Friday, August 13, 2021

Session Timeout and DHCP Address Required on Cisco Wireless?

I've recently implemented new SSIDs on our campus, including in our residence halls, with some different security setups through ISE. As part of the new SSID creation, I left a number of settings at their defaults to start with, including the session timeout at 30 minutes. One setting I did not leave at default was the DHCP Address Assignment requirement. I turned this on in order to try to prohibit people from setting up static IPs on their devices (we have seen this occur on occasion in the past).

After setup, I read somewhere that turning on the DHCP required option isn't really considered best practice and can cause various issues.

We've had a few reports of game consoles and such in the residence halls losing connectivity during multiplayer games and that, when they time it, it does seem to be consistent to that 30 minute mark. On the other hand, my understanding as I've been learning ISE is that there are several good reasons to keep a lower session time like the default 30 minutes instead of raising it too much or disabling it completely (which is what we used to do).

I'm wondering if the session time itself is probably the issue or if it is a combination of that with the DHCP requirement.. for example, is the WLC forcing an entire DHCP transaction to occur between the client and the DHCP server which causes a delay in wireless session renewal.

I'm curious what others in this space are doing for these types of settings, particularly with residence halls?

Thanks!



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