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High Ping times when one person donwloads a big file

Posted: Fri Dec 08, 2006 7:20 pm
by skywerx
What would cause the ping times to all of the other clients to rise by about 150 ms when one person on the AP is downloading a file at about 2 Megs? Are there any settings that would help prevent this? The average ping times are around 45 ms, and when this person is downloading they go up to 200 + ms.


Thanks

We are Experiencing the Same Problem

Posted: Fri Dec 08, 2006 10:15 pm
by boriss
On the one AP, we have 25 clients and everything is ok as long as nobody download or upload larger file like 1 and a half MB. We are running MT-OS on intel P4 motherboard. We try so many options and different kind of set-ups and no results. We are sure that's the problem is the software limitation. Our ping times are 2-7 mili-second, soon as somebody use steady bandwith more than one and a half MB, pings jumping up to 2000 mili-second. Second after we reboot costumer that downloading ping and performance come to normal. We are useing 5.8 MHZ.

Best Regards,

ICA

Posted: Sun Dec 10, 2006 8:46 pm
by jd6strings
But how could one person downloading at about 2.5 megs cause everybody else on the AP to have ping times above 150 ms when they are average about 25-35 ms.

Posted: Mon Dec 11, 2006 2:49 am
by UniKyrn
If you're using 802.11B, then you've only got about 3.3Mbits of usable bandwidth, so 2.5Mbit is a sizable piece of that. Depending on how many other customers you have connected, it's probably just keeping the radio busy with that one heavy data stream and polling everybody else duing the poll loop.

Posted: Mon Dec 11, 2006 10:37 am
by normis
just set up queuing with limit-at and max-limit. when there will be free bandwidth (you set the total limit also) then the download will be fast, when all users are browsing - the one persons limit will be lower.

Posted: Mon Dec 11, 2006 6:54 pm
by skywerx
Can you post an example of your queues configurations. We have tried to set a few but this resulted in extreme packet loss. We are running 5 ghz 10mhz channels with approx. 48 customers on the ap. The average AP bandwidth utilization is approx. 1.5 megs.


Thanks

Posted: Mon Dec 11, 2006 8:01 pm
by variable
what is the max bandwidth that 10mhz channels can support? maybe you have maxed that out?

Posted: Tue Dec 12, 2006 8:38 pm
by nickb
just set up queuing with limit-at and max-limit. when there will be free bandwidth (you set the total limit also) then the download will be fast, when all users are browsing - the one persons limit will be lower.
I had problems doing that via RADIUS, but I haven't tried in probably 20 revisions of RouterOS...

Posted: Wed Dec 20, 2006 7:14 pm
by jd6strings
Can somebody post an example of the queing that Normis is referring to? Thanks!

Posted: Thu Dec 21, 2006 3:00 am
by BurstNET
with radius config examples would be helpful....

Posted: Thu Dec 21, 2006 12:18 pm
by Hellbound
2 MEG means 2 Mega bytes ? or 2 Mega bit?

if two megabyte is the case then you need to cap each person to 1.8 or 1.5 Megabytes per second so no one can actually fully use the channel at maximum the speed, this is the point of weakness in Wifi Technology that does not have QOS at hardware layer like Wimax

however if it is 2megabit per second then you must try to squeeze the noise in your access point or get your own channel. reposition antenna to place that receive less noise from apartments which usually have lots of AP running in them...

other than that you might need a signal inspection on your site.

hope it helps.

Posted: Thu Dec 21, 2006 12:20 pm
by Hellbound
Can somebody post an example of the queing that Normis is referring to? Thanks!
check wiki link at top of this forum (second from right right at left top corner of the screen)