ZD 1100 and 7373 APs: Very slow throughput

[john_lotz_68378]

I have a zone director 1106 (running 9.8.1.0 build 101) connected to 3 7363 APs and have very low throughput over the wireless network. This is both for internet traffic on TimeWarner Business Class with 200mpbs down and 20mpbs up and over the local network. Wired transfers over the local network are 112-115MBps. Wireless speeds are in the kilobytes. Anything but the most basic internet browsing is maddeningly slow.

I reset the ZD to defaults to start over and have the same problem. I have a support case open in which we spent a few hours on the phone troubleshooting and support is now looking at logs and such. Support created a test WLAN on one AP and made a few changes to that WLAN that got some increase in speed but not much and certainly not anywhere near wired speeds. IIRC, we might have seen 6MBps on this test WLAN.

While I'm patiently waiting for support's response, I'm hoping the community might have some thoughts or suggestions on what to try or look at. I know Ruckus is supposed to just work but, well, it doesn't. Thanks in advance!

[john_d]

This part pretty key... You're using 7372's which are 2x2:2 N with peak rates of 300mbit. Except on 2.4GHz you are often limited to 20MHz channels, which cuts your observed throughputs in about half. Those values are airtime capacities too -- observed throughputs are at about 50% of theoretical capacity on wifi, even less with 802.11ac.

8-9MB/s is 64-72mbit/s, which is pretty good throughput for 802.11n. 6MB/s (40-50mbit/s) is not too bad on 2.4GHz either, especially in a RF polluted environment.

If you want something slightly faster, a 3x3:3 paired with 3 stream clients (such as laptops/desktops) will bring you close to 100-125mbit observed throughputs.

[hayward_kong]

You might also need to hire a local IT Wifi Consultant to see what's happening at your site. What all boils down to is to do a Wifi site survey and understand the results.

[kristijan_fabin]

John,

if speeds are constantly in kilobytes on both 2.4 and 5 GHz, then something is seriously wrong. Too many non-overlapping channels on 5 GHz, I doubt they are all in shitty environment.

for 2.4 GHz fluctuations are normal especially if you have a lot of active networks on the same and near channels. Force your clients to 5 GHz.

If you have ZoneDirector, go to Configure > Services and go to Band Balancing. which balances the load on Radios, by distributing the clients on 2.4GHz and 5GHz radios.

Percent of clients on 2.4GHz radio 5% (that could help)

[john_lotz_68378]

Thank you all for the replies.

Working with support, we narrowed the problem to 2.4ghz and enabled channelfly which did not resolve the problem. I now believe that I have non-wifi 2.4ghz interference that kills wifi performance. Note that I understand MBps vs Mbps and never expected wireline performance over wireless. However, the throughput numbers were the only objective way to measure "my wifi sucks". It's really bad.

I've thought about getting spectrum analysis tools (I'm an IT person but lack the right tools for this issue) but doubt I'll be able to do anything about the interference that I find. It is what it is and I need to work around it.

I've tried narrowing clients to 5ghz but 5ghz range is not good, I'd have to dramatically increase the number of APs.

I'm considering getting different APs but am trying to figure out if the R700, for example, will be better able to work around all the interference on 2.4. Is that part of the improved feature set for the higher-end APs or will I generally have the same problems?

[john_d]

Hi John,

So I've got both an R700, a bunch of 7982's, and a 7372, and there definitely is a range and SLIGHT throughput (25% better range, maybe 10% better throughput) improvement on 2.4, but I doubt it's enough to be a value proposition to you. You are almost certainly better off just putting in more access points and the 7372 (or new R500) is a very cost effective solution to that compared to R700.

Especially considering your 5GHz range is inadequate for your clients, that leads me to infer that you've got your AP's spaced far apart, so there's zones where interference can easily overpower your AP's on 2.4. 2.4 goes really far with great bandwidth in a clean environment, but in a noisy environment it doesn't go all that much farther than 5GHz while still being able to cut through interference.

The higher end AP's give you a few more dB's of interference mitigation, but if your dilemma is between the same number of R700's or doubling the number of 7372's (which is pretty much the same cost), I'd say the second option wins.

(Note that the R700's and 7982's are quite awesome especially for super high density environments, or places where you simply have a zone where it's not practical to run access points such as a college dorm where hallway AP's need to punch into dorm rooms as far as possible)