Details Of Session Protection - Cisco NCS 5500 Series Configuration Manual

Mpls ios xr release 6.2.x

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Implementing MPLS Label Distribution Protocol

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.

Details of Session Protection

LDP session protection lets you configure LDP to automatically protect sessions with all or a given set of

peers (as specified by peer-acl). When configured, LDP initiates backup targeted hellos automatically for

neighbors for which primary link adjacencies already exist. These backup targeted hellos maintain LDP

sessions when primary link adjacencies go down.

The Session Protection figure illustrates LDP session protection between neighbors R1 and R3. The primary

link adjacency between R1 and R3 is directly connected link and the backup; targeted adjacency is maintained

between R1 and R3. If the direct link fails, LDP link adjacency is destroyed, but the session is kept up and

running using targeted hello adjacency (through R2). When the direct link comes back up, there is no change

in the LDP session state and LDP can converge quickly and begin forwarding MPLS traffic.

Figure 5: Session Protection

When LDP session protection is activated (upon link failure), protection is maintained for an unlimited

Note

period time.

MPLS Configuration Guide for Cisco NCS 5500 Series Routers, IOS XR Release 6.2.x

Details of Session Protection

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