Introduction
WLC update from 7.6.120.0 to 8.0.110.0 - speed and ms drops alot.
Core Issue
User had to update their Wism2's and 5508's to 7.6.120.0 for 3702 support. One of the Wism2's started to hand/restart a few times per week after the update. Other than that the wireless was working good. TAC found some bugs that suited what they could read from the logs and told me to update to 8.
So user upgrade, and *smack* the wireless dropped to speeds around 5-10 Mbits with 80+ ms. Yielding that exchange, fileservers and alot if not all programs did not function/lost connection.
Solution
After the upgrade the upgrade. The upgrade itself had enabled interim update under the AAA accounting with a value of 0. I tried on our lab controller to turn on interim with the same value but the system wouldn't let me since its not an accepted value. So I turned the function off on one of the live controllers (that just had a few AP's heh) and immediately the Wireless were back delivering good speeds and answering times again.
Another user did confirmed that 8.x upgrade automatically enabled interim update with 0 value and disabled them manually after seeing this.
Similar Issue
This bug might be connected to the problem https://supportforums.cisco.com/discussion/11894006/ise-12-wlc-5508-nas-sends-radius-accounting-update-messages-too-frequently
More Information
Description - WLC sends acct-update twice in the same millisecond - CSCug14713
Symptom:
Radius Accounting update seen twice from the WLC when initial authentication occurs for Radius NAC enabled WLAN.
Conditions:
When Radius NAC is enabled.
Workaround:
No Workaround.