22 Clients running on one ubnt XR2.... major trouble

[Kingsley]

Hello,
I am having some trouble with one of our setups. We have a Gate Works router board (533mhz) running Ikuras and loaded with 3 ubnt mini-pci cards. 2x SR5 1x XR2. One 5gig radio is acting as the back haul, the other as an AP. Also the 2.4gig card is an AP. We seem to be having a great deal of lag on the 2.4 AP. It has 22 clients connected, all NS2's running 3.3.1 in client mode with NAT. When the first client went on we had between 3-5mb to the client with very little lag. After more and more customers went on it got worse and worse. Now it lags up to 4000ms at times. The speed is now less than 1mb at the client. The total throughput on the AP hardly even reaches 1mb now. I have the distance on the clients and AP set to 8700m, also of late i have turned RTS/CTS set to 500 on with no improvements. I don't know what to try next????
The clients generally have 100% ccq.
Any help would be great.
Thanks in advance..

Client Signals...

00:15:6D:AB:19:1D UNKNOWN - 66 dbm 24 dbm - 90 dbm 11 0:0:0:0 d/h/m/s CLIENT Not Set
00:15:6D:AB:A7:85 UNKNOWN - 59 dbm 31 dbm - 90 dbm 11 0:0:0:0 d/h/m/s CLIENT Not Set
00:15:6D:A7:C6:05 UNKNOWN - 65 dbm 25 dbm - 90 dbm 11 0:0:0:0 d/h/m/s CLIENT Not Set
00:15:6D:AB:A8:4F UNKNOWN - 61 dbm 29 dbm - 90 dbm 11 0:0:0:0 d/h/m/s CLIENT Not Set
00:15:6D:A9:63:DF UNKNOWN - 62 dbm 28 dbm - 90 dbm 11 0:0:0:0 d/h/m/s CLIENT Not Set
00:15:6D:A9:65:10 UNKNOWN - 66 dbm 24 dbm - 90 dbm 11 0:0:0:0 d/h/m/s CLIENT Not Set
00:15:6D:A9:65:13 UNKNOWN - 68 dbm 22 dbm - 90 dbm 11 0:0:0:0 d/h/m/s CLIENT Not Set
00:15:6D:AB:A8:45 UNKNOWN - 70 dbm 20 dbm - 90 dbm 11 0:0:0:0 d/h/m/s CLIENT Not Set
00:15:6D:A9:DD:1A UNKNOWN - 61 dbm 29 dbm - 90 dbm 11 0:0:0:0 d/h/m/s CLIENT Not Set
00:15:6D:A9:1E:5C UNKNOWN - 61 dbm 29 dbm - 90 dbm 11 0:0:0:0 d/h/m/s CLIENT Not Set
00:15:6D:A9:63:D5 UNKNOWN - 66 dbm 24 dbm - 90 dbm 11 0:0:0:0 d/h/m/s CLIENT Not Set
00:15:6D:A9:64:0B UNKNOWN - 70 dbm 20 dbm - 90 dbm 11 0:0:0:0 d/h/m/s CLIENT Not Set
00:15:6D:AB:A8:4A UNKNOWN - 64 dbm 26 dbm - 90 dbm 11 0:0:0:0 d/h/m/s CLIENT Not Set
00:15:6D:AB:A8:51 UNKNOWN - 67 dbm 23 dbm - 90 dbm 11 0:0:0:0 d/h/m/s CLIENT Not Set
00:15:6D:A9:62:C9 UNKNOWN - 69 dbm 21 dbm - 90 dbm 11 0:0:0:0 d/h/m/s CLIENT Not Set
00:15:6D:AB:A9:75 UNKNOWN - 63 dbm 27 dbm - 90 dbm 11 0:0:0:0 d/h/m/s CLIENT Not Set
00:15:6D:A9:64:46 UNKNOWN - 65 dbm 25 dbm - 90 dbm 11 0:0:0:0 d/h/m/s CLIENT Not Set
00:15:6D:A9:64:50 UNKNOWN - 60 dbm 30 dbm - 90 dbm 11 0:0:0:0 d/h/m/s CLIENT Not Set
00:15:6D:AB:A8:42 UNKNOWN - 58 dbm 32 dbm - 90 dbm 11 0:0:0:0 d/h/m/s CLIENT Not Set
00:15:6D:AB:A9:92 UNKNOWN - 67 dbm 23 dbm - 90 dbm 11 0:0:0:0 d/h/m/s CLIENT Not Set
00:15:6D:AB:A7:EA UNKNOWN - 61 dbm 29 dbm - 90 dbm 11 0:0:0:0 d/h/m/s CLIENT Not Set
00:15:6D:A7:C6:06 UNKNOWN - 65 dbm 25 dbm - 90 dbm 11 0:0:0:0 d/h/m/s CLIENT Not Set


Some results from one of the Nano's

'ifconfig'

wifi0 Link encap:Ethernet HWaddr 00:15:6D:A9:64:46
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:5948995 errors:351 dropped:0 overruns:0 frame:90674
TX packets:1633565 errors:103299 dropped:89 overruns:0 carrier:0
collisions:0 txqueuelen:199
RX bytes:2243101786 (2.0 GiB) TX bytes:379607709 (362.0 MiB)
Interrupt:3 Memory:b0000000-b00ffffc



'iwconfig'

ath0 IEEE 802.11b ESSID:"UniFone-HR"
Mode:Managed Frequency:2.462 GHz Access Point: 00:15:6D:54:F0:80
Bit Rate:1 Mb/s Tx-Power=16 dBm Sensitivity=0/1
Retry:off RTS thr=500 B Fragment thr:off
Encryption key:1352-E792-F3D8-20E8-DBA3-BA62-9918-530E Security mode:restricted
Power Management:off
Link Quality=65/94 Signal level=-32 dBm Noise level=-97 dBm
Rx invalid nwid:54 Rx invalid crypt:0 Rx invalid frag:0
Tx excessive retries:0 Invalid misc:0 Missed beacon:0
[/img]

[UBNT-Mike.Ford]

Can you set the framentation threshold on the AP and CPE's to 768?

Thanks,

Mike

[skyhook]

Can you perform a test disabling wireless encryption?

[skyhook]

Have you solved?

[ElementX]

The issue lies with the throughput. The XR2 has a maximum practical throughput of 17Mbps as we tested it, so if you're trying to put 22 clients on it with a bandwidth of 1Mbps each, it's definitely going to give you problems. My guess is that you're using an omni antenna with your setup. Omnis are not recommended for high-user-density areas where the users are running latency sensitive applications such as video chat, online gaming, etc. That's why base stations now use 2 x 2 MIMO antennas for a good cell coverage where a significant client density is expected or exists.

As for your problem and its cure. Don't go for a different base station right away. What is your TX power? Too high TX power can also cause such problems. Also, do not use an amplifier if you're using one. If you really have to - to extend your range - use an amp no more powerful than 500mW. You can also try to lower your TX power to perhaps 20dBm. My personal experience says that 15dBm works pretty well giving you a good range and good throughput if you have a sound fresnel zone clearance. Lowering down your TX power will probably help you get rid of the problem for now.

BR,
E|eX