[j-nsp] LDP flaps specifically present on ACX Juniper routers (ACX4000 and ACX1100)

[joel ahumuza]

Hi All,

We are experiencing an issue with ACX routers running on 12.3X54-D20.7
where the LDP sessions are continuously flapping, the logs indicate the
following;

Apr 21 03:36:31  hostname rpd[2299]: RPD_LDP_SESSIONDOWN: LDP session
x.x.x.x is down, reason: hold time expired
Apr 21 03:36:34  hostname rpd[2299]: RPD_LDP_NBRDOWN: LDP neighbor x.x.x.x
(lo0.0) is down
Apr 21 03:36:38  hostname rpd[2299]: RPD_LDP_NBRDOWN: LDP neighbor x.x.x.x
(lo0.0) is down
Apr 21 03:36:38  hostname rpd[2299]: RPD_LDP_SESSIONDOWN: LDP session
x.x.x.x is down, reason: all adjacencies down
Apr 21 03:55:34  hostname rpd[2299]: RPD_LDP_SESSIONDOWN: LDP session
x.x.x.x is down, reason: received notification from peer
Apr 21 03:55:34  hostname rpd[2299]: RPD_LDP_SESSIONDOWN: LDP session
x.x.x.x is down, reason: received notification from peer
Apr 21 03:55:35  hostname rpd[2299]: RPD_LDP_SESSIONDOWN: LDP session
x.x.x.x is down, reason: received notification from peer
Apr 21 03:55:35  hostname rpd[2299]: RPD_LDP_SESSIONDOWN: LDP session
x.x.x.x is down, reason: received notification from peer

The physical connections are okay, no flaps or errors on the p2p connections
We are running ISIS as the IGP, whose adjacency is stable.

Actions taken from our team was;
- Increase the hold time setting on the ldp enabled interfaces.
- Increase the time interval on the same ldp enabled interfaces.
- setting the ldp session protection setting on the ldp enabled loopback
interface.

Unfortunately the actions did not yield much since the flaps have been
ongoing.

Anyone have any Idea on what the problem / solution might be?

-- 
Blessings,

AJ.
SkypeID - jl.hmz
ahumuza-joel.blogspot.ug