unable to solve wifi issues...please help

[abubin]

I am stumped. I have been having this wifi problem for the past few month and I am still unable to find what is the problem.

In my office, I have around 50 users. We have 3 wifi APs connected through ethernet cable back to the backbone. So the APs only act as bridge for users to connect to LAN. Out of the 50 users...each APs have around 5-20 connections at one time. Most users have their own cable connection. Some need to use wifi and most of the wifi devices are connection from smartphones and tablets.

However, we keep getting constant complains from users saying the wifi connection is SLOW and frequent DISCONNECTION.

The three APs we have is:
1) Ubiquiti Unifi
2) Linksys WRT54GL (running tomato firmware)
3) Asus RT-N12

Each AP have their own SSID. They do not share same SSID. All running in hybrid mode to allow connections from 802.11a,11b and 11n. All using different non-overlapping channel, 1,6 and 11.

I tried transferring a big file connecting through ubiquiti unifi which is supposedly to be an enterprise grade AP but speed is only at best 2mbit with the AP next to it. When I start using skype video chat, connections becomes crazy bad. Lots of dropped packets with ping. Around 30% packet lost. When connection is idle, I only run ping, connection is a lot more stable. Worst is connection keep getting disconnected.

I have no idea whether this is due to the wifi devices or my setup. Any expert with any idea, please help. Also, wired connection works fine most of the times. No complains from there.

I read about using 5ghz band but does it means the clients also need to be able to run at 5ghz? Does getting a cisco AP will help in this matter?

 

[coxhaus]

I think you need to segment your network. Break your core out and then push the slower devices out farther.

 

[abubin]

I think you need to segment your network. Break your core out and then push the slower devices out farther.

err..you mean using vlan? Some of the devices need to use network filesharing. So we cannot split the wifi devices out of the LAN.

Do you mean splitting out the wifi into it's own LAN subnet? Please explain. I am really noob at this.

 

[Mark Uhde]

Ubiquiti isn't enterprise grade. EVERYTHING SHOULD BE THE SAME SSID/SECURITY. One of the biggest issues is people select the wrong AP for them causing them to connect at quite a distance and slow everyone on the AP.

Here's what I'd do though I think you may have an interference issue (see the bottom):

Trash the two non-Ubiquiti AP's. Go and buy a three-pack of the UAP-Pro's (they're dual band and support 802.3af PoE making installation to a PoE switch a breeze). Set them up properly. Yes, clients need 5 GHz to connect to the 5 GHz side (and even then some like Android it's random whether they pick 2.4 or 5) but they still benefit everyone by reducing 2.4 GHz load.

Problems likely solved. Oh, and don't use their new seamless roaming mode. That limits you to one channel.

And no, UniFi is not Enterprise-class no matter what they say. But it'll work fine for your needs, especially the Pro units.

Oh, one more thing, 30% packet loss is never normal. 20 users/AP isn't that bad. Make sure there's no interference (2.4 GHz security cameras are the worst, but pretty much 2.4 GHz anything). Get a spectrum analyzer if you can.

 

[coxhaus]

I think with 50 active users you should have local DHCP and DNS servers and probably some kind of application server. I would not use a router DHCP or DNS with this many active connections. I also assume you are running active directory.
I would build this stuff as core. Then how I would divide the rest of the network would depend on the physical layout. The methods used to divide the network would be vlans and separate networks.

 

[Mark Uhde]

I think with 50 active users you should have local DHCP and DNS servers and probably some kind of application server. I would not use a router DHCP or DNS with this many active connections. I also assume you are running active directory.
I would build this stuff as core. Then how I would divide the rest of the network would depend on the physical layout. The methods used to divide the network would be vlans and separate networks.

But he doesn't state how the wired network is connected, and he states that wired clients have no issues. Thus, his wired network seems to be fine.

There are plenty of routers that can easily handle DHCP and DNS for 50 users. Heck, that's less load than actually routing those 50 users. Obviously he needs a good router on the network, but his issue isn't in the physical network if wired users have no problems.

At first, I just saw the cruddy mis-match of different equipment with different SSIDs (which causes slowdowns for everybody if clients pick an SSID far away from them). But even all of that shouldn't be an issue with so few users. I think he has an interference problem.

Of course, the UAP-Pros would also resolve that for 5 GHz clients - but you need to hunt down the interference if there is any since I'm sure you can't have a 5 GHz only network

A NanoStation Loco M2 wouldn't be a good AP for your network, but it has a really nice (for cheap) spectrum analyzer tool built in. Consider buying one just to hunt down interference at client locations They're only $50

 

[coxhaus]

I would never spend a lot of extra money on a bigger router just to run DHCP and DNS. Microsoft DHCP is a lot better than a router DHCP. Microsoft DHCP supports multiple scopes and reservations much better and easier to use than any router. If you run active directory, you need to run Microsoft’s DNS or your active directory is going to be out of sync and you will constantly need to repair it. With 50 users you will not need to run an extra server as the domain controller will handle running DHCP and DNS just fine.

I don’t believe in one network for everything for bigger sites as it is bad planning.

 

[abubin]

thanks for the great expert advise! Really appreciate them.

Anyway, I do have active directory servers running that serve DNS and DHCP. So no problem in that part.

As for having different SSID, the reason is quite contrary to avoid users from connecting to wrong SSID. I named them by location and educated users on connecting to correct SSIDs nearest to them. So far this has been successful and I have also worked with users to make sure they connect to SSID nearest to them.

I also suspected this to be problem with signal inteference hence I switched all the APs to use non-intefering channel. This did not really solve the problem. So I am not sure how to proceed. You mentioned of doing some sort of spectrum analyzer. I have tried doing some googling on this before but all I found is having to buy extra equipment just to do that. Is there anyway to use existing equipment to do this spectrum analyzer?

Okay..opening up my iphone, I can see around 22 wifi networks out of which around 6 belong to us. Is this considered alot what will cause interference?

 

[abubin]

good news..I just found someone who can loan us a unit of ubnt nanostation m2. This can do the spectrum analyer with AirOS. Will start doing this and post results here.

Here is the result of AirView spectrum analyzer:

 

[Mark Uhde]

good news..I just found someone who can loan us a unit of ubnt nanostation m2. This can do the spectrum analyer with AirOS. Will start doing this and post results here.

Here is the result of AirView spectrum analyzer:

Definitely looks to me like you have some non-802.11 interfering signal (or 802.11 on non-1,6,11 channels)

 

[abubin]

Definitely looks to me like you have some non-802.11 interfering signal (or 802.11 on non-1,6,11 channels)

hmm..perhaps due to those using wireless mouse? Not that many users doing that though. Also, perhaps someone else using such devices. Neighbours and so on. Anyway, what's the solution?

I just blasted out an email telling everyone we will be locking down the wifi network to only those permitted to connect. But this won't solve the issue if there are noise interference in the network.

 

[stevech]

be sure to not get confused, with a spectrum analyzer, where every WiFi access point or WiFi router transmits a beacon frame 10 times a second. This is normal. Beacons are of no consequence to interference - because they are quite brief.

 

[Mark Uhde]

The levels look much stronger than a wireless mouse. You see that big swath from 2417 to 2452? Upon closer examination, that looks like a 40 MHz 802.11 channel pair on channel 7 that's seeing fairly high utilization. HUNT THEM DOWN. Sadly, if they're your neighbours there's just nothing you can do. Get the UAP-Pro's and then you'll get some of your traffic to 5 GHz which helps everyone.

You can fairly clearly see your channel 11 in that graph (and the only one that doesn't look totally swamped by noise), but look above it. It looks like a fair bit of noise all around. It's going to be a fun game to solve this. The UAP-Pro's will be a great first step and taking the time to get a network that's easier to use (all one SSID) is important for user experience. The UniFi setup is easy to do.

The second step is going around with the Loco and figuring out WHERE the interference is. The Loco is directional which helps a TON.

 

[abubin]

channel 7 is being used by UBNT unifi. I had to put both the unifi and loco near to each other due to cabling.

It's no fun with people breathing down my neck especially some high level officers who are also too lazy to use their WORKING wired connection.

Tomorrow we will be having another of our monthly management/sales meeting. around 10 people will fly in for the meeting with management. Arhhh.....

 

[Mark Uhde]

Well get off of channel 7 (and I really think you should use the same SSID/security everywhere it makes things much easier for your users!). Use 1,6,11 or 1,5,9,13 (outside NA) only. Also, it looks like it's in 40 MHz mode! Make sure everything is locked to 20 MHz ONLY in the 2.4 GHz band.

And get the UAP-Pro's to get you out of 2.4 GHz