Feedback
Table Of Contents
mpls ldp graceful-restart timers forwarding-holding
mpls ldp graceful-restart timers max-recovery
mpls ldp graceful-restart timers neighbor-liveness
mpls ldp neighbor implicit-withdraw
mpls ldp neighbor labels accept
mpls traffic-eng administrative-weight
mpls traffic-eng attribute-flags
mpls traffic-eng auto-bw timers
mpls ldp explicit-null
To cause a router to advertise an Explicit Null label in situations where it would normally advertise an Implicit Null label, use the mpls ldp explicit-null command in global configuration mode. To disable this feature, use the no form of this command.
mpls ldp explicit-null [for prefix-acl | to peer-acl | for prefix-acl to peer-acl]
no mpls ldp explicit-null
Syntax Description
Defaults
Implicit Null is advertised for directly connected routes unless the command mpls ldp explicit-null has been executed.
Command Modes
Global configuration
Command History
Usage Guidelines
Normally, LDP advertises an Implicit Null label for directly connected routes. The Implicit Null label causes the previous hop (penultimate) router to do penultimate hop popping. Situations exist where it might be desirable to prevent the penultimate router from performing penultimate hop popping and to force it to replace the incoming label with the Explicit Null label.
When you issue the mpls ldp explicit-null command, Explicit Null is advertised in place of Implicit Null for directly connected prefixes permitted by the prefix-acl argument to peers permitted by the peer-acl argument.
If you do not specify the prefix-acl argument in the command, Explicit Null is advertised in place of Implicit Null for all directly connected prefixes.
If you do not specify the peer-acl argument in the command, Explicit Null is advertised in place of Implicit Null to all peers.
Examples
The following command shows how to cause Explicit Null to be advertised for all directly connected routes to all LDP peers:
Router(config)# mpls ldp explicit-nullThe following command sequence shows how to cause Explicit Null to be advertised for directly connected route 10.5.0.0 to all LDP peers and Implicit Null to be advertised for all other directly connected routes:
Router(config)# mpls ldp explicit-nullRouter(config)# ip access-list standard adv-exp-nullRouter(config-std-nacl)# permit 10.5.0.0Router(config-std-nacl)# deny anyRouter(config-std-nacl)#Related Commands
show mpls ip binding
Displays specified information about label bindings learned by LDP.
mpls ldp graceful-restart
To enable Multiprotocol Label Switching (MPLS) Label Distribution Protocol (LDP) Graceful Restart, use the mpls ldp graceful-restart command in global configuration mode. To disable LDP Graceful Restart, use the no form of this command.
mpls ldp graceful-restart
no mpls ldp graceful-restart
Syntax Description
This command has no arguments or keywords.
Defaults
LDP Graceful Restart is not enabled.
Command Modes
Global configuration
Command History
Usage Guidelines
LDP Graceful Restart must be enabled before an LDP session is established.
Using the no form of the command disables the Graceful Restart functionality on all LDP sessions.
Examples
The command in the following example enables LDP Graceful Restart on a router:
Router(config)# mpls ldp graceful-restartRelated Commands
mpls ldp graceful-restart timers forwarding-holding
To specify the amount of time the Multiprotocol Label Switching (MPLS) forwarding state should be preserved after the control plane restarts, use the mpls ldp graceful-restart timers forwarding-holding command in global configuration mode. To revert to the default timer value, use the no form of this command.
mpls ldp graceful-restart timers forwarding-holding secs
no mpls ldp graceful-restart timers forwarding-holding
Syntax Description
Defaults
After the control plane on the Cisco 7500 and Cisco 10000 series router restarts, the MPLS forwarding state is preserved for 300 seconds.
Command Modes
Global configuration
Command History
Usage Guidelines
Configuring the local forwarding-holding timer to a value less than the IOS FT Reconnect Timeout of 120 seconds may prevent a Label Distribution Protocol (LDP) session from being established. Configure the forwarding-holding timer to less than 120 seconds only if an LDP neighbor has an FT Reconnect Timeout value of less than 120 seconds.
If the timer expires, all entries that are marked stale are deleted.
Examples
In the following example, the MPLS forwarding state is preserved for 300 seconds after the control plane restarts:
Router(config)# mpls ldp graceful-restart timers forwarding-holding 300Related Commands
mpls ldp graceful-restart timers max-recovery
To specify the amount of time a router should hold stale label-Forwarding Equivalence Class (FEC) bindings after a Label Distribution Protocol (LDP) session has been reestablished, use the mpls ldp graceful-restart timers max-recovery command in global configuration mode. To revert to the default timer value, use the no form of this command.
mpls ldp graceful-restart timers max-recovery secs
no mpls ldp graceful-restart timers max-recovery
Syntax Description
Defaults
Stale label-FEC bindings are held for 120 seconds after an LDP session has been reestablished.
Command Modes
Global configuration
Command History
Usage Guidelines
After the timer expires, all stale label-FEC bindings learned from the associated LDP session are removed, which results in the removal of any forwarding table entries that are based on those bindings.
Examples
In the following example, the router should hold stale label-FEC bindings after an LDP session has been reestablished for 180 seconds:
Router(config)# mpls ldp graceful-restart timers max-recovery 180Related Commands
mpls ldp graceful-restart timers neighbor-liveness
To specify the upper bound on the amount of time a router should wait for a Label Distribution Protocol (LDP) session to be reestablished, use the mpls ldp graceful-restart timers neighbor-liveness command in global configuration mode. To revert to the default timer value, use the no form of this command.
mpls ldp graceful-restart timers neighbor-liveness secs
no mpls ldp graceful-restart timers neighbor-liveness
Syntax Description
secs
The amount of time (in seconds) that the router should wait for an LDP session to be reestablished. The default is 120 seconds. The range is 5 to 300 seconds.
Defaults
The default is a maximum of 120 seconds.
Command Modes
Global configuration
Command History
Usage Guidelines
The amount of time a router waits for an LDP session to be reestablished is the lesser of the following values:
•
The value of the peer's fault tolerant (FT) type length value (TLV) reconnect timeout
•
If the router cannot reestablish an LDP session with the neighbor in the time allotted, the router deletes the stale label-FEC bindings received from that neighbor.
Examples
The command in the following example sets the amount of time that the router should wait for an LDP session to be reestablished to 30 seconds:
Router(config)# mpls ldp graceful-restart timers neighbor-liveness 30Related Commands
mpls ldp holdtime
To change the time for which an Label Distribution Protocol (LDP) session is maintained in the absence of LDP messages from the session peer, use the mpls ldp holdtime command in global configuration mode. To disable this command, use the no form of the command.
mpls ldp holdtime seconds
no mpls ldp holdtime seconds
Syntax Description
seconds
Number from 15 to 2147483 that defines the time, in seconds, an LDP session is maintained in the absence of LDP messages from the session peer. The default is 180.
Defaults
The default value for the seconds argument is 180.
Command Modes
Global configuration
Command History
Usage Guidelines
When an LDP session is established between two LSRs, the hold time used for the session is the lower of the values configured on the two LSRs.
Examples
The following example shows how to configure the hold time of LDP sessions for 30 seconds:
Router# mpls ldp holdtime 30Related Commands
show mpls ldp parameters
Displays the current LDP parameter.
show mpls atm-ldp bindings
Displays specified entries from the ATM label binding database.
mpls ldp loop-detection
To enable the label distribution protocol (LDP) optional loop detection mechanism, use the mpls ldp loop-detection command in global configuration mode. To disable this feature, use the no form of this command.
mpls ldp loop-detection
no mpls ldp loop-detection
Syntax Description
This command has no optional keywords or arguments.
Defaults
LDP loop detection is disabled.
Command Modes
Global configuration
Command History
Usage Guidelines
The LDP loop detection mechanism is intended for use in networks of devices that do not use time-to-live mechanisms (for example, ATM switches) that cannot fairly allocate device resources among traffic flows.
The LDP loop detection mechanism is used with the Downstream on Demand method of label distribution, supplementing the Downstream on Demand hop count mechanism to detect looping LSPs that might occur during routing transitions.
Examples
The following command sets the LDP loop detection mechanism on:
Router(config)# mpls ldp loop-detectionRelated Commands
mpls ldp maxhops
Limits the number of hops permitted in an LSP established by the Downstream on Demand method of label distribution.
mpls ldp maxhops
To limit the number of hops permitted in a label switched path (LSP) established by the Downstream on Demand method of label distribution, use the mpls ldp maxhops command in global configuration mode. To disable this feature, use the no form of this command.
mpls ldp maxhops number
no mpls ldp maxhops
Syntax Description
Defaults
The default is 254 hops.
Command Modes
Global configuration
Command History
Usage Guidelines
When an ATM label switch router (LSR) initiates a request for a label binding, it sets the hop count value in the Label Request message to 1. Subsequent ATM-LSRs along the path to the edge of the ATM label switching region increment the hop count before forwarding the Label Request message to the next hop.
When an ATM LSR receives a Label Request message, it does not send a Label Mapping message in response, nor does it propagate the request to the destination next hop if the hop count value in the request equals or exceeds the maxhops value. Instead, the ATM LSR returns an error message that specifies that the maximum allowable hop count has been reached. This threshold is used to prevent forwarding loops in the setting up of label switch paths across an ATM region.
Examples
The following example sets the hop count limit to 10:
Router(config)# mpls ldp maxhops 10Related Commands
mpls ldp neighbor implicit-withdraw
To configure the advertisement of a new label for a Forwarding Equivalence Class (FEC) without the withdrawal of the previously advertised label, use the mpls ldp neighbor implicit-withdraw command in global configuration mode. To disable this option for the specified neighbor, use the no form of this command.
mpls ldp neighbor [vrf vpn-name] ip-addr implicit-withdraw
no mpls ldp neighbor [vrf vpn-name] ip-addr [implicit-withdraw]
Syntax Description
vrf vpn-name
(Optional) VPN routing and forwarding instance for the specified neighbor.
ip-addr
Router ID (IP address) that identifies a neighbor.
Defaults
When the vrf keyword is not specified in this command, the label distribution protocol (LDP) neighbor is configured in the default routing domain.
If this command is not configured, when it is necessary for LDP to change the label it has advertised to a neighbor for some prefix, it will withdraw the previously advertised label before advertising the new label to the neighbor.
For the no form of the command, if the implicit-withdraw keyword is not specified, all configuration information for the specified neighbor reverts to the defaults and the neighbor record is deleted.
Command Modes
Global configuration
Command History
Usage Guidelines
By default, in Cisco IOS Release 12.0(21)ST and later, LDP withdraws the previously advertised label by using a withdraw message before advertising a new label for a FEC. In Cisco IOS releases prior to 12.0(21)ST, LDP did not withdraw a previously advertised label before advertising a new label for a FEC. In those older releases, the new label advertisement served as an implied withdraw and LDP did not send a withdraw message. To cause LDP now to operate as it did in releases before Cisco IOS release 12.0(21)ST—that is, to make LDP now advertise a new label for a FEC without first withdrawing the previously advertised label—use this command's implicit-withdraw keyword.
Router(config)# mpls ldp neighbor 10.10.10.10 implicit-withdrawUsing the implicit-withdraw keyword avoids generating the overhead from an exchange of label withdraw and label release messages.
To disable the implicit-withdraw option, use the no form of the command with the implicit-withdraw keyword. This returns the router to the default, which requires that LDP withdraw the previously advertised label for a FEC before advertising a new label.
Router(config)# no mpls ldp neighbor 10.10.10.10 implicit-withdrawExamples
In the following example, LDP does not send a label-withdraw message to the neighbor whose router ID is 10.10.10.10 when a need exists to change the previously advertised label for a FEC:
Router(config)# mpls ldp neighbor 10.10.10.10 implicit-withdrawRelated Commands
mpls ldp neighbor labels accept
To configure a label switching router (LSR) to filter label distribution protocol (LDP) inbound label bindings from a particular LDP peer, use the mpls ldp neighbor labels accept command in global configuration mode. To disable this feature, use the no form of this command.
mpls ldp neighbor [vrf vpn-name] nbr-address labels accept acl
no mpls ldp neighbor [vrf vpn-name] nbr-address labels accept acl
Syntax Description
Defaults
If the vrf keyword is not specified, the specified LDP neighbor is configured in the default routing domain.
Command Modes
Global configuration
Command History
Usage Guidelines
The specified ACL is used to filter label bindings advertised by the specified neighbor. If the prefix part of the label binding is permitted by the ACL, the router will accept the binding. If the prefix is denied, the router will not accept or store the binding.
This functionality is particularly useful when two different entities manage peer LSRs; that is, the recipient cannot perform filtering by altering the configuration of the sender. This is likely to occur in an Multiprotocol Label Switching (MPLS) virtual private network (VPN) that is using the LDP-based Carrier Supporting Carrier (CSC) feature. In that situation, the backbone carrier may want to restrict the set of label bindings that its provider edge (PE) router may learn from an adjacent customer edge (CE) router that a customer carrier operates.
When inbound label binding filtering is configured, certain configuration changes may require a router to retain bindings that it previously discarded. For example:
•
•
A router does not maintain a record of the set of bindings it previously discarded. Therefore, it cannot ask its neighbors to readvertise just those bindings. In addition, LDP (as defined by RFC 3036) does not provide a means for a router to signal its neighbors to readvertise all label bindings. Consequently, to relearn label bindings following such configuration changes, you must reset the LDP session or sessions by using the clear mpls ldp neighbor command.
Note
Examples
The following example specifies that the LSR accepts inbound label bindings from neighbor 10.19.19.19 in vrf vpn1 for prefixes permitted by the ACL named aclone:
Router(config)# mpls ldp neighbor vrf vpn1 10.19.19.19 label accept acloneRelated Commands
mpls ldp neighbor password
To configure a password key for computing Message Digest 5 (MD5) checksums for the session TCP connection with the specified neighbor, use the mpls ldp neighbor password command in global configuration mode. To disable this option for the specified neighbor, use the no form of this command.
mpls ldp neighbor [vrf vpn-name] ip-addr password [0-7] pswd-string
no mpls ldp neighbor [vrf vpn-name] ip-addr [password [0-7] pswd-string]
Syntax Description
Defaults
Unless the TCP MD5 Signature Option is explicitly configured with the password pswd-string keyword and argument for session TCP connections, the option is not used.
When the vrf keyword is not specified in this command, the label distribution protocol (LDP) neighbor is configured in the default routing domain.
For the no form of the command, if the password keyword is not specified, all configuration information for the specified neighbor reverts to the defaults and the neighbor record is deleted.Command Modes
Global configuration
Command History
Usage Guidelines
You can invoke authentication between two LDP peers, verifying each segment sent on the TCP connection between the peers. To do so, you must configure authentication on both LDP peers using the same password; otherwise, the peer session is not established.
The authentication capability uses the MD5 algorithm. MD5, an algorithm used in conjunction with SNMP, verifies the integrity of the communication, authenticates the origin of the message, and checks for timeliness.
Invoking the mpls ldp neighbor password command causes the generation and checking of the MD5 digest for every segment sent on the TCP connection.
Configuring a password for an LDP neighbor causes an existing LDP session to be torn down and a new session to be established.
If a router has a password configured for a neighbor, but the neighbor router does not have a password configured, a message such as the following appears on the console while the two routers attempt to establish an LDP session:
%TCP-6-BADAUTH: No MD5 digest from [peer's IP address]:11003 to [local router's IP address]:646Similarly, if the two routers have different passwords configured, a message such as the following appears on the console:
%TCP-6-BADAUTH: Invalid MD5 digest from [peer's IP address]:11004 to [local router's IP address]:646Examples
In the following example, the string password1 is configured as the password key for use with MD5 for the neighbor whose router ID is 139.27.0.15:
Router(config)# mpls ldp neighbor 139.27.0.15 password password1In the following example, the string password1 is configured as the password for use with MD5 for the LDP neighbor having router ID 4.4.4.4 in the VPN routing and forwarding instance named vpn1:
Router(config)# mpls ldp neighbor vrf vpn1 4.4.4.4 password password1Related Commands
mpls ldp neighbor targeted
To set up a targeted session with a specified neighbor, use the mpls ldp neighbor targeted command in global configuration mode. To disable a targeted session, use the no form of this command.
mpls ldp neighbor [vrf vpn-name] ip-addr targeted [ldp | tdp]
no mpls ldp neighbor [vrf vpn-name] ip-addr [targeted [ldp | tdp]]
Syntax Description
Defaults
When the targeted keyword is not specified, a targeted session is not set up with the neighbor.
For the no form of the command, if the targeted keyword is not specified, all configuration information for the specified neighbor reverts to the defaults and the neighbor record is deleted.Command Modes
Global configuration
Command History
Usage Guidelines
If you do not specify the label protocol for the targeted session, the label protocol specified with the mpls label protocol command is used. If the mpls label protocol command is not configured, then LDP is used for the targeted session.
Use the mpls ldp neighbor targeted command when you need to set up a targeted session and other means of establishing targeted sessions do not apply, such as configuring mpls ip on a traffic engineering (TE) tunnel or configuring Any Transport over MPLS (AToM) virtual circuits (VCs). For example, you would use this command to set up a targeted session between directly connected MPLS label switch routers (LSRs) when MPLS label forwarding convergence time is an issue.
The mpls ldp neighbor targeted command can improve label convergence time for directly connected neighbor LSRs when the links directly connecting them are down. When the links between the neighbor LSRs are up, both the link and targeted Hellos maintain the LDP session. If the links between the neighbor LSRs go down, the targeted Hellos maintain the session, allowing the LSRs to retain labels learned from each other. When a link directly connecting the LSRs comes back up, the LSRs can immediately reinstall labels for forwarding use without having to reestablish their LDP session and exchange labels.
Examples
In the following example, the router sets up a targeted session with the neighbor 10.10.10.10 using TDP as the label protocol:
Router(config)# mpls ldp neighbor 10.10.10.10 targetedIn the following example, the router sets up a targeted session with the neighbor 10.10.10.10 using LDP as the label protocol:
Router(config)# mpls label protocol ldpRouter(config)# mpls ldp neighbor 10.10.10.10 targetedAnother way to set up a targeted session using LDP without changing the default label protocol is as follows:
Router(config)# mpls ldp neighbor 10.10.10.10 targeted ldpRelated Commands
mpls ldp router-id
To specify a preferred interface for the Label Distribution Protocol (LDP) router ID, use the mpls ldp router-id command in global configuration mode. To disable the interface from being used as the LDP router ID, use the no form of this command.
mpls ldp router-id [vrf vrf-name] interface [force]
no mpls ldp router-id [vrf vrf-name] [interface [force]]
Syntax Description
Command Default
If the mpls ldp router-id command is not executed, the router determines the LDP router ID as follows:
1.
2.
3.
Command Modes
Global configuration
Command History
Usage Guidelines
The mpls ldp router-id command allows you to use 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.
2.
The loopback IP address does not become the router ID of the local LDP ID under the following circumstances:
–
–
If you use a loopback interface, make sure that the IP address for the loopback interface is configured with a /32 network mask. In addition, make sure that the routing protocol in use is configured to advertise the corresponding /32 network.
3.
The router might select a router ID that is not usable in certain situations. For example, the router might select an IP address that the routing protocol cannot advertise to a neighboring router.
The router implements the router ID the next time it is necessary to select an LDP router ID. The effect of the command is delayed until the next time it is necessary to select an LDP router ID, which is typically the next time the interface is shut down or the address is deconfigured.
If you use the force keyword with the mpls ldp router-id command, the router ID takes effect more quickly. However, implementing the router ID depends on the current state of the specified interface:
•
•
The following behaviors apply to the default VRF as well as to VRFs that you explicitly configure with the vrf vrf-name keyword/argument pair:
•
•
•
•
Examples
The following example shows that the POS2/0/0 interface has been specified as the preferred interface for the LDP router ID. The IP address of that interface is used as the LDP router ID.
Router(config)# mpls ldp router-id pos2/0/0The following example shows that the Ethernet 1/0 interface, which is associated with the VRF vpn-1, is the preferred interface. The IP address of the interface is used as the LDP router ID.
Router(config)# mpls ldp router-id vrf vpn-1 eth1/0Related Commands
mpls ldp session protection
To enable Multiprotocol Label Switching (MPLS) Label Distribution Protocol (LDP) autoconfiguration for existing LDP sessions or when new sessions are established, use the mpls ldp session protection command in global configuration mode. To disable this feature, use the no form of this command.
mpls ldp session protection [vrf vpn-name] [for acl] [duration {infinite | seconds}]
no mpls ldp session protection [vrf vpn-name] [for acl] [duration {infinite | seconds}]
Syntax Description
Defaults
LDP sessions are not established.
Command Modes
Global configuration
Command History
Usage Guidelines
This command is not supported under the following circumstances:
•
•
•
If you issue the mpls ldp session protection command without the duration keyword, then session protection is enabled for 86400 seconds (24 hours) meaning that the LDP Targeted Hello Adjacency is retained for 24 hours after a link is lost. This is the default timeout.
If you issue the mpls ldp session protection duration infinite command, then session protection is enabled forever meaning that the LDP Targeted Hello Adjacency is retained forever after a link is lost.
If you issue the mpls ldp session protection duration seconds command, then session protection is enabled for the number of seconds indicated meaning that the LDP Targeted Hello Adjacency is retained for that amount of time. For example, if you issued mpls ldp session protection duration 100, then the LDP Targeted Hello Adjacency is retained for 100 seconds after a link is lost.
Examples
In the following example, MPLS LDP Autoconfiguration is enabled for LDP sessions for peers whose router IDs are listed in access control list rtr4:
Router(config)# mpls ldp session protection for rtr4Related Commands
clear mpls ldp neighbor
Forcibly resets an LDP session.
show mpls ldp neighbor
Displays the contents of the LDP.
mpls load-balance per-label
To enable the load balancing for the tag-to-tag traffic, use the mpls load-balance per-label command in global configuration mode. To return to the default settings, use the no form of this command.
mpls load-balance per-label
no mpls load-balance per-label
Syntax Description
This command has no arguments or keywords.
Defaults
Disabled
Command Modes
Global configuration
Command History
Usage Guidelines
When you enable load balancing for the tag-to-tag traffic, the traffic is balanced based on the incoming label (per prefix) among Multiprotocol Label Switching (MPLS) interfaces. Each MPLS interface supports an equal number of incoming labels.
You can use the show mpls ttfib command to display the incoming label (indicated by an asterisk) that is included in the load balancer.
Examples
This example shows how to enable the load balancing for the tag-to-tag traffic:
Router(config)# mpls load-balance per-labelRouter(config)#This example shows how to disable the load balancing for the tag-to-tag traffic:
Router(config)# no mpls load-balance per-labelRouter(config)#Related Commands
mpls mtu
To set the per-interface Multiprotocol Label Switching (MPLS) maximum transmission unit (MTU) for labeled packets, use the mpls mtu command in interface configuration mode. To restore the default, use the no form of this command.
mpls mtu [override] bytes
no mpls mtu
Syntax Description
Defaults
The default MPLS MTU is the MTU configured for the interface.
Command Modes
Interface configuration
Command History
Usage Guidelines
Usage Guidelines for Cisco IOS Release 12.2(25)S
Caution
If the interface MTU is less than 1524 bytes, you can set the maximum MPLS MTU to 24 bytes more than the interface MTU. For example, if the interface MTU is set to 1510 bytes, then you can set the maximum MPLS MTU to 1534 bytes (1510 + 24).
If the interface MTU is greater than or equal to 1524 bytes, then you can set the maximum MPLS MTU as high as the interface MTU. For example, if the interface MTU is set to 1600 bytes, then you can set the MPLS MTU to a maximum of 1600 bytes. If you set the MPLS MTU higher than the interface MTU, traffic is dropped.
For interfaces that do not allow you to configure the interface MTU value and the interface MTU is
1500 bytes, the MPLS MTU range is 64 to 1524 bytes.If you upgrade to Cisco IOS Release 12.2(25)S from an earlier release and you have an MPLS MTU setting that does not conform to these guidelines, the MPLS MTU setting is not accepted by the system. If this happens, reconfigure the MPLS MTU setting to conform to the guidelines.
Usage Guidelines for Cisco IOS Release 12.2(27)SBC, 12.2(33)SRA, 12.4(11)T, 12.2(33)SXH, and Later Releases
In Cisco IOS Release 12.2(27)SBC, 12.2(33)SRA, 12.4(11)T, 12.2(33)SXH, and later releases, you cannot set the MPLS MTU value larger than the interface MTU value. This is to prevent conditions such as dropped packets, data corruption, and high CPU rates.
•
% Please increase interface mtu to xxxx and then set mpls mtu•
Note
•
Setting the mpls mtu to xxxx on interface x/x, which is higher than the interface MTU xxxx. This could lead to packet forwarding problems including packet drops.Make the MPLS MTU values lower than the interface MTU values.
Caution
•
General Usage Guidelines
•
•
•
•
–
–
•
•
Examples
The following commands set the interface MTU value and MPLS MTU value for a serial interface:
interface Serial4/0mtu 1520ip unnumbered Loopback0mpls mtu 1510mpls traffic-eng tunnelsmpls ipserial restart-delay 0ip rsvp bandwidth 2000 2000The following example sets the maximum labeled packet size for the FastEthernet interface to 1508, which is common in an MPLS core carrying MPLS Virtual Private Network (VPN) traffic:
interface Fastethernet0mpls mtu override 1508Related Commands
mpls netflow egress
To enable Multiprotocol Label Switching (MPLS) egress NetFlow accounting on an interface, use the mpls netflow egress command in interface configuration mode. To disable MPLS egress NetFlow accounting, use the no form of this command.
mpls netflow egress
no mpls netflow egress
Syntax Description
This command has no arguments or keywords.
Defaults
This command is disabled.
Command Modes
Interface configuration
Command History
Usage Guidelines
Use this command to configure the provider edge (PE)-to-customer edge (CE) interface of a PE router.
Examples
The following example shows how to enable MPLS egress NetFlow accounting on the egress PE interface that connects to the CE interface at the destination Virtual Private Network (VPN) site:
Router(config-if)# mpls netflow egressRelated Commands
mpls static binding ipv4
To bind a prefix to a local or remote label, use the mpls static binding ipv4 command in global configuration mode. To remove static prefix/label bindings, use the no form of this command.
mpls static binding ipv4 prefix mask [input | output nexthop] label
no mpls static binding ipv4 [prefix mask [input | output nexthop] label]
Syntax Description
Command Default
If you specify neither input nor output as a keyword, input (local label) is assumed.
For the no form of the command:
•
•
Command Modes
Global configuration
Command History
Usage Guidelines
The mpls static binding ipv4 command pushes bindings into Label Distribution Protocol (LDP). LDP then needs to match the binding with a route in the Routing Information Base (RIB) or Forwarding Information Base (FIB) before installing forwarding information.
The mpls static binding ipv4 command installs the specified bindings into the LDP Label Information Base (LIB). LDP will install the binding labels for forwarding use if or when the binding prefix or mask matches a known route.
Static label bindings are not supported for local prefixes, which are connected networks, summarized routes, default routes, and supernets. These prefixes use implicit-null or explicit-null as the local label.
Examples
In the following output, the mpls static binding ipv4 command configures a static prefix/label binding before the label range is reconfigured to define a range for static assignment. The output of the command indicates that the binding has been accepted, but cannot be used for MPLS forwarding until you configure a range of labels for static assignment that includes the label in question.
Router# configure terminalEnter configuration commands, one per line. End with CNTL/Z.Router(config)# mpls static binding ipv4 10.0.0.0 255.0.0.0 55% Specified label 55 for 10.0.0.0/8 out of configured% range for static labels. Cannot be used for forwarding until% range is extended.Router(config)# endThe following mpls static binding ipv4 commands configure input and output labels for several prefixes:
Router(config)# mpls static binding ipv4 10.0.0.0 255.0.0.0 55Router(config)# mpls static binding ipv4 10.0.0.0 255.0.0.0 output 166.0.0.66 2607Router(config)# mpls static binding ipv4 10.66.0.0 255.255.0.0 input 17Router(config)# mpls static binding ipv4 10.0.0.0 255.0.0.0 output 10.13.0.8 explicit-nullRouter(config)# endThe following show mpls static binding ipv4 command displays the configured bindings:
Router# show mpls static binding ipv459.0.0.0/8: Incoming label: none;Outgoing labels:165.13.0.8 explicit-null107.0.0.0/8: Incoming label: 55 (in LIB)Outgoing labels:166.0.0.66 2607130.66.0.0/16: Incoming label: 17 (in LIB)Outgoing labels: NoneRelated Commands
show mpls forwarding-table
Displays labels currently being used for MPLS forwarding.
show mpls label range
Displays statically configured label bindings.
mpls static binding ipv4 vrf
To bind a prefix to a local label, use the mpls static binding ipv4 vrf command in global configuration mode. To remove static prefix/label bindings, use the no form of this command.
mpls static binding ipv4 vrf vpn-name prefix mask [[input] label]
no mpls static binding ipv4 vrf vpn-name prefix mask [[input] label]
Syntax Description
Defaults
Label bindings are dynamically assigned.
Command Modes
Global configuration
Command History
Usage Guidelines
The vrf keyword can be used only when you configure input labels.
Depending on how you configure VRF aware MPLS static labels, static labels are advertised one of the following ways:
•
•
If you do not specify the input keyword, an input (local) label is assumed.
The no form of the command functions as follows:
•
•
Examples
The following example binds a prefix to local label 17:
Router(config)# mpls static binding ipv4 vrf vpn100 10.66.0.0 10.255.0.0 input 17Related Commands
mpls static crossconnect
To configure a label forwarding information base (LFIB) entry for the specified incoming label and outgoing interface, use the mpls static crossconnect command in global configuration mode. To remove the LFIB entry, use the no form of this command.
mpls static crossconnect inlabel out-interface [nexthop] {outlabel | explicit-null | implicit-null}
no mpls static crossconnect inlabel out-interface [nexthop] {outlabel | explicit-null | implicit-null}
Syntax Description
Command Default
This command has no default behavior or values.
Command Modes
Global configuration
Command History
Usage Guidelines
You must specify the optional nexthop keyword for multiaccess interfaces.
Examples
In the following output, the mpls static crossconnect command configures a crossconnect from incoming label 45 to outgoing label 46 out interface pos5/0:
Router# configure terminalEnter configuration commands, one per line. End with CNTL/Z.Router(config)# mpls static crossconnect 45 pos5/0 46Related Commands
mpls traffic-eng
To configure a router running Intermediate System-to-Intermediate System (IS-IS) so that it floods Multiprotocol Label Switching (MPLS) traffic engineering (TE) link information into the indicated IS-IS level, use the mpls traffic-eng command in router configuration mode. To disable the flooding of MPLS TE link information into the indicated IS-IS level, use the no form of this command.
mpls traffic-eng {level-1 | level-2}
no mpls traffic-eng {level-1 | level-2}
Syntax Description
level-1
Floods MPLS TE link information into IS-IS level 1.
level-2
Floods MPLS TE link information into IS-IS level 2.
Defaults
Flooding is disabled.
Command Modes
Router configuration
Command History
Usage Guidelines
This command, which is part of the routing protocol tree, causes link resource information (such as available bandwidth) for appropriately configured links to be flooded in the IS-IS link-state database.
Examples
The following example shows how to configure MPLS TE link information flooding for IS-IS level 1:
Router(config-router)# mpls traffic-eng level-1Related Commands
mpls traffic-eng router-id
Specifies that the traffic engineering router identifier for the node is the IP address associated with a given interface.
mpls traffic-eng administrative-weight
To override the Interior Gateway Protocol (IGP) administrative weight (cost) of the link, use the mpls traffic-eng administrative-weight command in interface configuration mode. To disable the override, use the no form of this command.
mpls traffic-eng administrative-weight weight
no mpls traffic-eng administrative-weight
Syntax Description
Defaults
IGP cost of the link.
Command Modes
Interface configuration
Command History
Examples
The following example shows how to override the IGP cost of the link and set the cost to 20:
Router(config-if)# mpls traffic-eng administrative-weight 20Related Commands
mpls traffic-eng attribute-flags
Sets the user-specified attribute flags for an interface.
mpls traffic-eng area
To configure a router running Open Shortest Path First (OSPF) Multiprotocol Label Switching (MPLS) so that it floods traffic engineering for the indicated OSPF area, use the mpls traffic-eng area command in router configuration mode. To disable flooding of traffic engineering for the indicated OSPF area, use the no form of this command.
mpls traffic-eng area number
no mpls traffic-eng area number
Syntax Description
Defaults
Flooding is disabled.
Command Modes
Router configuration
Command History
Usage Guidelines
This command is in the routing protocol configuration tree and is supported for both OSPF and IS-IS. The command affects the operation of MPLS traffic engineering only if MPLS traffic engineering is enabled for that routing protocol instance. Currently, only a single level can be enabled for traffic engineering.
Examples
The following example shows how to configure a router running OSPF MPLS to flood traffic engineering for OSPF 0:
Router(config-router)# mpls traffic-eng area 0Related Commands
mpls traffic-eng attribute-flags
To set the user-specified attribute flags for the interface, use the mpls traffic-eng attribute-flags command in interface configuration mode. To disable the user-specified attribute flags for the interface, use the no form of this command.
mpls traffic-eng attribute-flags attributes
no mpls traffic-eng attribute-flags
Syntax Description
Defaults
0x0
Command Modes
Interface configuration
Command History
Usage Guidelines
This command assigns attributes to a link so that tunnels with matching attributes (represented by their affinity bits) prefer this link instead of others that do not match.
The interface is flooded globally so that it can be used as a tunnel head-end path selection criterion.
Examples
The following example shows how to set the attribute flags to 0x0101:
Router(config-if)# mpls traffic-eng attribute-flags 0x0101Related Commands
mpls traffic-eng auto-bw timers
To enable automatic bandwidth adjustment for a platform and to start output rate sampling for tunnels configured for automatic bandwidth adjustment, use the mpls traffic-eng auto-bw timers command in global configuration mode. To disable automatic bandwidth adjustment for the platform, use the no form of this command.
mpls traffic-eng auto-bw timers [frequency seconds]
no mpls traffic-eng auto-bw timers
Syntax Description
Command Default
When the optional frequency keyword is not specified, the sampling interval is 300 seconds (5 minutes).
Command Modes
Global configuration
Command History
Usage Guidelines
The mpls traffic-eng auto-bw timers command enables automatic bandwidth adjustment on a platform by causing traffic engineering to periodically sample the output rate for each tunnel configured for bandwidth adjustment.
The no mpls traffic-eng auto-bw timers command disables automatic bandwidth adjustment for a platform by terminating the output rate sampling and bandwidth adjustment for tunnels configured for adjustment. In addition, the no form of the command restores the configured bandwidth for each tunnel where "configured bandwidth" is determined as follows:
•
•
Examples
The following example shows how to designate that for each Multiprotocol Label Switching (MPLS) traffic engineering tunnel, the output rate is sampled once every 10 minutes (every 600 seconds):
Router(config)# mpls traffic-eng auto-bw timers frequency 600Related Commands
