[c-nsp] ospf neighbor flap

[Riccardo Tortorici]

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On Oct 27, 2006, at 6:58 AM, Dale W. Carder wrote:

> If you do "sh proc cpu history" when it happens, do you
> see high cpu usage?
>
> Also, what software version are you running.
>
> Dale

Hi,
show proc cpu history does not show any kind of problem.
I ran "debug ip ospf hello" and as far as I can see I receive hello  
packets with a lot of delay (the output parsed follows):

[...]
Oct 26 15:45:29 NFT: OSPF: Rcv hello from 10.63.16.69 area 0 from  
Vlan909 10.63.16.69
Oct 26 15:45:37 NFT: OSPF: Rcv hello from 10.63.16.69 area 0 from  
Vlan909 10.63.16.69
Oct 26 15:45:38 NFT: OSPF: Rcv hello from 10.63.16.69 area 0 from  
Vlan909 10.63.16.69
Oct 26 15:45:44 NFT: OSPF: Rcv hello from 10.63.16.69 area 0 from  
Vlan909 10.63.16.69
Oct 26 15:45:47 NFT: OSPF: Rcv hello from 10.63.16.69 area 0 from  
Vlan909 10.63.16.69
Oct 26 15:45:57 NFT: OSPF: Rcv hello from 10.63.16.69 area 0 from  
Vlan909 10.63.16.69
Oct 26 15:46:02 NFT: OSPF: Rcv hello from 10.63.16.69 area 0 from  
Vlan909 10.63.16.69
Oct 26 15:46:04 NFT: OSPF: Rcv hello from 10.63.16.69 area 0 from  
Vlan909 10.63.16.69
Oct 26 15:46:05 NFT: OSPF: Rcv hello from 10.63.16.69 area 0 from  
Vlan909 10.63.16.69
[...]

let's try to summary the architecture as:
	
             			MY7606
                    			|
		   			|
  	 Multilayer Switch (only L2 for vlan 909)
			|					|
			|					|
     Juniper (10.63.16.69)    Juniper (10.63.16.66)

By the way.. I use 12.2(18)SXD6 with sup2
Bye,
Ric

>
> On Oct 26, 2006, at 10:31 AM, Riccardo Tortorici wrote:
>
>> Hi guys,
>> I'm experiencing a strange problem on ospf.
>> I have one 7609 acting as border router in area0, on the same vlan
>> there are other routers (juniper, out of my control) running ospf.
>> I don't notice any connectivity problem with my neighbors, I did a
>> flooding ping for 10 minutes and I miss no packets.
>> I previously had the default dead timer on interface command and  "ip
>> ospf hello-interval 2" but I noticed I receive *all* the neighbors
>> hello packets after 8-10 seconds, so I decided to increase the dead
>> time to 16 as workaround.
>> Right now the neighbors flap less often but sometimes it happens.
>> I double-checked vlan and interfaces counters to see errors but  
>> nothing.
>> Is there someone that already faced this issue?
>> Regards,
>> Riccardo
>>
>> interface Vlan909
>> description XXX
>> ip address 10.63.16.68 255.255.255.240
>> no ip redirects
>> ip ospf hello-interval 2
>> ip ospf dead-interval 18
>> end
>> !
>> router ospf 100
>> router-id 10.63.16.68
>> log-adjacency-changes
>> redistribute connected metric 20 subnets
>> redistribute static metric 20 subnets
>> network 10.63.16.64 0.0.0.15 area 0
>> default-information originate always metric 20
>>
>>
>> #sho ip ospf neighbor
>>
>> Neighbor ID     Pri   State           Dead Time   Address
>> Interface
>> 10.63.16.66     128   FULL/DR         00:00:01    10.63.16.66
>> Vlan909
>> 10.63.16.69     128   FULL/BDR        00:00:05    10.63.16.69
>> Vlan909
>>
>>
>>
>> - Riccardo Tortorici -
>> Linux Registered User #365170
>> Count yourself @ http://counter.li.org/ !
>> --
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>> F3FC E306
>>
>>
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>
>
> ---------------------------------------------------------------------- 
> --
> Dale W. Carder - Network Engineer   | DoIT Network Services
> University of Wisconsin at Madison  | dwcarder at doit.wisc.edu
> (608) 263-3628 | 24hr NOC: 263-4188 | http://net.doit.wisc.edu/ 
> ~dwcarder
>
>

- - Riccardo Tortorici -
Linux Registered User #365170
Count yourself @ http://counter.li.org/ !
- --
Encrypted Mails Welcome
GPG key: 0xF3FCE306 available on  wwwkeys.pgp.net
GPG key fingerprint = C1C4 CA17 5135 8F5C 94C2  3347 4A22 67DB F3FC E306


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