3702i slow download speeds

[CourtneyKPrin]

WLC 5508 environment with many 3702i and 3802i APs. There is one 3702i that slows a client's download speeds and the upload speeds appear normal. With one to two devices connected to the AP, the iperf download speeds are around 20 Mb/s (using -R). The iperf upload speeds are around 125 Mb/s. I replaced the problem AP with a spare 3702i and the client's download speeds are around 100 Mb/s (using -R). With the problem AP on the bench, I have done the format flash and recovery image process with no difference (~20 Mb/s using iperf -R). The clients are connecting with 5Ghz channels. Any thoughts on what would cause this? Would the AP complain if an internal antenna was malfunctioning?

[CourtneyKPrin]

Correct, the problem 3702i APs are being rebooted at my desk and have the same issue.

I found another one today that has slow download speeds and is a 3802i. This one is covered by TAC and I submitted a case. I replaced it with a repurposed 3702i (running out of those!) and brought the problem 3802i back to my desk. I did a factory reset via the WLC and still see slow download speeds (<10Mb/s) using iperf with -R.

FYI, the users connected to the replaced APs are not having issues today and reported normal download speeds.

[Leo Laohoo]

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@CourtneyKPrin wrote:

This one is covered by TAC and I submitted a case.

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All 3700 are covered under Limited Lifetime Hardware Warranty.  There is no need to put those AP in a Service Contract.

[CourtneyKPrin]

I explained to Cisco support that I replaced a problem AP with repurposed AP, same cabling, switch, and switch port, and the download speeds are above 100Mb/s. They asked for WLC config and log files and replied last night that it is bad hardware and asked for my shipping address. My concern is, I have now found 8 APs with the same symptoms and I don't think it's an AP hardware issue. I took the advice of someone here to try a problem AP in Autonomous Mode and I converted a 3802i into MobilityExpress. The iperf -R download speeds are at 137Mb/s.

[CourtneyKPrin]

I converted the problem 3802i AP back to CAPWAP, shutdown a known good AP, used its IP on the problem 3802i, and download speeds are near 100Mb/s. I now think it's related to the etherchannel between the switch and the WLC. The etherchannel load-balance on the switch is configured with src-dst-ip and there are 8 members to the etherchannel. Any thoughts on how to verify the etherchannel is working properly on the WLC?

[CourtneyKPrin]

We are using two 5508 in pair mode and I forced a failover to test the 8 port member etherchannel. I thought if the symptoms follow then it's not the etherchannel or the WLC hardware. The problem APs are still below 20Mb/s and the replacement APs are near 100Mb/s. Now what?!

[CourtneyKPrin]

Follow-up... Still thinking it's a load balancing issue and identifying traffic between two switches is using OSPF over a bundled trunk, I forced the routed traffic to VLAN 3 using 'passive-interface vlan 1'. Since then the download speeds are normal for all APs. So, something on VLAN 1 is causing the slow traffic.