Applying Import and Export Policies

Inbound filtering (import policy) allows a route policy to control the label bindings that an LSR accepts from its peers. An import policy can accept or reject label bindings received from LDP peers. Label bindings can be filtered based on the following:

neighbor — match on bindings received from the specified peer
prefix-list — match on bindings with the specified prefix or prefixes

Outbound filtering (export policy) allows a route policy to control the label bindings advertised by the LSR to its peers. Label bindings can be filtered based on the following:

all — all local subnets by specifying direct as the match protocol
prefix-list — match on bindings with the specified prefix/prefixes

Import or export policies must already exist before they are applied to LDP. Policies are configured in the config>router>policy-options context. See the ‟Route Policies” section in the 7705 SAR Router Configuration Guide for details.

Note:

The 7705 SAR supports a specific number of labels, which varies by platform and software release. If the number of labels is exceeded for a specific protocol (for example, LDP or RSVP), a log message will appear by default in logs 99 and 100. The log message states the affected protocol and the label count that was exceeded. For example: ‟mpls_label_ilm_helper: XXXX XXX XXXX limit reached max obj count of YYYY”.
For the LDP protocol, when the label count is exceeded, LDP sessions will be shut down and all labels will be removed. To recover the LDP sessions, perform a shutdown/no shutdown combination of commands in the config>router>ldp context.

Use the following CLI syntax to apply import or export policies:

CLI Syntax:

config>router>ldp
    import policy-name [policy-name...(up to 5 max)]
    export policy-name [policy-name...(up to 5 max)]

Example:

config>router>ldp
config>router>ldp# import LDP-import
config>router>ldp# export LDP-export
config>router>ldp# exit
config>router#

The following example displays the import and export policy configuration output.

ALU-1>config>router>ldp# info
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            export "LDP-export"
            import "LDP-import"
            interface-parameters
            exit
            targeted-session
            exit
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