Ok, as expected neighboring radios on the AU side are becoming more active and the link is really beginning to suffer now. Here are the SU counters as of this morning:
Modulation Level:| 1 2 3 4 5 6 7 8 | SUCCESS :| 54 56 82 1278 10264 2283703 0 0 | FAILED :| 18 24 39 185 583 879 0 0 | Average Modulation Level : 6 As a ratio it appears Mod Level 6 is doing the best, but I don't think that is relevant. How much throughput can be expected if I lock the Mod Level down to 1 and will that improve the VL performance in noisy environments? Ping times across the link are really getting hammered as the client is trying to push data both directions. We are seeing 4ms to 2000ms+ and approaching 10-15% loss. Thanks, Brad -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Brad Belton Sent: Wednesday, October 11, 2006 8:17 AM To: 'WISPA General List' Subject: RE: [WISPA] Are these good or bad Alvarion VL statistics... Hello Mike, Certainly the SNR is better than LEDs, but not as important or useful as a RSSI reading. As others here have pointed out it is very possible the SNR could improve by misaligning the link. A misaligned link will only cause you more trouble down the road. I'm hoping Patrick follows through and pushes the Alvarion engineers to provide it. During one of the many calls into Alvarion Support we did look into the modulation counters and we settled on forcing the AU and SU to 6. The AU counters look like this: Modulation Level:| 1 2 3 4 5 6 7 8 | SUCCESS :| 1 1 1 1 1 2760796 0 0 | FAILED :| 0 0 0 0 0 0 0 0 | The SU looks like this: Modulation Level:| 1 2 3 4 5 6 7 8 | SUCCESS :| 25 1 1 110 3604 2139679 0 0 | FAILED :| 0 0 0 7 27 85 0 0 | Average Modulation Level : 6 The SU counters were reset last night and as such do not reflect usage during business hours. I'm sure the interference increases during the day as neighboring radios at the AU side become more active. Are these acceptable results? Alvarion never suggested trying a 10MHz channel and at this point we are willing to try anything before we are forced to remove the VL gear all together. I appreciate your input. Best, Brad -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Mike Cowan Sent: Wednesday, October 11, 2006 6:11 AM To: WISPA General List Subject: Re: [WISPA] Are these good or bad Alvarion VL statistics... Hi Brad, A lot of what Dave has said is good info and my reply is a bit redundant. The lights on the bottom of the radio should really only be used for a rough indication of signal level. This is true for most radio products that offer lights for RSL. Once you have achieved association via lights on the bottom it is best to Telnet as Dave suggested and then tune for highest SNR. The lights can help here, but only roughly. If you are looking at continuous link quality display that will give you the fine indications to help you aim and achieve the best connection possible. You may also see the effects of heavy multipath while watcing this in the form of bouncing SNR. This can also be seen in the lights as little light movement. OFDM does a much better job with multipath than a traditional radio, but it does not eliminate MP type problems. Best SNR is only part of the equation. The counters also need to be reviewed and I find the Breezeconfig site survey page the easiest to read. You need to look at retrans vs total as a percentage and also look at drops which are frames rxtx that never successfully made it. You also need to look at the per rate counters, particularly if the area is noisy. The radio will auto modulate from level 8 to level 1 based on noise. The automodulation scheme is pretty decent in the radio but I klike to hard set the max mod rate when noise is present. The radio will always try to mod at the highest level and sometime that level might be close to the SNR threshold and performance may be acceptable to the algorithm but not acceptable to you. If I see the radio counters showing many fails at mod8, fewer at mod 7, and clean at mod 6 I would lock the radio to 6. No sense in allowing it to try to do better than 6 if conditions mostly won't allow it. Channel size (10 or 20Mhz) is another tool available to help find open spectrum to run on. Hope this helps, Mike Mike Cowan Wireless Connections A Division of ACC 166 Milan Ave Norwalk, OH 44857 419-660-6100 [EMAIL PROTECTED] www.wirelessconnections.net -- WISPA Wireless List: [email protected] Subscribe/Unsubscribe: http://lists.wispa.org/mailman/listinfo/wireless Archives: http://lists.wispa.org/pipermail/wireless/ -- WISPA Wireless List: [email protected] Subscribe/Unsubscribe: http://lists.wispa.org/mailman/listinfo/wireless Archives: http://lists.wispa.org/pipermail/wireless/ -- WISPA Wireless List: [email protected] Subscribe/Unsubscribe: http://lists.wispa.org/mailman/listinfo/wireless Archives: http://lists.wispa.org/pipermail/wireless/
