Ethernet Switches & Routers

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Occasional Contributor
Posts: 15
Registered: ‎02-21-2011

ARP entries disappear too frequently

Hello All!

I have noticed that some ARP entries disappear from one of my FCX switches in the router mode more frequently than in 10 minutes, which is my (and default) aging time. The example is below (I've underlined two moments when the entry for 192.168.104.70 disappeared). I'm afraid that some of my packets to 192.168.104.70 are dropped or delayed frequently because of this ARP table behavior. In fact I see delays and drops to 192.168.104.70 but I'm not sure that all of them are caused by this strange behavior of the ARP table.

How can I solve this problem if I don't want to add a static ARP entry?

Thank you if you answer.

Example output:

SixSwitchFabric#sh clock
17:40:03 GMT+04 Mon Feb 27 2012
SixSwitchFabric#sh arp 192.168.104.70
No.   IP Address       MAC Address    Type     Age Port           Status
1     192.168.104.70   0015.5d68.0a00 Dynamic  0    5/1/2         Valid
SixSwitchFabric#sh clock
17:40:06 GMT+04 Mon Feb 27 2012
SixSwitchFabric#sh arp 192.168.104.70
No.   IP Address       MAC Address    Type     Age Port           Status
SixSwitchFabric#sh clock
17:40:09 GMT+04 Mon Feb 27 2012
SixSwitchFabric#sh arp 192.168.104.70
No.   IP Address       MAC Address    Type     Age Port           Status
1     192.168.104.70   0015.5d68.0a00 Dynamic  0    5/1/2         Valid
SixSwitchFabric#sh clock
17:40:11 GMT+04 Mon Feb 27 2012
SixSwitchFabric#sh arp 192.168.104.70
No.   IP Address       MAC Address    Type     Age Port           Status
1     192.168.104.70   0015.5d68.0a00 Dynamic  0    5/1/2         Valid
SixSwitchFabric#sh clock
17:40:14 GMT+04 Mon Feb 27 2012
SixSwitchFabric#sh arp 192.168.104.70
No.   IP Address       MAC Address    Type     Age Port           Status
1     192.168.104.70   0015.5d68.0a00 Dynamic  0    5/1/2         Valid
SixSwitchFabric#sh clock
17:40:16 GMT+04 Mon Feb 27 2012
SixSwitchFabric#sh arp 192.168.104.70
No.   IP Address       MAC Address    Type     Age Port           Status
1     192.168.104.70   0015.5d68.0a00 Dynamic  0    5/1/2         Valid
SixSwitchFabric#sh clock
17:40:18 GMT+04 Mon Feb 27 2012
SixSwitchFabric#sh arp 192.168.104.70
No.   IP Address       MAC Address    Type     Age Port           Status
1     192.168.104.70   0015.5d68.0a00 Dynamic  0    5/1/2         Valid
SixSwitchFabric#sh clock
17:40:21 GMT+04 Mon Feb 27 2012
SixSwitchFabric#sh arp 192.168.104.70
No.   IP Address       MAC Address    Type     Age Port           Status
1     192.168.104.70   0015.5d68.0a00 Dynamic  0    5/1/2         Valid
SixSwitchFabric#sh clock
17:40:23 GMT+04 Mon Feb 27 2012
SixSwitchFabric#sh arp 192.168.104.70
No.   IP Address       MAC Address    Type     Age Port           Status
1     192.168.104.70   0015.5d68.0a00 Dynamic  0    5/1/2         Valid
SixSwitchFabric#sh clock
17:40:26 GMT+04 Mon Feb 27 2012
SixSwitchFabric#sh arp 192.168.104.70
No.   IP Address       MAC Address    Type     Age Port           Status
SixSwitchFabric#sh clock
17:40:28 GMT+04 Mon Feb 27 2012

Contributor
Posts: 54
Registered: ‎01-27-2010

Re: ARP entries disappear too frequently

What firmware version on your FCX stack?

Occasional Contributor
Posts: 15
Registered: ‎02-21-2011

Re: ARP entries disappear too frequently

Thank you for your response!

My version is 7202e.

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