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New Member

swap of a computer with anothe one with same IP on same cisco port

Hello,

Then i loose ip connectivity forl ong time ( about 5mn....)

Do you know a command on Catalyst 2948 wich permit to refresh rapidly the cam/arp table and then to recover the ip connectivity????

Thanks and regards

Jerome

5 REPLIES
New Member

Re: swap of a computer with anothe one with same IP on same cisc

Well "clear arp-cache" will clear the cache imediatelly. But you have to write it everytime manual.

New Member

Re: swap of a computer with anothe one with same IP on same cisc

First thanks a lot for your quick answer.

This command doesn't exist on catalyst 2948g.... But i try the command "clear cam dyn 10" (I used vlan 10 for my switch....). But i still have the same problem.... The arp entrie are cleaned, but then it doesn't refresh quickly the table... So i loose ip connectivity for a long time. Is there a command to refresh this table???

Thanks and regards

Jerome

Cisco Employee

Re: swap of a computer with anothe one with same IP on same cisc

Default CAM aging time is 300 seconds and you can change it to whatvever you want per VLAN using "set cam agingtime [vlan] x"

http://cio.cisco.com/univercd/cc/td/doc/product/lan/cat4000/rel6_3/cmd_ref/set_a_d.htm#13648

My suggestion to you would be troubleshoot why the switch does not learn the MAC address. If the MAC address is of a end machine like a PC, printer/server, enable "set port host x/y" on the port

New Member

Re: swap of a computer with anothe one with same IP on same cisc

MAC address should dissappear when the device is removed from the layer 2 port. I would suspect the spanning tree is holding the port from forwarding traffic. Enable span portfast option.

kevin

New Member

Re: swap of a computer with anothe one with same IP on same cisc

Hi,

The issue that you are seeing may not be related to the switch CAM table but the arp entry in the device that you are trying to connect to.

Try clearing the MAC table of the device you are trying to connect to or the network gateways (router) MAC table, if device you are connection to is in another IP network.

Hope this helps !

Regards

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