landysaccoun
join:2008-10-10
| High latency when using VOIP
Hello.
I dont know if this is the correct forum for this question. I didn't know where to post it but, here it goes.
I was testing an Asterisk server and it work ok. I tried to add it to our WLAN and it works but, the biggest problem I have is that when I'm using it talking to another user (wireless) using x-lite at both ends I noticed that the latency goes up incredibly to over 1500ms. I don't know if is being caused by the voip traffic or noise somewhere.
Has anybody used voip in their WLAN? |
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kewlkeed
Grouch
Premium
join:2005-02-05
Knowlton, QC
| Normally it will work quite well, but it all depends on the wireless link. Can't make much of a judgment till we know more about the link. Also what codec and bitrates are you using on Xlite etc?
I've done some extensive Asterisk/VOIP over WLAN work, and it can be pretty quirky at times. |
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landysaccoun
join:2008-10-10
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Well, my WLAN consists of one central tower running a MT 433ah using an omni (this is only an emergency, untill I get some panels) with about 23 customers connected to it. From the cetral tower I have a link to another tower this one with 4 panels and MT 600 with aprox 25 customers. From this tower I have a smaller tower linked to it where I have about 8 customers connected to.
I beleive I'm using the ulaw codec since I haven't changed any settings on the xlites. I wanted to use gsm but, had problems getting installed and working.
VOIP is a service I would like to offer my customers but need to get it to work smoothly along side regular WLAN traffic. I dont know if I'd have to use 5.8Ghz freq in order for me to do that since there's so much noise around my area. |
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gunther_01
Premium
join:2004-03-29
Saybrook, IL | reply to landysaccoun
So your daisy chaining your sites, all with 2.4??
That may be your biggest problem. You also didn't say where your pings are spiking at along that chain, unless your bridging as well |
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landysaccoun
join:2008-10-10 |
I'm not bridging. I was thinking of replacing the links with 5.8 NanoStation5. I'll have to test these. Have anyone used it? What you think of these units? |
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smeghead
join:2009-02-11
| reply to landysaccoun
Use Trixbox and Xlite and Wifi all the time. No problems at all.
You need a good amount of bandwidth to use it though if the connection speed is low like 1500 down 500 up it'll be crap. Bandwidth and queue control is basically dropping packets to keep it within its speed so it distorts the voip. So the less packets you drop the better. We notice our customers once they move up to a 5Mbit package their voip is clear. |
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Inssomniak
Premium
join:2005-04-06
Cayuga, ON
| reply to landysaccoun
We have a few customers that use voip without complaints, but we dont support it really, my router does the QoS on it, but we wont support the quality of voip calls,. But the customers I do ask about it that have it says it works fine. on 1.5m/384k plans. |
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Nitroxide
join:2009-06-05 | reply to smeghead
A voip call uses hilariously low levels of bandwidth. You just need quick packets. A ms time of 1500 is seriously wrong. Can you do a traceroute or find out where all that latency is coming from? |
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GNca George
GorillaNET
Premium
join:2008-07-12
Minden, ON
| The 711 codecs use 80Kbits in both directions at once.
You can typically get by with quite a bit of latency, but VoIP hates jitter.
We use nothing but VoIP across our wireless network, seldom if ever have any problems.
George
--
Tough Broadband for a Tough Crowd!
GorillaNET.ca - 10Mbits to your desk, coming soon. |
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landysaccoun
join:2008-10-10
| reply to landysaccoun
The tests I performed were within the WLAN not going out to any voip provider. The Asterisk server is at the central station though and one client at the central station and the other as far as it could be going through a couple of links. I'm not limiting any speed or bandwidth. |
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JEhmanCTI
join:2008-02-06
| reply to landysaccoun
VoIP is all about packets-per-second and not bandwidth. Using Mikrotik and daisy chaining is a very risk set-up to offer VoIP. I don't know the PPS on them but you should really check on that.
We have customers doing VoIP over wireless but they are mostly Canopy. I am sure they are out there, but I haven't run across too many people that have entire Mikrotik PtMP systems and offer reliable VoIP.
Also, have you looked at a hosted solution yet? There are services available where you can ride off someone else's switch and just pay by the line. Very good solution to piggy-back off of until the revenue is high enough to justify buying robust hardware...
-Jeff |
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kewlkeed
Grouch
Premium
join:2005-02-05
Knowlton, QC
| reply to landysaccoun
Ditto everyone else here. Jitter and PPS is what it's all about. Also Daisy Chaining (ESPECIALLY in 2.4Ghz) is baaaaaaad for VOIP. I have yet to see a reliable example of it working well in that style of setup. So much so that I've removed any form of 2.4 "relays" on our network. Everything has a 5.8 or higher backhaul.
The gear that scares the shit out of me for VOIP at the moment, and I'll highly recommend against, for the moment, is the Ubnt Airmax stuff. Airmax causes all kinds of wacky jitter from 2-100ms for what seems to be nothing. This is apparently normal for Airmax as well. There is soon to be a massive upgrade for all of the units that removes ACK and other issues to make them a more TDMA platform, which should stabilize that. (Just as a quick FYI)
I would be very hesitant on deploying VOIP if your network is not 1000% up to par everywhere else. It will show the holes and gaps in the network like huge gaping craters with strobe lights.
--
Justin - DSLR resident grouch and Mr Negativity
TSI Fanboy - "Dontchya wish your 'net was hot like mine! Ohhh Dontchya!"
Have a nice day! |
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thewisperer
Premium
join:2008-01-16
 ·TekSavvy Solutions..
| i have a Nano5M at home running of the Rocket with sector (1 mile link: the one I posted the screenshot of a few days ago)
I am running Vbuzzer of the Nano5m at home and quality is 100%
I have a few customers running Vbuzzer with no problems.
Some probably are running voip and don't tell me. Easy to spot: traffic both ways at 80k |
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kewlkeed
Grouch
Premium
join:2005-02-05
Knowlton, QC | reply to landysaccoun
Are you running it in airmax mode or straight?
The above jitter only seems to show itself when running in Airmax mode. When running straight they don't show it at all. |
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landysaccoun
join:2008-10-10 |
Straight mode actually. |
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smeghead
join:2009-02-11
| reply to landysaccoun
Voip does use very little but it depends on the method of your bandwidth control. If you use a method that drops packets to keep the speed down, tarpitting and so forth it will affect voip that is why I say in some regards the faster connections are better, because it drops less packets including voip packets. |
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