LDP Session Alternates Between Up and Down States

Fault Description

An LDP session alternates between Up and Down states when you add, change, or delete the LDP GR timer, LDP MTU, LDP authentication, LDP Keepalive timer, or LDP transport address.

Procedure

Run the display this command in the LDP view to check whether LDP GR or LDP MTU is configured.
- If the following information is displayed:
```
mpls ldp
 graceful-restart
```
  LDP GR is configured.
- If the following information is displayed:
```
mpls ldp
 mtu-signalling apply-tlv
```
  LDP MTU is configured.
- If information similar to the following is displayed:
```
mpls ldp
 md5-password cipher 2.2.2.2 %^%#="+W)uY+N$8',5Lhem%H4ZyT@h{24%Lm6A'HAnS!%^%#
```
  or
```
mpls ldp
 authentication key-chain peer 2.2.2.2 name kc1
```
  LDP authentication is configured.
Run the display this command in the interface view to check whether the LDP Keepalive timer or LDP transport address is configured.
- If information similar to the following is displayed:
```
mpls ldp
mpls ldp timer keepalive-hold 30
```
  The LDP Keepalive timer is configured.
- If information similar to the following is displayed:
```
mpls ldp
mpls ldp transport-address interface
```
  The LDP transport address is configured.
After the preceding configurations are complete, wait for 10s and the LDP session becomes stable.