Hi everyone,
Fairly recently, our school district completed a replacement of our older controller-based AP-65s and 105s with all IAPs. We have 40 sites, each of which has its own subnet and, therefore, its own IAP cluster. Each site has an IAP-225 as the preferred master for the VC. Some sites are all IAP-225s, but most are a mixture of a few IAP-225s and mostly IAP-205s. The largest deployment has 142 IAPs, the second largest is 126, and the rest are all 100 or fewer.
Over the past month or so, we have started noticing 2 major issues, both with the IAP-205s:
1) After a few days of uptime, random IAP-205s throughout the district will stop handling DHCP requests properly. We saw during a Wireshark packet capture that during the DHCP handshake process, the Discover packet went out, Offer came back, Request went out, but the ACK never came back from the client. I don't know if that means the Offer made it to the AP and then never made it to the client, or if the Offer made it to the client but then the ACK never made it back to the AP. But this particular problem has become rather epidemic, resulting in having to reboot entire IAP clusters on a weekly basis. I've had a TAC case open on this for a few weeks, but we're not making much progress. When this happens, I've been noticing that the IAPs in question have very little free memory as reported by the VC (like 4 MB or less), whereas they usually have about 30 or 40 MB free.
2) This happens less often, but sometimes, the CPU utilization on random IAP-205s gets pegged at 100%. I just opened a TAC case on this as well. When it happened today, I SSH'd into the IAP in question and did a "show cpu details", and a process called "dpimgr" was consuming 98% of the CPU. I also did a "show tech-support" to send to TAC, but it took me a couple of tries because the IAP kept closing my SSH connection.
I'm starting to think the IAP-205s weren't designed well, i.e. perhaps they have too little memory and/or not enough CPU power, to be able to function well in a dense deployment. Has anyone else had any experiences like this? We've had no problems whatsoever with the IAP-225s. I'm now wishing we had gone with ALL IAP-225s, but of course, that would have cost 3 times as much.
Thanks!
#AP225