MPLS LDP FLAPPING CONTINUOUSLY

rawat.umed · ‎01-08-2014

Hi

We are facing issue of ldp flapping continously in our mpls network.

3: Jan 9 12:47:12 IST: %LDP-5-NBRCHG: LDP Neighbor 10.135.254.21:0 (0) is DOWN (Received error notification from peer: KeepAlive expired)

1046264: Jan 9 12:47:13 IST: %LDP-5-GR: GR session 10.135.254.21:0 (inst. 34): starting graceful recovery

1046265: Jan 9 12:47:13 IST: %LDP-5-NBRCHG: LDP Neighbor 10.135.254.21:0 (34) is UP

1046266: Jan 9 12:47:58 IST: %LDP-5-GR: GR session 10.135.254.27:0 (inst. 11): completed graceful recovery

1046267: Jan 9 12:49:13 IST: %LDP-5-GR: GR session 10.135.254.21:0 (inst. 34): completed graceful recovery

1046268: Jan 9 12:50:08 IST: %LDP-5-GR: GR session 10.135.254.27:0 (inst. 11): interrupted--recovery pending

1046269: Jan 9 12:50:08 IST: %LDP-5-NBRCHG: LDP Neighbor 10.135.254.27:0 (0) is DOWN (Session KeepAlive Timer expired)

1046270: Jan 9 12:50:09 IST: %LDP-5-GR: GR session 10.135.254.27:0 (inst. 9): starting graceful recovery

1046271: Jan 9 12:50:09 IST: %LDP-5-NBRCHG: LDP Neighbor 10.135.254.27:0 (9) is UP

1046272: Jan 9 12:51:23 IST: %LDP-5-GR: GR session 10.135.254.21:0 (inst. 34): interrupted--recovery pending

1046273: Jan 9 12:51:23 IST: %LDP-5-NBRCHG: LDP Neighbor 10.135.254.21:0 (0) is DOWN (Received error notification from peer: KeepAlive expired)

1046274: Jan 9 12:51:26 IST: %LDP-5-GR: GR session 10.135.254.21:0 (inst. 38): starting graceful recovery

1046275: Jan 9 12:51:26 IST: %LDP-5-NBRCHG: LDP Neighbor 10.135.254.21:0 (38) is UP

1046276: Jan 9 12:51:26 IST: %OSPF-5-ADJCHG: Process 1, Nbr 10.134.254.2 on GigabitEthernet1/8 from FULL to DOWN, Neighbor Down: BFD node down

1046277: Jan 9 12:51:29 IST: %OSPF-5-ADJCHG: Process 1, Nbr 10.134.254.2 on GigabitEthernet1/8 from LOADING to FULL, Loading Done

1046278: Jan 9 12:52:09 IST: %LDP-5-GR: GR session 10.135.254.27:0 (inst. 9): completed graceful recovery

1046279: Jan 9 12:53:26 IST: %LDP-5-GR: GR session 10.135.254.21:0 (inst. 38): completed graceful recovery

1046280: Jan 9 12:54:19 IST: %LDP-5-GR: GR session 10.135.254.27:0 (inst. 9): interrupted--recovery pending

1046281: Jan 9 12:54:19 IST: %LDP-5-NBRCHG: LDP Neighbor 10.135.254.27:0 (0) is DOWN (Session KeepAlive Timer expired)

1046282: Jan 9 12:54:22 IST: %LDP-5-GR: GR session 10.135.254.27:0 (inst. 11): starting graceful recovery

1046283: Jan 9 12:54:22 IST: %LDP-5-NBRCHG: LDP Neighbor 10.135.254.27:0 (11) is UP

1046284: Jan 9 12:55:36 IST: %LDP-5-GR: GR session 10.135.254.21:0 (inst. 38): interrupted--recovery pending

1046285: Jan 9 12:55:36 IST: %LDP-5-NBRCHG: LDP Neighbor 10.135.254.21:0 (0) is DOWN (Received error notification from peer: KeepAlive expired)

1046286: Jan 9 12:55:37 IST: %LDP-5-GR: GR session 10.135.254.21:0 (inst. 34): starting graceful recovery

1046287: Jan 9 12:55:37 IST: %LDP-5-NBRCHG: LDP Neighbor 10.135.254.21:0 (34) is UP

1046288: Jan 9 12:56:18 IST: %OSPF-5-ADJCHG: Process 1, Nbr 10.134.254.2 on GigabitEthernet1/8 from FULL to DOWN, Neighbor Down: BFD node down

1046289: Jan 9 12:56:22 IST: %LDP-5-GR: GR session 10.135.254.27:0 (inst. 11): completed graceful recovery

1046290: Jan 9 12:56:24 IST: %OSPF-5-ADJCHG: Process 1, Nbr 10.134.254.2 on GigabitEthernet1/8 from LOADING to FULL, Loading Done

1046291: Jan 9 12:57:37 IST: %LDP-5-GR: GR session 10.135.254.21:0 (inst. 34): completed graceful recovery

1046292: Jan 9 12:58:32 IST: %LDP-5-GR: GR session 10.135.254.27:0 (inst. 11): interrupted--recovery pending

1046293: Jan 9 12:58:32 IST: %LDP-5-NBRCHG: LDP Neighbor 10.135.254.27:0 (0) is DOWN (Session KeepAlive Timer expired)

1046294: Jan 9 12:58:33 IST: %LDP-5-GR: GR session 10.135.254.27:0 (inst. 9): starting graceful recovery

1046295: Jan 9 12:58:33 IST: %LDP-5-NBRCHG: LDP Neighbor 10.135.254.27:0 (9) is UP

1046296: Jan 9 12:59:47 IST: %LDP-5-GR: GR session 10.135.254.21:0 (inst. 34): interrupted--recovery pending

1046297: Jan 9 12:59:47 IST: %LDP-5-NBRCHG: LDP Neighbor 10.135.254.21:0 (0) is DOWN (Received error notification from peer: KeepAlive expired)

1046298: Jan 9 12:59:47 IST: %LDP-5-GR: GR session 10.135.254.21:0 (inst. 38): starting graceful recovery

1046299: Jan 9 12:59:47 IST: %LDP-5-NBRCHG: LDP Neighbor 10.135.254.21:0 (38) is UP

1046300: Jan 9 13:00:33 IST: %LDP-5-GR: GR session 10.135.254.27:0 (inst. 9): completed graceful recovery

1046301: Jan 9 13:01:47 IST: %LDP-5-GR: GR session 10.135.254.21:0 (inst. 38): completed graceful recovery

1046302: Jan 9 13:02:43 IST: %LDP-5-GR: GR session 10.135.254.27:0 (inst. 9): interrupted--recovery pending

1046303: Jan 9 13:02:43 IST: %LDP-5-NBRCHG: LDP Neighbor 10.135.254.27:0 (0) is DOWN (Session KeepAlive Timer expired)

1046304: Jan 9 13:02:44 IST: %LDP-5-GR: GR session 10.135.254.27:0 (inst. 11): starting graceful recovery

1046305: Jan 9 13:02:44 IST: %LDP-5-NBRCHG: LDP Neighbor 10.135.254.27:0 (11) is UP

1046306: Jan 9 13:03:57 IST: %LDP-5-GR: GR session 10.135.254.21:0 (inst. 38): interrupted--recovery pending

1046307: Jan 9 13:03:57 IST: %LDP-5-NBRCHG: LDP Neighbor 10.135.254.21:0 (0) is DOWN (Received error notification from peer: KeepAlive expired)

We have checked the interfaces and no flapping were there in that.

Also when we gave the cmd

SUR_COR#sh mpls ldp nei 10.135.254.27

Peer LDP Ident: 10.135.254.27:0; Local LDP Ident 10.135.254.2:0

TCP connection: 10.135.254.27.37737 - 10.135.254.2.646

State: Oper; Msgs sent/rcvd: 2276/2; Downstream

Up time: 00:00:08

LDP discovery sources:

Targeted Hello 10.135.254.2 -> 10.135.254.27, active, passive

no ip are there in targeted hello .

while at the other end

SUR_PE1#sh mpls ldp nei 10.135.254.2

Peer LDP Ident: 10.135.254.2:0; Local LDP Ident 10.135.254.27:0

TCP connection: 10.135.254.2.646 - 10.135.254.27.37737

State: Oper; Msgs sent/rcvd: 2277/2278; Downstream

Up time: 00:02:00

LDP discovery sources:

Targeted Hello 10.135.254.27 -> 10.135.254.2, active, passive

Addresses bound to peer LDP Ident:

10.135.254.2 10.135.7.233 10.135.7.249 10.135.7.229

10.135.7.237 10.135.7.217 10.135.7.213 10.135.7.201

10.135.7.6 10.135.7.225 10.135.7.197 10.134.1.26

10.135.7.10 10.135.7.26 10.134.1.50 10.135.7.221

10.135.7.193 10.135.7.245 172.18.123.145 172.18.123.221

10.134.1.34 10.135.7.241 10.135.7.177 10.134.1.30

10.135.7.205 10.135.7.209 10.135.7.14 10.135.7.17

10.135.7.21

we are getting intermediate ip addresses.

Any one can help regarding this

Rivalino Tamaela · ‎01-09-2014

From show command we can see that SUR_COR receives less LDP messages, could be dropped along the path. It sent 2276 but receives only 2 packets from its neighbor.

SUR_COR#sh mpls ldp nei 10.135.254.27

Peer LDP Ident: 10.135.254.27:0; Local LDP Ident 10.135.254.2:0

TCP connection: 10.135.254.27.37737 - 10.135.254.2.646

State: Oper; Msgs sent/rcvd: 2276/2; Downstream

Up time: 00:00:08

LDP discovery sources:

Targeted Hello 10.135.254.2 -> 10.135.254.27, active, passive

While SUR_PE1 could send and receive LDP messages correctly. Need to investigate if there is any congestion one way from 10.135.254.2 to 10.135.254.27.

HTH,

Rivalino

Ashish Panda · ‎01-10-2014

Hi Umed,

Folwing are some suggestions

- Try to check match LDP configuration if you have changed LDP timers

- Try to check the negotiated MTU for the TCP session is supported on the path

- Check for possible packet drops in the path

- Check if you have any performance issue (high CPU etc) on any end routers

regards

Ashish