number 6. mpls ip 7. exit 8. mpls ldp explicit-null [ for prefix-acl | to peer-acl | for prefix-acl to peer-acl ] 9.
Command or Action Purpose Step 5 interface type number Example: Router(config)# interface atm2/0 Specifies the interface to be configured and enters interface configuration mode. Step 6 mpls ip Example: Router(config-if)# mpls ip Configures MPLS hop-by-hop forwarding on the interface.
Examples Enabling explicit-null on an egress LSR causes that LSR to advertise the explicit-null label to all adjacent MPLS routers. Router# configure terminal Router(config)# mpls ldp explicit-null If.
Router# configure terminal Router(config)# mpls label protocol ldp Router(config)# access-list 15 permit host 10.15.15.15 Router(config)# mpls ldp explicit-null to 15 If you issue the show mpls forwarding-table command, the output shows that explicit null labels are going only to the router specified in the access list.
If a router has a password configured for a neighbor, but the neighboring router does not have a password configured, a message such as the following appears on the console who has a password configured while the two routers attempt to establish an LDP session.
Command or Action Purpose Step 5 mpls ldp neighbor [ vrf vpn-name ] ip- address [ password [ 0-7 ] password-string ] Example: Router(config)# mpls ldp neighbor 172.27.0.15 password onethirty9 Specifies authentication between two LDP peers. Step 6 exit Example: Router(config)# exit Exits global configuration mode and enters privileged EXEC mode.
Peer LDP Ident: 10.0.0.21:0; Local LDP Ident 10.0.0.22:0 TCP connection: 10.0.0.21.646 - 10.0.0.22.14709; MD5 on State: Oper; Msgs sent/rcvd: 1020/1019; Downstream; Last TIB rev sent 2034 Up time: 00:00:39; UID: 3; Peer Id 1; LDP discovery sources: FastEthernet1/1; Src IP addr: 172.
Note The configuration examples below show only the commands related to configuring LDP for Router 1, Router 2, and Router 3 in the sample network shown in the figure above. Router 1 Configuration ip cef distributed !Assumes R1 supports distributed CEF interface Loopback0 !Loopback interface for LDP ID.
!Use LDP (configured i/f default) interface POS3/0/1 ip address 192.168.0.44 255.0.0.0 mpls ip !Enable hop-by-hop MPLS forwarding mpls label protocol tdp !Use TDP for this interface The configuration of Router 2 also uses the mpls label protocol ldp command in interface configuration mode.
global configuration mode makes it unnecessary to explicitly specify LDP as part of the configuration from the Tunnel14 and Tunnel16. ip cef distributed !Router1 supports distributed CEF mpls label protocol ldp !Use LDP as default for all interfaces interface Loopback0 !Loopback interface for LDP ID.
Additional References Related Documents Related Topic Document Title Configures LDP on every interface associated with a specified IGP instance. MPLS LDP Autoconfiguration Ensures that LDP is fully established before the IGP path is used for switching.
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Table 2 Feature Information for MPLS Label Distribution Protocol Overview Feature Name Releases Feature Information MPLS Label Distribution Protocol 12.0(10)ST 12.0(14)ST 12.1(2)T 12.1(8a)E 12.2(2)T 12.2(4)T 12.2(8)T 12.0(21)ST 12.0(22)S 12.0(23)S 12.
Feature Name Releases Feature Information In Cisco IOS Release 12.2(4)T, support was added for Cisco MGX 8850 and MGX 8950 switches equipped with a Cisco MGX RPM-PR card, and the VPI range in the show mpls atm-ldp bindings and show mpls ip binding commands was changed to 4095.
Feature Name Releases Feature Information rather than the tag-switching form. Previously, commands were saved by using the tag- switching form of the command, for backward compatibility. See the Saving Configurations MPLS Tag Switching Commands, page 11 for more information.
Establishing Nondirectly Connected MPLS LDP Sessions Example MPLS LDP Configuration Guide, Cisco IOS Release 12.4 30.
MPLS LDP Session Protectio n The MPLS LDP Session Protection feature provides faster label distribution protocol convergence when a link recovers following an outage.
• If the LSR is one hop from its neighbor, it is directly connected to its neighbor. The LSR sends out LDP Hello messages as User Datagram Protocol (UDP) packets to all the routers on the subnet. The hello message is called an LDP Link Hello. A neighboring LSR responds to the hello message and the two routers begin to establish an LDP session.
How to Configure MPLS LD P Session Protection • Enabling MPLS LDP Session Protection, page 33 • Verifying MPLS LDP Session Protection, page 35 • Troubleshooting Tips, page 36 Enabling MPLS LDP Session Protection You use the mpls ldp session protection command to enable MPLS LDP Session Protection.
Command or Action Purpose Step 2 configure terminal Example: Router# configure terminal Enters global configuration mode. Step 3 ip cef [ distributed ] Example: Router(config)# ip cef Configures Cisco Express Forwarding.
Command or Action Purpose Step 9 exit Example: Router(config-if)# exit Exits from interface configuration mode. Step 10 mpls ldp session protection [ vrf vpn-name ] [ for acl ] [ duration seconds ] Example: Router(config)# mpls ldp session protection Enables MPLS LDP Session Protection.
Up time: 21:09:56 LDP discovery sources: Targeted Hello 10.0.0.5 -> 10.0.0.3, active Addresses bound to peer LDP Ident: 10.3.104.3 10.0.0.2 10.0.0.3 Step 3 show mpls ldp neighbor detail Issue this command to check that the MPLS LDP Session Protection state is Ready or Protecting.
mode hsa ! ip cef distributed no ip domain-lookup multilink bundle-name both mpls label protocol ldp mpls ldp session protection no mpls traffic-eng auto-bw timers frequency 0 tag-switching tdp router-id Loopback0 force ! interface Loopback0 ip address 10.
! ip subnet-zero ip cef distributed mpls label protocol ldp mpls ldp session protection no mpls traffic-eng auto-bw timers frequency 0 tag-switching tdp router-id Loopback0 force ! interface Loopback0 ip address 10.
interface Ethernet1/4 ip address 10.0.0.2 255.0.0.0 no ip directed-broadcast full-duplex mpls label protocol ldp tag-switching ip ! router ospf 100 log-adjacency-changes redistribute connected network 10.0.0.5 0.0.0.0 area 100 network 10.0.0.0 0.255.255.
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MPLS LDP Inbound Label Bin ding Filtering Multiprotocol Label Switching (MPLS) Label Distribution Protocol (LDP) supports inbound label binding filtering.
How to Configure MPLS LD P Inbound Label Binding Fil tering • Configuring MPLS LDP Inbound Label Binding Filtering, page 42 • Verifying that MPLS LDP Inbound Label Bindings are Filtered, page 44 Configuring MPLS LDP Inbound Label Binding Filtering Perform this task to configure a router for inbound label filtering.
Command or Action Purpose Step 3 ip access-list standard access-list-number Example: Example: Router(config)# ip access-list standard 1 Defines a standard IP access list with a number. Step 4 permit { source [ source-wildcard ] | any } [ log ] Example: Example: Router(config-std-nacl)# permit 10.
Verifying that MPLS LDP Inbound Labe l Bindings are Filtered If inbound filtering is enabled, perform the following steps to verify that inbound label bindings are filtered: SUMMARY STEPS 1. Enter the show mpls ldp neighbor command to show the status of the LDP session, including the name or number of the ACL configured for inbound filtering.
access-list-number | access-list-name ] Note It is important that you enter this command to see how the access list is defined; otherwise, you cannot verify inbound label binding filtering. The following command output shows the contents of IP access list 1: Example: Router# show ip access 1 Standard IP access list 1 permit 10.
In the following example, the show mpls ldp bindings neighbor command displays label bindings that were learned from 10.110.0.10. This example verifies that the LIB does not contain label bindings for prefixes that have been excluded. Router# show mpls ldp bindings neighbor 10.
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Table 3 Feature Information for MPLS LDP Inbound Label Binding Filtering Feature Feature Name Releases Feature Information MPLS LDP Inbound Label Binding Filtering Feature 12.
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Verifying that MPLS LDP Inbound Label Bindings are Filtered MPLS LDP Configuration Guide, Cisco IOS Release 12.4 50.
MPLS LDP Autoconfiguration The MPLS LDP Autoconfiguration feature enables you to globally configure Label Distribution Protocol (LDP) on every interface associated with a specified Interior Gateway Protocol (IGP) instance.
Information About MPLS L DP Autoconfiguration To enable LDP, you should configure it globally and on each interface where it is needed. Configuring LDP on many interfaces can be time-consuming.
DETAILED STEPS Command or Action Purpose Step 1 enable Example: Router> enable Enables privileged EXEC mode. • Enter your password if prompted. Step 2 configure terminal Example: Router# configure terminal Enters global configuration mode. Step 3 mpls ip Example: Router(config)# mpls ip Globally enables hop-by-hop forwarding.
Command or Action Purpose Step 8 router ospf process-id Example: Router(config)# router ospf 1 Enables OSPF routing and enters router configuration mode. Step 9 network ip-address wildcard-mask area area-id Example: Router(config-router)# network 10.0.
DETAILED STEPS Command or Action Purpose Step 1 enable Example: Router> enable Enables privileged EXEC mode. • Enter your password if prompted. Step 2 configure terminal Example: Router# configure terminal Enters global configuration mode.
Enables privileged EXEC mode. Enter your password if prompted. Step 2 show mpls interfaces [ type number | vrf vpn-name ][ all ] [ detail ] [ internal ] The show mpls interfaces command displays the m.
Serial2/0 (ldp): xmit/recv Enabled: Interface config, IGP config; Hello interval: 5000 ms; Transport IP addr: 10.11.11.11 LDP Id: 10.10.10.10:0 Src IP addr: 10.
Command or Action Purpose Step 3 interface type number Example: Router(config)# interface POS 0/2 Specifies the interface to configure and enters interface configuration mode. Step 4 ip address prefix mask Example: Router(config-if)# ip address 10.50.
Command or Action Purpose Step 10 mpls ldp autoconfig [level-1 | level-2] Example: Router(config-router)# mpls ldp autoconfig Enables the LDP for interfaces that belong to an IS-IS process. Step 11 end Example: Router(config-router)# end Exits router configuration mode and returns to privileged EXEC mode.
Command or Action Purpose Step 3 interface type number Example: Router(config)# interface POS 3/0 Specifies the interface to configure and enters interface configuration mode. Step 4 no mpls ldp igp autoconfig Example: Router(config-if)# no mpls ldp igp autoconfig Disables LDP for that interface.
• IS-IS is up. • LDP is enabled. If the MPLS LDP Autoconfiguration feature is not enabled on an interface, the output looks like the following: Example: Interface: Ethernet0; ISIS tag null enabled.
mpls ldp autoconfig area 3 end interface POS 1/0 no mpls ldp igp autoconfig MPLS LDP Autoconfiguration with IS- IS Examples The following example shows the configuration of the MPLS LDP Autoconfiguration feature on POS0/2 and 0/3 interfaces, which are running IS-IS processes: configure terminal interface POS 0/2 ip address 10.
MIBs MIB MIBs Link MPLS LDP MIB To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL: http://www.
Table 4 Feature Information for MPLS LDP Autoconfiguration Feature Name Releases Feature Information MPLS LDP Autoconfiguration 12.0(30)S 12.0(32)SY 12.2(28)SB 12.2(33)SRB 12.3(14)T 15.0(1)M 12.2(33)XNE This feature enables you to globally configure LDP on every interface associated with a specified Interior Gateway Protocol (IGP) instance.
MPLS LDP Graceful Restart When a router is configured with Multiprotocol Label Switching (MPLS) Label Distribution Protocol (LDP) Graceful Restart (GR), it assists a neighboring router that has MPLS LDP Stateful Switchover/ Nonstop Forwarding (SSO/NSF) Support and Graceful Restart to recover gracefully from an interruption in service.
• MPLS LDP GR is supported in strict helper mode. • Tag Distribution Protocol (TDP) sessions are not supported. Only LDP sessions are supported. • MPLS LDP GR cannot be configured on label-controlled ATM (LC-ATM) interfaces. • MPLS LDP SSO/NSF is supported in IOS Release 12.
• mpls ldp graceful-restart timers neighbor-liveness • mpls ldp graceful-restart timers max-recovery How a Route Processor Advertises Tha t It Supports MPLS LDP Graceful Restart A route processor that is configured to perform MPLS LDP GR includes the Fault Tolerant (FT) Type Length Value (TLV) in the LDP initialization message.
SUMMARY STEPS 1. enable 2. configure terminal 3. ip cef [ distributed ] 4. mpls ldp graceful-restart 5. interface type slot/port 6. mpls ip 7. mpls label protocol { ldp | tdp | both } DETAILED STEPS Command or Action Purpose Step 1 enable Example: Router> enable Enables privileged EXEC mode.
Command or Action Purpose Step 6 mpls ip Example: Router(config-if)# mpls ip Configures MPLS hop-by-hop forwarding for an interface. Step 7 mpls label protocol { ldp | tdp | both } Example: Router(config-if)# mpls label protocol ldp Configures the use of LDP for an interface.
Router 1 configured with LDP GR: boot system slot0:rsp-pv-mz hw-module slot 2 image slot0:rsp-pv-mz hw-module slot 3 image slot0:rsp-pv-mz ! ip subnet-zero ip cef mpls label range 16 10000 static 1000.
mpls ldp logging neighbor-changes mpls ldp graceful-restart mpls traffic-eng tunnels no mpls traffic-eng auto-bw timers frequency 0 no mpls advertise-labels mpls ldp router-id Loopback0 force ! interface Loopback0 ip address 17.
no mpls traffic-eng auto-bw timers frequency 0 mpls ldp discovery directed-hello interval 12 mpls ldp discovery directed-hello holdtime 130 mpls ldp discovery directed-hello accept mpls ldp router-id Loopback0 force ! interface Loopback0 ip address 19.
RFCs RFCs 2 Title RFC 3036 LDP Specification RFC 3478 Graceful Restart Mechanism for Label Distribution Technical Assistance Description Link The Cisco Technical Support & Documentation website contains thousands of pages of searchable technical content, including links to products, technologies, solutions, technical tips, and tools.
Table 5 Feature Information for MPLS LDP Graceful Restart Feature Name Releases Feature Information MPLS LDP Graceful Restart 12.0(29)S 12.3(14)T 12.2(33)SRA MPLS LDP Graceful Restart assists a neighb.
Un point important après l'achat de l'appareil (ou même avant l'achat) est de lire le manuel d'utilisation. Nous devons le faire pour quelques raisons simples:
Si vous n'avez pas encore acheté Cisco Systems 12.4 c'est un bon moment pour vous familiariser avec les données de base sur le produit. Consulter d'abord les pages initiales du manuel d'utilisation, que vous trouverez ci-dessus. Vous devriez y trouver les données techniques les plus importants du Cisco Systems 12.4 - de cette manière, vous pouvez vérifier si l'équipement répond à vos besoins. Explorant les pages suivantes du manuel d'utilisation Cisco Systems 12.4, vous apprendrez toutes les caractéristiques du produit et des informations sur son fonctionnement. Les informations sur le Cisco Systems 12.4 va certainement vous aider à prendre une décision concernant l'achat.
Dans une situation où vous avez déjà le Cisco Systems 12.4, mais vous avez pas encore lu le manuel d'utilisation, vous devez le faire pour les raisons décrites ci-dessus,. Vous saurez alors si vous avez correctement utilisé les fonctions disponibles, et si vous avez commis des erreurs qui peuvent réduire la durée de vie du Cisco Systems 12.4.
Cependant, l'un des rôles les plus importants pour l'utilisateur joués par les manuels d'utilisateur est d'aider à résoudre les problèmes concernant le Cisco Systems 12.4. Presque toujours, vous y trouverez Troubleshooting, soit les pannes et les défaillances les plus fréquentes de l'apparei Cisco Systems 12.4 ainsi que les instructions sur la façon de les résoudre. Même si vous ne parvenez pas à résoudre le problème, le manuel d‘utilisation va vous montrer le chemin d'une nouvelle procédure – le contact avec le centre de service à la clientèle ou le service le plus proche.
