01-08-2014 11:53 PM
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
01-09-2014 05:34 PM
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
01-10-2014 12:38 AM
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
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