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LDP Neighbor - Holdown / Discovery timer expired.

DuncanM2008
Level 1
Level 1

‎04-04-2012 02:56 AM

Hello,

I'm having an intermittent issue with LDP sessions dropping between one specific router and it's two peers.

Solution background:

We have 3 x 7201 (NPE-G2) running c7200p-spservicesk9-mz.150-1.M5.bin.

The routers are arranged in a "triangle" with a link to each router utilising G0/2 + 3 on each router, IGP is OSPF with all routers + loopbacks being in OSPF Area 0. OSPF RID + MPLS RID is Lo0.

Routers are called ABC-CORE-1, CCC-CORE-1, CBC-CORE1.

During the "outage" the DLP session between ABC->CBC remains constant without issue, however the LDP sessions with CCC-CORE1 both drop stating the following:

ABC-CORE-1#show log

Apr  3 17:30:40.236: %LDP-5-NBRCHG: LDP Neighbor 10.64.255.2:0 (1) is DOWN (Received error notification from peer: Holddown time expired)

Apr  3 17:30:44.180: %LDP-5-NBRCHG: LDP Neighbor 10.64.255.2:0 (1) is UP

CCC-CORE-1#show log

.Apr  3 17:30:39: %LDP-5-NBRCHG: LDP Neighbor 10.64.255.1:0 (1) is DOWN (Discovery Hello Hold Timer expired)

.Apr  3 17:30:43: %LDP-5-NBRCHG: LDP Neighbor 10.64.255.1:0 (3) is UP

Neighbor output:

CCC-CORE-1#sh mpls ldp neigh 10.64.255.1 det

    Peer LDP Ident: 10.64.255.1:0; Local LDP Ident 10.64.255.2:0

        TCP connection: 10.64.255.1.646 - 10.64.255.2.36718

        Password: not required, none, in use

        State: Oper; Msgs sent/rcvd: 1191/1192; Downstream; Last TIB rev sent 130

        Up time: 16:24:42; UID: 10; Peer Id 2;

        LDP discovery sources:

          GigabitEthernet0/2; Src IP addr: 10.64.0.1

            holdtime: 15000 ms, hello interval: 5000 ms

        Addresses bound to peer LDP Ident:

          10.64.2.1       192.168.128.126 10.64.0.1       10.64.0.5

          10.64.255.1     10.64.254.1

        Peer holdtime: 180000 ms; KA interval: 60000 ms; Peer state: estab

        Clients: Dir Adj Client

        Capabilities Sent:

          [Dynamic Announcement (0x0506)]

          [Typed Wildcard (0x0970)]

        Capabilities Received:

          [Dynamic Announcement (0x0506)]

          [Typed Wildcard (0x0970)]

ABC-CORE-1#show mpls ldp neigh 10.64.255.2 det

    Peer LDP Ident: 10.64.255.2:0; Local LDP Ident 10.64.255.1:0

        TCP connection: 10.64.255.2.36718 - 10.64.255.1.646

        Password: not required, none, in use

        State: Oper; Msgs sent/rcvd: 1193/1191; Downstream; Last TIB rev sent 130

        Up time: 16:25:05; UID: 8; Peer Id 0;

        LDP discovery sources:

          GigabitEthernet0/2; Src IP addr: 10.64.0.2

            holdtime: 15000 ms, hello interval: 5000 ms

        Addresses bound to peer LDP Ident:

          10.64.2.5       192.168.128.254 10.64.0.2       10.64.0.9

          10.64.255.2     10.64.254.2

        Peer holdtime: 180000 ms; KA interval: 60000 ms; Peer state: estab

        Clients: Dir Adj Client

        Capabilities Sent:

          [Dynamic Announcement (0x0506)]

          [Typed Wildcard (0x0970)]

        Capabilities Received:

          [Dynamic Announcement (0x0506)]

          [Typed Wildcard (0x0970)]

I've just enabled MPLS IGP sync this morning aftere reading a few articles however I'm not convicnced that's going to make much difference, has anyone ever experieced this before?

Thanks,

Duncan.

3 people had this problem
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2 Replies 2

DuncanM2008
Level 1
Level 1

‎04-11-2012 04:59 AM 

Duncan Mossop wrote:
Hello,
I'm having an intermittent issue with LDP sessions dropping between one specific router and it's two peers.
Solution background:
We have 3 x 7201 (NPE-G2) running c7200p-spservicesk9-mz.150-1.M5.bin.
The routers are arranged in a "triangle" with a link to each router utilising G0/2 + 3 on each router, IGP is OSPF with all routers + loopbacks being in OSPF Area 0. OSPF RID + MPLS RID is Lo0.
Routers are called ABC-CORE-1, CCC-CORE-1, CBC-CORE1.
During the "outage" the DLP session between ABC->CBC remains constant without issue, however the LDP sessions with CCC-CORE1 both drop stating the following:
ABC-CORE-1#show log
Apr  3 17:30:40.236: %LDP-5-NBRCHG: LDP Neighbor 10.64.255.2:0 (1) is DOWN (Received error notification from peer: Holddown time expired)
Apr  3 17:30:44.180: %LDP-5-NBRCHG: LDP Neighbor 10.64.255.2:0 (1) is UP
CCC-CORE-1#show log
.Apr  3 17:30:39: %LDP-5-NBRCHG: LDP Neighbor 10.64.255.1:0 (1) is DOWN (Discovery Hello Hold Timer expired)
.Apr  3 17:30:43: %LDP-5-NBRCHG: LDP Neighbor 10.64.255.1:0 (3) is UP
Neighbor output:
CCC-CORE-1#sh mpls ldp neigh 10.64.255.1 det
    Peer LDP Ident: 10.64.255.1:0; Local LDP Ident 10.64.255.2:0
        TCP connection: 10.64.255.1.646 - 10.64.255.2.36718
        Password: not required, none, in use
        State: Oper; Msgs sent/rcvd: 1191/1192; Downstream; Last TIB rev sent 130
        Up time: 16:24:42; UID: 10; Peer Id 2;
        LDP discovery sources:
          GigabitEthernet0/2; Src IP addr: 10.64.0.1
            holdtime: 15000 ms, hello interval: 5000 ms
        Addresses bound to peer LDP Ident:
          10.64.2.1       192.168.128.126 10.64.0.1       10.64.0.5
          10.64.255.1     10.64.254.1
        Peer holdtime: 180000 ms; KA interval: 60000 ms; Peer state: estab
        Clients: Dir Adj Client
        Capabilities Sent:
          [Dynamic Announcement (0x0506)]
          [Typed Wildcard (0x0970)]
        Capabilities Received:
          [Dynamic Announcement (0x0506)]
          [Typed Wildcard (0x0970)]
ABC-CORE-1#show mpls ldp neigh 10.64.255.2 det
    Peer LDP Ident: 10.64.255.2:0; Local LDP Ident 10.64.255.1:0
        TCP connection: 10.64.255.2.36718 - 10.64.255.1.646
        Password: not required, none, in use
        State: Oper; Msgs sent/rcvd: 1193/1191; Downstream; Last TIB rev sent 130
        Up time: 16:25:05; UID: 8; Peer Id 0;
        LDP discovery sources:
          GigabitEthernet0/2; Src IP addr: 10.64.0.2
            holdtime: 15000 ms, hello interval: 5000 ms
        Addresses bound to peer LDP Ident:
          10.64.2.5       192.168.128.254 10.64.0.2       10.64.0.9
          10.64.255.2     10.64.254.2
        Peer holdtime: 180000 ms; KA interval: 60000 ms; Peer state: estab
        Clients: Dir Adj Client
        Capabilities Sent:
          [Dynamic Announcement (0x0506)]
          [Typed Wildcard (0x0970)]
        Capabilities Received:
          [Dynamic Announcement (0x0506)]
          [Typed Wildcard (0x0970)]
I've just enabled MPLS IGP sync this morning aftere reading a few articles however I'm not convicnced that's going to make much difference, has anyone ever experieced this before?
Thanks,
Duncan.

For anyone that's interested I fixed this problem after some in depth troubleshooting.

Turns out the CCC router has CEF disabled.

I followed the through the following process:

Noticed flushes in the inteface counters -> researched SPD (selective packet discard) -> looked into CPU usage -> noticed IP Input process running 90%+, checked CEF with "show ip cef" showed a full adjancency table.

Checked the command "show cef interface"

Boom, "CEF Switching disabled" on every interface.

"no ip cef" "ip cef" , fixed.

For reference the running config did indeed show "ip cef" as entered and turned on.

Only thing I can think is when we upgraded from 12.4 to 15.0(1)M there was a glitch with CEF....

Very strange.

0 Helpful

evergreenajay
Level 1
Level 1

‎04-12-2012 05:44 AM

Tht's great..I have just started reading the mpls..your question will help me to enhance my skills..thanks for ur question and ans too..I really some help of u..pls reach me at ajaysartaj@gmail.com

Sent from Cisco Technical Support iPhone App

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