WLC 2504 - Slow Internet download speed. Just Internet speed.

[Khoa Pham]

My network is a simple network: 1 Gateway, 1 switch, 1 WLC2504 and 1 AP-3602I

If I wired my laptop to the switch and do speedtest.net, I get 100Mbs down, 100Mbs Up, which is the speed provided by our ISP

If I connect the laptop wirelessly to the AP, and do a Speedtest.net, I get 30-40Mbs down, 100Mbs Up

If I use IPerf to test the connection from the Wireless laptop to a Wired Server, on the same local net, I get 140Mbs Up/Down

At all time, my laptop is connected at 450Mbs, A channel. Only 1 device on the AP, which is my laptop.

You might will ask, but I verified:

- No QoS setup anywhere in the network. WLAN QOS tab is clean.

- I even removed the switch and connected the WLC directly to the gateway. Same results.

Interesting right ? I know.

Please advise.

[rdpierce]

I was having the same issue, wired had 90Mbps down/6Mbps up and wireless was like 18-21Mbps down/5.5Mbps up.

I checked my adapter settings and found that mixed channel mode was enabled by default.  I changed this to the 5.2 MHz channel and now it's running at full speed.

Something to try.

[steve255.0]

So any one find the solution yet? I have the same issue.

[stamperbrian]

Glad I'm not the only one.  Same issue here. Larger deployment. 

5520 on 8.2.161.0 with 30+ sites in Flex Local Switching all using 3802i's.  All sites have a local egress internet ranging from 50Mg to 1gig.  One site in particular is having this same issue.  It has a 250MG circuit.  On the wire we get 200-230 Down/up consistently.  On wireless at this site we get 90-100 down and 200-230Up.  Doesn't matter what cilent.  Examples:

Mackbook Pro: 802.11ac Connected in the -50s and 40s SNR s3 m9 600MG on 40Mhz.  Download 90-100 and upload 200-230 (Expected upload, degraded download).

Lenovos with WIn 10:  802.11 ac Connected in the -50s and 40s SNR s2 m9 400MG on 40Mhz.  Download 90-100 and upload 200-230.  

Any device on the wire gets the right speeds.  

Drive up the road to another site.  Same model AP's, same design/arch, same WLAN's.  Same 250Mg internet.  200-230 down and 200-230 up on wireless. 

The Arch is:

3802i -> 2960XR -> PaloVM -> 250MG Internet

I have 4 WLAN's at this site.  2 are corperate and route locally off the 2960XR and 2 are "guest" type and are layer 2 right into an interface on the Palo.  All have the same issue. I have tried standing up a new FW that was a PFSense and created a whole new layer 2 vlan and WLAN to drop directly to it.  Same issue with that setup.

I have a TAC case open and have linked to this support forum within its notes.  I'll update my findings as I hopefully resolve this. 

[Steve Lattray]

Did you find the cause of your problem? I have a similar issue with slow download speeds. I have 5520WLC - 6509 - 3750G - 2702i. I get 70 up and 6 down. Using iperf test software.

[Steve Lattray]

I found the QOS configuration on the 3750 was part of the problem. After disabling this feature (no MLS QOS) I started getting 17Mbs downloads. Still much slower than expected but better. I also noticed that my Guest SSID (open authentication) is now getting ~60Mbs up and down but my enterprise SSID is only getting 17Mbs downloads. I am using WPA/WPA2 AES with 802.1x. 

WLC = 5520 running 8.2.160.0

AP= 2702i

[stamperbrian]

Working with tac what fixed a bit of my issue was the adjustment of TCP MSS to 1250.  Made a huge difference at a number of sites.  However, I'm still perplexed at one site that gets consistent 100 down 200 up.  Its clearly not "bad" but on the wire its 200/200.   

[Scott Fella]

You can’t compare wired to wireless when it comes to throughout. Wired is full depleted in which wireless is half. TCP MSS we also adjust on sites with VPN connections or low bandwidth links. 100/200 is not bad to be honest.

[stamperbrian]

If it wasn't just this one site that is so odd I wouldn't worry about it.  Just one site that is 100down 200 up.  Most other sites I get closer to the same.  

[Scott Fella]

Test internally with iperf. Connect an iperf server at your core or distro on the same vlan as your wireless. Run iperf from a wireless machine and see what you get. This way you eliminate the L2.

[stamperbrian]

Yup that is the weird thing.  Iperf tests locally look fine.  Symmetrical.  Its only this site on wireless that we see the big degradation in download speed over upload speed.  We will have a second internet connection at some point and I'm going to try flipping to it and testing. 

[CPu]

We are running into the same issue.Slow Internet download, good upload. Good down an upload on local servers.

It's very certain a problem of fragmentation.

We had put a server outside firewall and can reproduce the issue, same here: slow download, good upload.

When reducing the MSS on the outside server download is much better. So definitely a problem of fragmentation.

At the moment I'm not sure whether the firewall or the WLC cause the performance issue when it has to deal with fragmentation.

Environment: WLC 8540, Version 8.6, AP2802

[Steve Lattray]

It looks like our controller is marking the capwap as voice. This is causing the network to drop a good portion of them. I'm going to test with QOS on the controller set to silver or possibly off next week.

[stamperbrian]

Interesting.  I tried playing around with both the QOS and AVC at the site I had issues at and it didn't seem to make a difference. Still just so weird that its just this site....just the internet on wireless.  

[Scott Fella]

We have seen that also and locally everything is fine.  It’s the egress to the provider and a misconfiguation on their end has been an issue. 

[CPu]

You can verify it: Just plug off your provider router and put in an own server. Probably, you will recognise the same issue.