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David Serarols
Beginner

OSPF neighbors down and up only en Catalyst 3650

Hello everybody,

 

We have a very strange issue in a Catalyst OSPF network. In this network we have 3560, 3750 and some 3650.

Until now, network without 3650 worked fine, but with new 3650 these log appeared:

 

Mar 16 21:52:03.994 CET: %OSPF-5-ADJCHG: Process 1, Nbr 192.168.254.43 on GigabitEthernet1/1/3 from FULL to DOWN, Neighbor Down: Dead timer expired
Mar 16 21:52:04.073 CET: %OSPF-5-ADJCHG: Process 1, Nbr 192.168.254.52 on GigabitEthernet1/1/2 from FULL to DOWN, Neighbor Down: Dead timer expired
Mar 16 21:52:04.142 CET: %OSPF-5-ADJCHG: Process 1, Nbr 192.168.254.53 on GigabitEthernet1/1/1 from FULL to DOWN, Neighbor Down: Dead timer expired
Mar 16 21:52:04.915 CET: %OSPF-5-ADJCHG: Process 1, Nbr 192.168.254.43 on GigabitEthernet1/1/3 from LOADING to FULL, Loading Done
Mar 16 21:52:04.915 CET: %OSPF-5-ADJCHG: Process 1, Nbr 192.168.254.52 on GigabitEthernet1/1/2 from LOADING to FULL, Loading Done
Mar 16 21:52:04.915 CET: %OSPF-5-ADJCHG: Process 1, Nbr 192.168.254.53 on GigabitEthernet1/1/1 from LOADING to FULL, Loading Done

This log appeared only related to 3650, and never in 3750 or 3560.

We verifyed MTU is the same in all Catalyst (1500).

I attach an extract of interface configuration:

interface GigabitEthernet1/2
 description L3 link AES-4.2 Ge0/2
 no switchport
 dampening
 ip address 192.168.252.218 255.255.255.252
 no ip redirects
 no ip unreachables
 no ip proxy-arp
 ip pim query-interval 10
 ip pim sparse-mode
 ip ospf authentication message-digest
 ip ospf message-digest-key 1 md5 7 ***supressed
 ip ospf network point-to-point
 ip ospf dead-interval minimal hello-multiplier 4
 carrier-delay msec 0
 srr-queue bandwidth share 1 70 25 5
 priority-queue out 
 mls qos trust dscp
!

 

interface GigabitEthernet0/2
 description L3 link AES-4.1 Ge1/2
 no switchport
 dampening
 ip address 192.168.252.217 255.255.255.252
 no ip redirects
 no ip unreachables
 no ip proxy-arp
 ip pim query-interval 10
 ip pim sparse-mode
 ip ospf authentication message-digest
 ip ospf message-digest-key 1 md5 7 ***supressed
 ip ospf network point-to-point
 ip ospf dead-interval minimal hello-multiplier 4
 carrier-delay msec 0
 srr-queue bandwidth share 1 70 25 5
 priority-queue out 
 mls qos trust dscp
!

3650 runs IOS XE and some commands are different and I am not familiar with. 

Anyone knows? Thank you in advance.

David

 

 

 

9 REPLIES 9
Cisco Freak
Enthusiast

Hi David,

How frequent the OSPF neighborship is tearing down? Did it happen one time only or repeated?

CF

Hi,

It happens twice or three times per day.

 

Regards,

David

Did you check the CPU load on the device. Please share the below outputs:

sh processes cpu history

sh logging

sh processes cpu sorted | ex 0.00

sh memory

CF

 

Thank you very much for your comments.

In fact, switches are not still in production, so traffic amount or CPU would not be a problem.

I carry on investigating and I will post what I find.

Regards,

David

 

I experienced the exact same problem a couple of years ago with 3750x. OSPF neigborships flapping, it was due to CPU hitting maximum. Further investigation we found it was multicast traffic (some reasonable volumes) i changed the code to 12.2(55) it did improve. In the end this site expanded and put in C6K's and never saw that problem again.

Please rate useful posts & remember to mark any solved questions as answered. Thank you.

Hi David,

I am having the same issue. Did you get this resolved?

Thanks

Martin

Hi Martin,

Sorry for not having updated my question. Fortunately we solved this issue.

Have you a fast hello command in the interface configuration?

ip pim query-interval 10
ip pim sparse-mode
ip ospf authentication message-digest
ip ospf message-digest-key 1 md5 7 xxxxxxxxxxxxxxxxxxxxx
ip ospf network point-to-point
ip ospf dead-interval minimal hello-multiplier 4

We discovered in these IOS you can not use "ip ospf dead-interval minimal hello-multiplier 4". Please, try without this command and tell us.

Regards,

David

Hello.

Just for anybody looking to the thread for resolution.

OSPF fast-hellos (sub-second) feature is not supported on 3650/3750[X]/3850 platforms (effective date Jan 2017).

The best timers are 1/3, that even may be affected by CSCuz98375.

CSCuz98375 first will be fixed in 3.7.5E

 

Please also note CSCvc44763 - first fixed in 3.6.7.

May not be available in 3.7.6 (due to EOL note).

Looks like Polaris (16.3.x and 16.6.x) is not affected.

removed