It seems that everyone I talk to has wireless challenges in their environment and network. I recently deployed ~ 60 Cisco 3702e Access Points paired with a set of Cisco 5508 Wireless LAN Controllers running software release 7.6.100 in a newly renovated building. I wasn’t anticipating any issues or problems but you can guess what I ended up stumbling upon. While we thought everything was working fine we quickly discovered that 5Ghz clients were having severe performance and connectivity issues. I could run continuous ICMP pings but the moment I put the client under load I would either loose connectivity or experience severe packet loss upwards of 80-90%. We had the same results from a Lenovo T420 and T430 laptop and a MacBook Air.

We opened a case with Cisco TAC and discovered that we were experiencing a known issue;

• CSCuj17283 – Cisco AP3700 used 8 replay counters with clients that support only one (ARP failed).

The bug above is resolved in software release 7.6.110, here are the release notes. We’re currently testing software release 7.6.110 although Cisco has just released 7.6.120 – release notes.

If your going to be deploying the Cisco 3700 Access Points you’ll want to make sure that your WLC is running a minimum software release of 7.6.110.

Cheers!