Hi Everyone

I have a 802.11a, NStream backhaul wireless link running between two buildings over about 160m, using panel antenna's at each end. The link itself works fine.

One of the interesting things I have observed is that when the link is carrying a large volume or traffic, the CCQ will hover between 95% and 100%, but during periods where there is negligible traffic across the link, the CCQ will drop down to a much lower value, typically in the order of 60 to 70%.

It's not something that has worried me too much as the link is rock solid under load and I'm not experiencing any problems, but I'd be interested in knowing if it is normal for the CCQ to drop down like this when there is no traffic being carried across a link.

Regards

Richard

I've noticed this as well, though not as much of a drop. I'll pay more attention to it.

Never had a problem though.

when there isn't any traffic, does the wireless speed associate at a higher rate?

No, the rate at which the link associates is very stable and generally it sits at 54MBit/54MBit. You will see it momentarily drop to 48MBit every couple of minutes, and very rarely you might see it drop to 6MBit, although the % CCQ doesn't appear to change much at all when the link momentarily associates at a lower rate.

In general the link is fairly robust and stable. The link does drop once every 7 or so days due to extensive data loss, although interestingly that has only been a recent thing which started happening after each AP was upgraded from 2.9.X to 3.X.

and I should probably note that when the link carries a heavy traffic load the wireless speed does in general remain solid at 54MBit. The momentary associations at lower speeds are much more common when the link is quiet.

and I should probably note that when the link carries a heavy traffic load the wireless speed does in general remain solid at 54MBit. The momentary associations at lower speeds are much more common when the link is quiet.

I observed the same behaviour during my indoor tests in turbo mode with two RB333 (ROS 3.9) and two XR5.

anyway speed and CCQ are good and stable during traffic load.

I can't speak to the CCQ levels but I can tell you that it is completely normal and by design that any card with an Atheros chipset will idle at the lowest modulation (i.e. 6Mbps) when no traffic is present.

Ahhh, that would explain it then as both cards use the Atheros chipset. I'm guessing the CCQ is partially derived from the speed at which the cards have associated at which explains the variation.

Thanks