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Multiprotocol Label Switching (MPLS) Label Distribution Protocol (LDP) supports inbound label binding filtering. You can use the MPLS LDP Inbound Label Binding Filtering feature to configure access control lists (ACLs) for controlling the label bindings a label switch router (LSR) accepts from its peer LSRs.
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.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.
Inbound label binding filtering does not support extended access control lists (ACLs); it only supports standard ACLs.
The MPLS LDP Inbound Label Binding Filtering feature can be used to control the amount of memory used to store Label Distribution Protocol (LDP) label bindings advertised by other devices. For example, in a simple Multiprotocol Label Switching (MPLS) Virtual Private Network (VPN) environment, the VPN provider edge (PE) devices might require label switched paths (LSPs) only to their peer PE devices (that is, they do not need LSPs to core devices). Inbound label binding filtering enables a PE device to accept labels only from other PE devices.
Perform this task to configure a device for inbound label filtering. The following configuration allows the device to accept only the label for prefix 25.0.0.2 from the Label Distribution Protocol (LDP) neighbor device 10.12.12.12.
1.
enable
2.
configure terminal
3.
ip access-list standard
access-list-number
4.
permit {source [source-wildcard] |
any} [log]
5.
exit
6.
mpls ldp neighbor [vrf
vpn-name]
nbr-address
labels accept
acl
7.
end
If inbound filtering is enabled, perform the following tasks to verify that inbound label bindings are filtered.
1.
enable
2.
show mpls ldp neighbor [vrf
vpn-name] [address |
interface] [detail]
3.
show ip access-list [access-list-number |
access-list-name]
4.
show mpls ldp bindings
5.
exit
In the following example, the mpls ldp neighbor labels accept command is configured with an access control list to filter label bindings received on sessions with the neighbor 10.110.0.10.
Label bindings for prefixes that match 10.b.c.d are accepted, where b is less than or equal to 63, and c and d can be any integer between 0 and 128. Other label bindings received from 10.110.0.10 are rejected.
Device# configure terminal Device(config)# access-list 1 permit 10.63.0.0 0.63.255.255 Device(config)# mpls ldp neighbor 10.110.0.10 labels accept 1 Device(config)# end
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.
Device# show mpls ldp bindings neighbor 10.110.0.10
tib entry: 10.2.0.0/16, rev 4
remote binding: tsr: 10.110.0.10:0, tag: imp-null
tib entry: 10.43.0.0/16, rev 6
remote binding: tsr: 10.110.0.10:0, tag: 16
tib entry: 10.52.0.0/16, rev 8
remote binding: tsr: 10.110.0.10:0, tag: imp-null
Related Topic |
Document Title |
|---|---|
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Cisco IOS commands |
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MPLS commands |
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MPLS Label Distribution Protocol (LDP) |
“MPLS Label Distribution Protocol” module in the MPLS Label Distribution Protocol Configuration Guide |
MIB |
MIBs Link |
|---|---|
|
LDP Specification, draft-ietf-mpls-ldp-08.txt |
To locate and download MIBs for selected platforms, Cisco software releases, and feature sets, use Cisco MIB Locator found at the following URL: |
RFC |
Title |
|---|---|
|
RFC 3036 |
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|
RFC 3037 |
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.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.
|
Feature Name |
Releases |
Feature Information |
|---|---|---|
|
MPLS LDP Inbound Label Binding Filtering |
12.0(26)S 12.2(25)S 15.2(1)SY |
You can use the MPLS LDP Inbound Label Binding Filtering feature to configure access control lists (ACLs) for controlling the label bindings a label switch router (LSR) accepts from its peer LSRs. In Cisco IOS Release 12.0(26)S, this feature was introduced on the Cisco 7200. This feature was integrated into Cisco IOS Release 12.2(25)S for the Cisco 7500 series router. In 15.2(1)SY, the feature was integrated into Cisco IOS Release 15.2(2)SY. The following commands were introduced or modified: clear mpls ldp neighbor , mpls ldp neighbor labels accept , show mpls ldp neighbor |
carrier supporting carrier—A situation where one service provider allows another service provider to use a segment of its backbone network. The service provider that provides the segment of the backbone network to the other provider is called the backbone carrier. The service provider that uses the segment of the backbone network is called the customer carrier.
CE device—customer edge device. A device that is part of a customer network and that interfaces to a provider edge (PE) device.
inbound label binding filtering—Allows label switch routers (LSRs) to control which label bindings it will accept from its neighboring LSRs. Consequently, an LSR does not accept or store some label bindings that its neighbors advertise.
label—A short fixed-length identifier that tells switching nodes how to forward data (packets or cells).
label binding—An association between a destination prefix and a label.
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