OSPF neighbor discover fails when connected to Cisco

Asset ID:	1-72-1600266.1
Update Date:	2016-10-26
Keywords:

Solution Type Problem Resolution Sure

Solution 1600266.1 : OSPF neighbor discover fails when connected to Cisco

Applies to:

Sun Blade 6000 10GbE Switched 24p NEM - Version Not Applicable to Not Applicable [Release NA]
Sun Network Switch - Version All Versions to All Versions [Release All Releases]
Information in this document applies to any platform.

Symptoms

OSPF neighbor discovery failes when connected to Cisco switch.

SEFOS# show ip ospf neighbor

Vrf default
Neighbor-ID Pri   State              DeadTime   Address           Interface
----------- ---   -----              --------   -------           ---------
12.0.0.1     1     INIT/PTOP        31         10.196.20.1       vlan20

State should show FULL/PTOP.

Cause

Sun 10Gb ethernet switches (72p, E1s-24, 24pNEM) have a default MTU of 9000 and Cisco has a default mtu of 1500.

Solution

Match the MTU on both sides of the link, i.e. set Sun Ethernet Switch to 1500, OR set Cisco MTU to 9000.

To configure MTU on the Sun Ethernet Switch, use the following commands:

SEFOS# config t
SEFOS(config)# interface extreme-ethernet 0/10
SEFOS(config-if)# shut
SEFOS(config-if)# mtu 1500
SEFOS(config-if)# no shut
SEFOS(config-if)# end
SEFOS# write startup-config

Now, confirm OSPF is working and state should move from INIT to FULL.

SEFOS# show ip ospf neighbor

Vrf default
Neighbor-ID Pri   State              DeadTime   Address           Interface
----------- ---   -----            --------   -------         ---------
12.0.0.1     1     FULL/PTOP          31         10.196.20.1       vlan20

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