Label Advertisement Control (Outbound Filtering); Label Acceptance Control (Inbound Filtering) - Cisco ASR 9000 Series Configuration Manual

Label Advertisement Control (Outbound Filtering)

peer was able to restore its state successfully. It reinstates the corresponding forwarding state entries and
receives binding from the restarting peer. When the recovery timer expires, any forwarding state that is still
marked as stale is deleted.
If the restarting LSR fails to recover (restart), the restarting LSR forwarding state and entries will eventually
timeout and is deleted, while neighbor-related forwarding states or entries are removed by the Peer LSR on
expiration of the reconnect or recovery timers.
Related Topics
Setting Up LDP NSF Using Graceful Restart, on page 33
Configuring LDP Nonstop Forwarding with Graceful Restart: Example, on page 54
Label Advertisement Control (Outbound Filtering)
By default, LDP advertises labels for all the prefixes to all its neighbors. When this is not desirable (for
scalability and security reasons), you can configure LDP to perform outbound filtering for local label
advertisement for one or more prefixes to one more peers. This feature is known as LDP outbound label
filtering, or local label advertisement control.
Related Topics
Configuring Label Advertisement Control (Outbound Filtering), on page 27
Configuring Label Advertisement (Outbound Filtering): Example, on page 53

Label Acceptance Control (Inbound Filtering)

By default, LDP accepts labels (as remote bindings) for all prefixes from all peers. LDP operates in liberal
label retention mode, which instructs LDP to keep remote bindings from all peers for a given prefix. For
security reasons, or to conserve memory, you can override this behavior by configuring label binding acceptance
for set of prefixes from a given peer.
The ability to filter remote bindings for a defined set of prefixes is also referred to as LDP inbound label
filtering.
Inbound filtering can also be implemented using an outbound filtering policy; however, you may not be
Note
able to implement this system if an LDP peer resides under a different administration domain. When both
inbound and outbound filtering options are available, we recommend that you use outbound label filtering.
Related Topics
Configuring Label Acceptance Control (Inbound Filtering), on page 35
Configuring Label Acceptance (Inbound Filtering): Example, on page 55
Cisco ASR 9000 Series Aggregation Services Router MPLS Configuration Guide, Release 4.3.x
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Implementing MPLS Label Distribution Protocol
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