-
Cisco IOS XR MPLS Command Reference, Release 3.7
-
Preface
-
MPLS Label Distribution Protocol Commands on Cisco IOS XR Software
-
MPLS Forwarding Commands on Cisco IOS XR Software
-
MPLS Traffic Engineering Commands on Cisco IOS XR Software
-
RSVP Infrastructure Commands on Cisco IOS XR Software
-
MPLS Optical User Network Interface Commands on Cisco IOS XR Software
-
MPLS OAM Commands on Cisco IOS XR Software
-
Virtual Private Network Commands on Cisco IOS XR Software
-
Virtual Private LAN Services Commands on Cisco IOS XR Software
-
Index
-
Table Of Contents
MPLS Label Distribution Protocol Commands on Cisco IOS XR Software
clear mpls ldp msg-counters neighbor
discovery instance-tlv disable
show mpls ldp graceful-restart
show mpls ldp statistics msg-counters
MPLS Label Distribution Protocol Commands on Cisco IOS XR Software
This chapter describes the commands used to configure Label Distribution Protocol (LDP) in a Multiprotocol Label Switching (MPLS) network.
LDP provides a standard methodology for hop-by-hop (or dynamic label) distribution in an MPLS network by assigning labels to routes that have been chosen by the underlying Interior Gateway Protocol (IGP) routing protocols. The resulting labeled paths, called label switch paths (LSPs), forward labeled traffic across an MPLS backbone.
LDP also provides the means for label switching routers (LSRs) to request, distribute, and release label prefix binding information to peer routers in a network. LDP enables LSRs to discover potential peers and establish LDP sessions with those peers to exchange label binding information.
For detailed information about MPLS concepts, configuration tasks, and examples, refer to the
Cisco IOS XR MPLS Configuration Guide.backoff
To configure the parameters for the LDP backoff mechanism, use the backoff command in MPLS LDP configuration mode. To return to the default behavior, use the no form of this command.
backoff initial maximum
no backoff
Syntax Description
initial
Initial backoff delay in seconds. Range is 5 to 2147483 seconds.
maximum
Maximum backoff delay in seconds. Range is 5 to 2147483 seconds.
Defaults
initial: 15 seconds
maximum: 120 seconds
Command Modes
MPLS LDP configuration
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes the proper task IDs. For detailed information about user groups and task IDs, see the Configuring AAA Services on Cisco IOS XR Software module of the Cisco IOS XR System Security Configuration Guide.
The LDP backoff mechanism prevents two incompatibly-configured label switch routers from engaging in an unthrottled sequence of session setup failures. If a session setup attempt fails (due to incompatibility), each LSR delays the next attempt increasing the delay exponentially with each successive failure (until the maximum backoff delay is reached).
Task ID
Examples
The following example shows how to configure the initial backoff delay to 30 seconds and the maximum backoff delay to 240 seconds:
RP/0/RP0/CPU0:router# configRP/0/RP0/CPU0:router(config)# mpls ldpRP/0/RP0/CPU0:router(config-ldp)# backoff 30 240Related Commands
Displays information about the configured session setup backoff parameters and LDP peers.
Displays current LDP parameter settings.
clear mpls ldp msg-counters neighbor
To clear the LDP message counters, use the clear mpls ldp msg-counters command in EXEC mode.
clear mpls ldp msg-counters neighbor {A.B.C.D. | all}
Syntax Description
Command Modes
EXEC
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes the proper task IDs. For detailed information about user groups and task IDs, see the Configuring AAA Services on Cisco IOS XR Software module of the Cisco IOS XR System Security Configuration Guide.
Use the clear mpls ldp msg-counters neighbor command to clear the statistics on message counters for a specific neighbor (IP address) or for all neighbors. These message counters count the number of LDP protocol messages sent to and received from LDP neighbors.
Task ID
Examples
The following example shows how to clear message counters for neighbor 10.20.20.20:
RP/0/RP0/CPU0:router# clear mpls ldp msg-counters neighbor 10.20.20.20Related Commands
Displays statistics about the type and count of the messages sent and received from neighbors.
clear mpls ldp neighbor
To force LDP session restart, use the clear mpls ldp neighbor command in EXEC mode.
clear mpls ldp neighbor [A.B.C.D.]
Syntax Description
Defaults
No default behavior or values
Command Modes
EXEC
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes the proper task IDs. For detailed information about user groups and task IDs, see the Configuring AAA Services on Cisco IOS XR Software module of the Cisco IOS XR System Security Configuration Guide.
Use the clear mpls ldp neighbor command to restart a single LDP session or all LDP sessions (without restarting the LDP process itself).
Task ID
Examples
The following example shows how to force an unconditional LDP session restart:
RP/0/RP0/CPU0:router# clear mpls ldp neighbor 10.20.20.20Related Commands
default-route
To enable MPLS switching for IP default route by allocating and advertising non-null label, use the default-route command in MPLS LDP configuration mode. To return to the default behavior, use the no form of this command.
default-route
no default-route
Syntax Description
This command has no arguments or keywords.
Defaults
Allocates null (implicit or explicit) local label for IP default route prefix 0.0.0.0/0.
Command Modes
MPLS LDP configuration
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes the proper task IDs. For detailed information about user groups and task IDs, see the Configuring AAA Services on Cisco IOS XR Software module of the Cisco IOS XR System Security Configuration Guide.
When the IP default route 0.0.0.0/0 is configured on an egress router, it is advertised through IGP to other routers to enable default IP forwarding. When MPLS LDP is configured and establishing LSPs for other prefixes, you can emulate default forwarding and switching for MPLS in the same way as IP forwarding. To do so, allocate a non-null local label and advertise this label to its peers.
Task ID
Examples
The following example shows how to enable default MPLS switching for default prefix:
RP/0/RP0/CPU0:router(config-ldp)# default-routeRelated Commands
discovery hello
To configure the interval between transmission of consecutive LDP discovery hello messages and the holdtime for a discovered LDP neighbor, use the discovery hello command in MPLS LDP configuration mode. To return to the default behavior, use the no form of this command.
discovery hello {holdtime seconds | interval seconds}
no discovery hello {holdtime | interval}
Syntax Description
Defaults
holdtime: 15 seconds
interval: 5 seconds
Command Modes
MPLS LDP configuration
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes the proper task IDs. For detailed information about user groups and task IDs, see the Configuring AAA Services on Cisco IOS XR Software module of the Cisco IOS XR System Security Configuration Guide.
Task ID
Examples
The following example shows how to configure the link hello holdtime to 30 seconds:
RP/0/RP0/CPU0:router(config-ldp)# discovery hello holdtime 30The following example shows how to configure the link hello interval to 10 seconds:
RP/0/RP0/CPU0:router(config-ldp)# discovery hello interval 10Related Commands
discovery instance-tlv disable
To disable transmit and receive processing for TLV, use the discovery instance-tlv disable command in MPLS LDP configuration mode. To return to the default behavior, use the no form of this command.
discovery instance-tlv disable
no discovery instance-tlv disable
Syntax Description
This command has no arguments or keywords.
Defaults
No default behavior or values
Command Modes
MPLS LDP configuration
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes the proper task IDs. For detailed information about user groups and task IDs, see the Configuring AAA Services on Cisco IOS XR Software module of the Cisco IOS XR System Security Configuration Guide.
Task ID
Examples
The following example shows how to disable transmit and receive processing for TLV:
RP/0/RP0/CPU0:router# configureRP/0/RP0/CPU0:router(config)# mpls ldpRP/0/RP0/CPU0:router(config-ldp)# discovery hello holdtime 30Related Commands
discovery targeted-hello
To configure the interval between transmission of consecutive LDP discovery targeted-hello messages, the hold time for a discovered targeted LDP neighbor, and to accept targeted hello from peers, use the discovery targeted-hello command in MPLS LDP configuration mode. To return to the default behavior, use the no form of this command.
discovery targeted-hello {accept [from acl] | holdtime seconds | interval seconds}
no discovery targeted-hello {accept | holdtime | interval}
Syntax Description
Defaults
accept: Targeted hello messages are not accepted from any source (neighbor).
holdtime: 90 seconds
interval: 10 seconds
Command Modes
MPLS LDP configuration
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes the proper task IDs. For detailed information about user groups and task IDs, see the Configuring AAA Services on Cisco IOS XR Software module of the Cisco IOS XR System Security Configuration Guide.
LDP supports IPv4 standard access lists only.
Task ID
Examples
The following example shows how to configure the targeted-hello holdtime to 45 seconds:
RP/0/RP0/CPU0:router(config-ldp)# discovery targeted-hello holdtime 45The following example shows how to configure the targeted-hello interval to 5 seconds:
RP/0/RP0/CPU0:router(config-ldp)# discovery targeted-hello interval 5The following example shows how to configure acceptance of targeted hellos from all peers:
RP/0/RP0/CPU0:router(config-ldp)# discovery targeted-hello acceptThe following example shows how to configure acceptance of targeted hello from peers 10.1.1.1 and 10.2.2.2 only:
RP/0/RP0/CPU0:router(config)# ipv4 access-list peer_acl_10RP/0/RP0/CPU0:router(config-ipv4-acl)# permit 10.1.1.1RP/0/RP0/CPU0:router(config-ipv4-acl)# permit 10.2.2.2RP/0/RP0/CPU0:router(config-ldp)# discovery targeted-hello accept from peer_acl_10Related Commands
discovery transport-address
To provide an alternative address for a Transmission Control Protocol (TCP) connection, use the discovery transport-address command in MPLS LDP interface configuration mode. To return to the default behavior, use the no form of this command.
discovery transport-address {A.B.C.D. | interface}
no discovery transport-address {A.B.C.D. | interface}
Syntax Description
A.B.C.D.
IP address to be advertised as the transport address in discovery hello messages.
interface
Advertises the IP address of the interface as the transport address in discovery hello messages.
Defaults
LDP advertises its LDP router ID as the transport address in LDP discovery hello messages.
Command Modes
MPLS LDP interface configuration
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes the proper task IDs. For detailed information about user groups and task IDs, see the Configuring AAA Services on Cisco IOS XR Software module of the Cisco IOS XR System Security Configuration Guide.
Establishing an LDP session between two routers requires a session TCP connection. To establish the session TCP connection each router must know the transport address (IP address) of the other router.
The LDP discovery mechanism provides the means for a router to advertise transport addresses. Transport address is implicit or explicit. Implicit addresses do not appear as part of the contents of the discovery hello messages sent to the peer. If explicit, the advertisement appears as part of the contents of discovery hello messages sent to the peer.
The discovery transport-address command modifies the default behavior described above. Using the interface keyword, LDP advertises the IP address of the interface in LDP discovery hello messages sent from the interface. Using the ip-address argument value, LDP advertises the IP address in LDP discovery hello messages sent from the interface.
Note
When a router has multiple links connecting it to its peer device, the router must advertise the same transport address in the LDP discovery hello messages it sends on all such interfaces.
Task ID
Examples
The following example shows how to specify an exiting address (10.10.3.1) as the transport address on POS interface 0/1/0/0:
RP/0/RP0/CPU0:router(config-ldp)# interface POS 0/1/0/0RP/0/RP0/CPU0:router(config-ldp-if)# discovery transport-address 10.10.3.1RP/0/RP0/CPU0:router# show mpls ldp neighborPeer LDP Identifier: 10.44.44.44:0TCP connection: 10.44.44.44:65520 - 10.10.3.1:646Graceful Restart: Yes (Reconnect Timeout: 15 sec, Recovery: 180 sec)State: Oper; Msgs sent/rcvd: 13/9Up time: 00:00:11LDP Discovery Sources:POS 0/1/0/0Addresses bound to this peer:10.10.3.2 10.44.44.44Related Commands
Displays the status of the LDP discovery process.
Displays information about LDP neighbors.
explicit-null
To configure a router to advertise explicit null labels instead of implicit null labels, use the explicit-null command in MPLS LDP configuration mode. To return to the default behavior, use the no form of this command.
explicit-null {to peer-acl | for prefix-acl [to peer-acl]}
no explicit-null
Syntax Description
Defaults
Implicit null is advertised as default null label for routes such as directly connected routes.
Command Modes
MPLS LDP configuration
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes the proper task IDs. For detailed information about user groups and task IDs, see the Configuring AAA Services on Cisco IOS XR Software module of the Cisco IOS XR System Security Configuration Guide.
Normally, LDP advertises an implicit null label for directly-connected routes. The implicit null label causes the previous hop router to perform next to last router hop popping.
Run the explicit-null command to advertise explicit-null labels in place of implicit null labels for directly connected prefixes. Use mpls ldp explicit-null command when running in global configuration mode.
LDP supports IPv4 standard access lists only.
Task ID
Examples
The following command shows how to advertise explicit null for all directly connected routes to all LDP peers:
RP/0/RP0/CPU0:router(config-ldp)# explicit-nullThe following command sequence shows how to advertise explicit-null for directly connected route192.168.0.0 to all LDP peers and implicit-null for all other directly connected routes:
RP/0/RP0/CPU0:router(config)# ipv4 access-list pfx_acl_192_168RP/0/RP0/CPU0:router(config-ipv4-acl)# permit 192.168.0.0RP/0/RP0/CPU0:router(config-ldp)# explicit-null for pfx_acl_192_168The following command sequence shows how to send explicit-null for all directly connected routes to peers 10.1.1.1 and 10.2.2.2 and implicit-null to all other peers:
RP/0/RP0/CPU0:router(config)# ipv4 access-list peer_acl_10RP/0/RP0/CPU0:router(config-ipv4-acl)# permit 10.1.1.1RP/0/RP0/CPU0:router(config-ipv4-acl)# permit 10.2.2.2RP/0/RP0/CPU0:router(config-ldp)# explicit-null to peer_acl_10The following command shows how to advertise explicit-null for prefix 192.168.0.0 to peers 10.1.1.1 and 10.2.2.2 and advertise implicit-null for all other applicable routes to all other peers:
RP/0/RP0/CPU0:router(config-ldp)# explicit-null for pfx_acl_192_168 to peer_acl_10Related Commands
Displays the contents of LDP label information base (LIB).
Displays the contents of the LDP forwarding database.
Displays current LDP parameter settings.
graceful-restart (MPLS LDP)
To configure graceful restart, use the graceful-restart command in MPLS LDP configuration mode. To return to the default behavior, use the no form of this command.
graceful-restart [reconnect-timeout seconds | forwarding-state-holdtime seconds]
no graceful-restart [reconnect-timeout | forwarding-state-holdtime]
Syntax Description
Defaults
By default, graceful restart is disabled.
reconnect-timeout: 120 seconds
forwarding-state-holdtime: 180 seconds
Command Modes
MPLS LDP configuration
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes the proper task IDs. For detailed information about user groups and task IDs, see the Configuring AAA Services on Cisco IOS XR Software module of the Cisco IOS XR System Security Configuration Guide.
Use the LDP graceful restart capability to achieve nonstop forwarding (NSF) during an LDP control plane communication failure or restart. To configure graceful restart between two peers, enable LDP graceful restart on both label switching routers (LSRs).
When an LDP graceful restart session is established and there is control plane failure, the peer LSR starts graceful restart procedures, initially keeps the forwarding state information pertaining to the restarting peer, and marks this state as stale. If the restarting peer does not reconnect within the reconnect timeout, the stale forwarding state is removed. If the restarting peer reconnects within the reconnect time period, it is provided recovery time to resynchronize with its peer. After this time, any unsynchronized state is removed.
The value of the forwarding state hold time keeps the forwarding plane state associated with the LDP control-plane in case of a control-plane restart or failure. If the control plane fails, the forwarding plane retains the LDP forwarding state for twice the forwarding state hold time. The value of the forwarding state hold time is also used to start the local LDP forwarding state hold timer after the LDP control plane restarts. When the LDP graceful restart sessions are renegotiated with its peers, the restarting LSR sends the remaining value of this timer as the recovery time to its peers. Upon local LDP restart with graceful restart enabled, LDP does not replay forwarding updates to MPLS forwarding until the forwarding state hold timer expires.
Note
Task ID
Examples
The following example shows how to configure an existing session for graceful restart:
RP/0/RP0/CPU0:router(config-ldp)# graceful-restartThe following example shows how to configure an existing session for graceful restart:
RP/0/RP0/CPU0:router(config-ldp)# graceful-restartRP/0/RP0/CPU0:Apr 3 10:56:05.392 : mpls_ldp[336]: %ROUTING-LDP-5-NBR_CHANGE : Nbr 2.2.2.2:0, DOWNRP/0/RP0/CPU0:Apr 3 10:56:05.392 : mpls_ldp[336]: %ROUTING-LDP-5-NBR_CHANGE : Nbr 3.3.3.3:0, DOWNRP/0/RP0/CPU0:Apr 3 10:56:09.525 : mpls_ldp[336]: %ROUTING-LDP-5-NBR_CHANGE : Nbr 3.3.3.3:0, UPRP/0/RP0/CPU0:Apr 3 10:56:11.114 : mpls_ldp[336]: %ROUTING-LDP-5-NBR_CHANGE : Nbr 2.2.2.2:0, UPRP/0/RP0/CPU0:router# show mpls ldp neighbor briefvPeer GR Up Time Discovery Address----------------- -- --------------- --------- -------3.3.3.3:0 Y 00:01:04 3 82.2.2.2:0 N 00:01:02 2 5RP/0/RP0/CPU0:router# show mpls ldp graceful-restartForwarding State Hold timer : Not RunningGR Neighbors : 1Neighbor ID Up Connect Count Liveness Timer Recovery Timer--------------- -- ------------- ------------------ ------------------3.3.3.3 Y 1 - -Related Commands
holdtime (MPLS LDP)
To change the time for which an LDP session is maintained in the absence of LDP messages from the session peer, use the holdtime command in MPLS LDP configuration mode. To return to the default behavior, use the no form of this command.
holdtime seconds
no holdtime
Syntax Description
seconds
Time that an LDP session is maintained in the absence of LDP messages from the session peer. Range is 15 to 65535 seconds.
Defaults
seconds: 180
Command Modes
MPLS LDP configuration
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes the proper task IDs. For detailed information about user groups and task IDs, see the Configuring AAA Services on Cisco IOS XR Software module of the Cisco IOS XR System Security Configuration Guide.
Task ID
Examples
The following example shows how to change the hold time of LDP sessions to 30 seconds:
RP/0/RP0/CPU0:router(config-ldp)# holdtime 30Related Commands
igp auto-config disable
To disable LDP auto-configuration, use the igp auto-config disable command in MPLS LDP interface configuration mode. To return to the default behavior, use the no form of this command.
igp auto-config disable
Syntax Description
This command has no arguments or keywords.
Defaults
No default behavior or values
Command Modes
MPLS LDP interface configuration
Command History
Release 3.5.0
This command was introduced on the Cisco CRS-1 and Cisco XR 12000 Series Router.
Release 3.6.0
No modification.
Release 3.7.0
No modification.
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes the proper task IDs. For detailed information about user groups and task IDs, see the Configuring AAA Services on Cisco IOS XR Software module of the Cisco IOS XR System Security Configuration Guide.
IGP auto-configuration can be enabled on ISIS and OSPF. Configuration details are described in
Cisco IOS XR Routing Configuration Guide, Release 3.5.Task ID
Examples
The following example shows how to disable LDP auto-configuration on POS 0/1/0/3:
RP/0/RP0/CPU0:router(config)# mpls ldpRP/0/RP0/CPU0:router(config-ldp)# interface pos 0/1/0/3RP/0/RP0/CPU0:router(config-ldp-if)# igp auto-config disableRelated Commands
igp sync delay
To enable LDP IGP sync delay timer feature, use the igp sync delay command in MPLS LDP configuration mode. To return to the default behavior, use the no form of this command.
igp sync delay seconds
no igp sync delay
Syntax Description
seconds
Time that declaration of LDP sync state being up is delayed after session establishment upon link coming up. Range is 5 to 60 seconds.
Defaults
LDP does not delay declaration of sync up and notifies IGP as soon sync up conditions are met for a link.
Command Modes
MPLS LDP configuration
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes the proper task IDs. For detailed information about user groups and task IDs, see the Configuring AAA Services on Cisco IOS XR Software module of the Cisco IOS XR System Security Configuration Guide.
By default, LDP declares LDP sync up as soon as all the requisite conditions are met; namely:
•
•
•
This minimizes traffic loss on link up but can still lead to substantial traffic loss under certain circumstances (for example, when interoperating with an LSR with ordered mode operation). It may be necessary to delay declaration of sync up after the session comes up by configuring a timeout period.
Task ID
Examples
The following example shows how to configure LDP to delay declaration of sync-up to 30 seconds:
RP/0/RP0/CPU0:router# configureRP/0/RP0/CPU0:router(config)# mpls ldpRP/0/RP0/CPU0:router(config-ldp)# igp sync delay 30Related Commands
interface (MPLS LDP)
To configure or enable MPLS LDP on an interface, use the interface command in MPLS LDP configuration mode. To return to the default behavior, use the no form of this command.
interface type interface-id
no interface type interface-id
Syntax Description
Defaults
No default behavior or values
Command Modes
MPLS LDP configuration
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes the proper task IDs. For detailed information about user groups and task IDs, see the Configuring AAA Services on Cisco IOS XR Software module of the Cisco IOS XR System Security Configuration Guide.
