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This document describes the Cisco MPLS Static Labels feature. The MPLS Static Labels feature provides the means to configure statically:
Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table at the end of this module.
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The network must support the following Cisco IOS features before you enable MPLS static labels:
Generally, label switching routers (LSRs) dynamically learn the labels they should use to label-switch packets by means of label distribution protocols that include:
To use a learned label to label-switch packets, an LSR installs the label into its Label Forwarding Information Base (LFIB).
The MPLS Static Labels feature provides the means to configure statically:
Static bindings between labels and IPv4 prefixes can be configured to support MPLS hop-by-hop forwarding through neighbor routers that do not implement LDP label distribution.
Static crossconnects can be configured to support MPLS Label Switched Path (LSP) midpoints when neighbor routers do not implement either the LDP or RSVP label distribution, but do implement an MPLS forwarding path.
To configure MPLS static prefix/label bindings, use the following commands beginning in global configuration mode:
1.
enable
2.
configure
terminal
3.
mpls
label
range
min-label
max-label
[static min-static-label max-static-label]
4.
mpls
static
binding
ipv4
prefix
mask
[input| output nexthop] label
To verify the configuration for MPLS static prefix/label bindings, use this procedure:
1. Enter show mpls label range command. The output shows that the new label ranges do not take effect until a reload occurs:
2. Enter the show mpls static binding ipv4 command to show the configured static prefix/label bindings:
3. Use the show mpls forwarding-table command to determine which static prefix/label bindings are currently in use for MPLS forwarding.
Step 1 |
Enter show mpls label range command. The output shows that the new label ranges do not take effect until a reload occurs: Example: Router# show mpls label range Downstream label pool: Min/Max label: 16/100000 [Configured range for next reload: Min/Max label: 200/100000] Range for static labels: Min/Max/Number: 16/199
The following output from the show mpls label range command, executed after a reload, indicates that the new label ranges are in effect: Example: Router# show mpls label range Downstream label pool: Min/Max label: 200/100000 Range for static labels: Min/Max/Number: 16/199
|
Step 2 |
Enter the show mpls static binding ipv4 command to show the configured static prefix/label bindings: Example: Router# show mpls static binding ipv4 10.17.17.17/32: Incoming label: 251 (in LIB) Outgoing labels: 10.0.0.1 18 10.18.18.18/32: Incoming label: 201 (in LIB) Outgoing labels: 10.0.0.1 implicit-null
|
Step 3 |
Use the show mpls forwarding-table command to determine which static prefix/label bindings are currently in use for MPLS forwarding. Example: Router# show mpls forwarding-table Local Outgoing Prefix Bytes tag Outgoing Next Hop tag tag or VC or Tunnel Id switched interface 201 Pop tag 10.18.18.18/32 0 PO1/1/0 point2point 2/35 10.18.18.18/32 0 AT4/1/0.1 point2point 251 18 10.17.17.17/32 0 PO1/1/0 point2point |
To configure MPLS static crossconnects, use the following command beginning in global configuration mode:
1.
enable
2.
configure
terminal
3.
mpls
label
range
min-label
max-label
[static min-static-label max-static-label]
4.
mpls
static
binding
ipv4
prefix
mask
[input| output nexthop] label
To verify the configuration for MPLS static crossconnects, use this procedure:
1. Use the show mpls static crossconnect command to display information about crossconnects that have been configured:
Example: Router# show mpls static crossconnect Local Outgoing Outgoing Next Hop label label interface 34 22 pos3/0/0 point2point (in LFIB) |
To monitor and maintain MPLS static labels, use one or more of the following commands:
1.
enable
2.
show
mpls
forwarding-table
3.
show
mpls
label
range
4.
show
mpls
static
binding
ipv4
5.
show
mpls
static
crossconnect
In the following output, the mpls label range command reconfigures the range used for dynamically assigned labels from 16 to 100000 to 200 to 100000 and configures a static label range of 16 to 199.
Router# configure terminal Enter configuration commands, one per line. End with CNTL/Z. Router(config)# mpls label range 200 100000 static 16 199 % Label range changes take effect at the next reload. Router(config)# end
In the following output, the show mpls label range command indicates that the new label ranges do not take effect until a reload occurs:
Router# show mpls label range Downstream label pool: Min/Max label: 16/100000 [Configured range for next reload: Min/Max label: 200/100000] Range for static labels: Min/Max/Number: 16/199
In the following output, the show mpls label range command, executed after a reload, indicates that the new label ranges are in effect:
Router# show mpls label range Downstream label pool: Min/Max label: 200/100000 Range for static labels: Min/Max/Number: 16/199
In the following output, the mpls static binding ipv4 commands configure static prefix/label bindings. They also configure input (local) and output (remote) labels for various prefixes:
Router# configure terminal Enter configuration commands, one per line. End with CNTL/Z. Router(config)# mpls static binding ipv4 10.0.0.0 255.0.0.0 55 Router(config)# mpls static binding ipv4 10.0.0.0 255.0.0.0 output 10.0.0.66 2607 Router(config)# mpls static binding ipv4 10.6.0.0 255.255.0.0 input 17 Router(config)# mpls static binding ipv4 10.0.0.0 255.0.0.0 output 10.13.0.8 explicit-null Router(config)# end
In the following output, the show mpls static binding ipv4 command displays the configured static prefix/label bindings:
Router# show mpls static binding ipv4 10.0.0.0/8: Incoming label: none; Outgoing labels: 10.13.0.8 explicit-null 10.0.0.0/8: Incoming label: 55 (in LIB) Outgoing labels: 10.0.0.66 2607 10.66.0.0/16: Incoming label: 17 (in LIB) Outgoing labels: None
In the following output, the mpls static crossconnect command configures a crossconnect from incoming label 34 to outgoing label 22 out interface pos3/0/0:
Router# configure terminal Enter configuration commands, one per line. End with CNTL/Z. Router(config)# mpls static crossconnect 34 pos3/0/0 22 Router(config)# end
In the following output, the show mpls static crossconnect command displays the configured crossconnect:
Router# show mpls static crossconnect Local Outgoing Outgoing Next Hop label label interface 34 22 pos3/0/0 point2point (in LFIB)
Related Topic |
Document Title |
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IPv6 addressing and connectivity |
IPv6 Configuration Guide |
Cisco IOS commands |
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IPv6 commands |
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Cisco IOS IPv6 features |
Standard/RFC |
Title |
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RFCs for IPv6 |
IPv6 RFCs |
Description |
Link |
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The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.
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BGP --Border Gateway Protocol. The predominant interdomain routing protocol used in IP networks.
Border Gateway Protocol --See BGP.
FIB --Forwarding Information Base. A table that contains a copy of the forwarding information in the IP routing table.
Forwarding Information Base --See FIB.
label --A short, fixed-length identifier that tells switching nodes how the data (packets or cells) should be forwarded.
label binding --An association between a label and a set of packets, which can be advertised to neighbors so that a label switched path can be established.
Label Distribution Protocol --See LDP.
Label Forwarding Information Base --See LFIB.
label imposition --The act of putting the first label on a packet.
label switching router --See LSR.
LDP --Label Distribution Protocol. The protocol that supports MPLS hop-by-hop forwarding by distributing bindings between labels and network prefixes.
LFIB --Label Forwarding Information Base. A data structure in which destinations and incoming labels are associated with outgoing interfaces and labels.
LSR --label switching router. A Layer 3 router that forwards a packet based on the value of an identifier encapsulated in the packet.
MPLS --Multiprotocol Label Switching. An industry standard on which label switching is based.
MPLS hop-by-hop forwarding --The forwarding of packets along normally routed paths using MPLS forwarding mechanisms.
Multiprotocol Label Switching --See MPLS.
Resource Reservation Protocol --See RSVP.
RIB --Routing Information Base. A common database containing all the routing protocols running on a router.
Routing Information Base --See RIB.
RSVP --Resource Reservation Protocol. A protocol for reserving network resources to provide quality of service guarantees to application flows.
traffic engineering --Techniques and processes used to cause routed traffic to travel through the network on a path other than the one that would have been chosen if standard routing methods were used.
Virtual Private Network --See VPN.
VPN --Virtual Private Network. A network that enables IP traffic to use tunneling to travel securely over a public TCP/IP network.