port-security aging time to low?

Unanswered Question
Oct 22nd, 2008

We are gearing up to implement port security in our environment and we are considering an aging type of inactivity and an aging time of 2 minutes. This is to allow for PC and other equipment changes without requiring manual intervention.

Is there an aging time (other than 0) that would negatively affect switch performance? As I indicated above, we are currently considering two mintues. How about 2 seconds? Is this something to be concerned about?

I have this problem too.
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Giuseppe Larosa Wed, 10/22/2008 - 23:30

Hello Morgan,

if you set an aging time of type inactvity for 2 seconds you get:

a useless port security configuration everyone can come and plug its laptop into the port without a chance to be blocked

I would worry also about CPU usage: there should be a process that checks MAC addresses on all secured ports : setting a 2 seconds aging time will likely increase the frequency of this check and so this could lead to a bigger CPU load.

You can address this issue by informing tech people to wait 2 minutes before plugging in the new device: cables changes shouldn't happen very often.

If instead the scenario is with many changes you could consider the usage of 802.1X authentication.

Hope to help



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