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OSPF Exstart - After Router Rebooted

tckoon
Level 1
Level 1

Hi,

Two router connected via GE links, OSPF point-to-point. Both router form OSPF neighbor in full state and runnning for years.

Last week one of the router get reboot...after rebooted the OSPF adj cannot up and stuck in EXSTAT state.

Debug do not see any problem with MTU setting...etc..etc... it just problem after one of router rebooted.

After I did this workaround and it work again :

1) remove the interface MTU setting ( previously set to 1600)

2) add the MTU setting back to interface again.

then the OSPF adj is up and running.

ANyone can tell what is the problem..it is the bug ?

Regards

2 Replies 2

andrew.prince
Level 10
Level 10

The MTU on both sides of the link must match when the OSPF neighbour starts to form, if they mis-match the neighbor will not form.

See the below explaination:-

http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a0080093f0d.shtml

HTH>

Giuseppe Larosa
Hall of Fame
Hall of Fame

Hello Choh,

it looks like the router was not able to apply the startup config mtu command.

This looks like a possible bug but to narrow a possible search the ios image and platform could help.

Or search by yourself with MTU as keyword in the Bug toolkit

Hope to help

Giuseppe

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