%OSPF-5-ADJCHG: Process 1800, Nbr 172.20.102.147 on GigabitEthernet0/2.121 from FULL to DOWN, Neighbor Down: Dead timer expired

[gerson-soares]

I have a network infrastructure with Cisco 6500 and Cisco 7200.

The network run OSPF between all networks of all sites (WAN, MAN)
This network stoped by 6 minutes and after that time came back.
In the log we have the mensagens ;

Messages in log of Cisco 6500;

Jul 29 11:58:13.487 BRT: %OSPF-5-ADJCHG: Process 1092, Nbr 172.20.5.39 on Vlan1092 from FULL to DOWN, Neighbor Down: Dead timer expired
Jul 29 11:58:13.495 BRT: %OSPF-5-ADJCHG: Process 1500, Nbr 172.20.5.83 on Vlan1501 from FULL to DOWN, Neighbor Down: Dead timer expired
 

Messages in log of Cisco 7200

Jul 29 2015 11:58:42.370: %OSPF-5-ADJCHG: Process 1030, Nbr 172.20.104.20 on GigabitEthernet0/2.1615 from FULL to DOWN, Neighbor Down: Dead timer expired
Jul 29 2015 11:58:42.370: %OSPF-5-ADJCHG: Process 1030, Nbr 172.20.5.20 on Port-channel1.1030 from 2WAY to DOWN, Neighbor Down: Dead timer expired
Jul 29 2015 11:58:42.370: %OSPF-5-ADJCHG: Process 1030, Nbr 172.20.104.19 on GigabitEthernet0/2.1615 from FULL to DOWN, Neighbor Down: Dead timer expired
Jul 29 2015 11:58:42.374: %OSPF-5-ADJCHG: Process 1030, Nbr 172.20.5.54 on Port-channel1.1030 from FULL to DOWN, Neighbor Down: Dead timer expired

Please i need help.

[Martin Hruby]

From the log output it's clear that the OSPF adjancies went down. There can be many causes for this, such as underlying VLAN issues, STP, link failure, network congestion, resource exhaustion, etc.

Please provide your configuration of OSPF and ideally a diagram detailing the OSPF topology

Best regards,
Martin

[gerson-soares]

Hello Martin and Joseph, thank you.

I am sending information of OSPF topology and network topology;

I put two files that i think help us see de configuration

Gerson Soares

[Joseph W. Doherty]

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Posting

Dead timer expiration would indicate no OSPF hello keepalives were received during the dead timer interval.  As Martin describes, there can be many causes.  When you identify the cause, you then either remediate the issue or you adjust OSPF to be more "robust" dealing with the cause of the issue.  The latter might include increasing the number of hellos during a dead interval and/or increasing the dead interval timer.