| Author |
VOIP bandwidth problem
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| supergoku0 2002-02-04, 12:08 am |
| Hi all,
I have questions for you VOIP experts...
Is it a big issues for a point-to-point VOIP service between remote locations if "ping delay" between two ends is as large as 580ms (Routers=cisco 1750, meduium is Satellite)
Suscribed bandwidth is 128k but the voice quality is poor and often only one side can hear but the other can't after some time.
TIA,
Goku | |
| haseeb_eng 2002-02-04, 12:22 am |
| well i believe so even 64k is enough for VoIP if configured properly . | |
| supergoku0 2002-02-04, 1:49 am |
| However have you guys experienced problems if the latency is as worse as 580ms? I just received feedbacks from another forum which quotes latency worse than 180ms would become unacceptable.
Thks!
Goku | |
| haseeb_eng 2002-02-04, 3:31 am |
| ya you are right about 180ms . May be there could be a missmatch on bandwidth on both sides . | |
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Try doing a traceroute and see if any intermdeiate stations are experiencing congestion.
Hippo | |
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| Typically we use 100mS as a guide but I know that it is documented as 175mS, it varies with manufacturer, your delay is well above what is recommended.
The delay your getting is merely due to the distance of your satellite from earth. For a geostationary satellite which is what your using the orbit is 26000 Km above earth - that's a round trip of 52000 Km. It has to be this far up to keep its orbit it isn't negotiable.
The delay your getting is typical when using satcomms, when I used to work on satellites we had calculated the delay to be about what your getting, though I'm trying to do the calculation now and can't get it!! Remember the satellite is approx 26000Km above earth to maintain its orbit.
We even had phones running at 4k8 and less, it sounded crap due to the delay and the low bandwidth but we had to accept it. We were using celp, not VOIP, which I don't think will affect it unless the packets are being dropped due to the delay.
I don't think your 128K is the issue, though I can't explain why one half of the conversation is getting lost, maybe the delay is also causing this. As did we, you will have to accept the delay.
Hope this helps. | |
| supergoku0 2002-02-04, 9:53 am |
| Really appreciate your responses gentlemen.
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| AllenCole 2002-02-04, 12:06 pm |
| You have a delay budget of 200 ms. The delay has several components, but the ones you care about are the serialization and the delay due to distance. Serialization has to due with the speed of the link. If you have a 6 mbps satellite channel, your delay will be less than for a 128K channel. There is little that you can do about the distance up and back from the satellite. If you have a fast enough link, and you have your router configured so that the voice packets have first priority, you may get it to work. I haven't sat down with the math to see if it is possible.
Allen | |
| jwalters 2002-02-05, 9:17 am |
| VOIP is the stuff the phone companies love. Luckly no one here wants it. | |
| AllenCole 2002-02-05, 2:28 pm |
| quote:
Originally posted by jwalters
VOIP is the stuff the phone companies love. Luckly no one here wants it.
Yup. VOIP sucks. I like the Cisco ethernet telephone technology though--every phone an XML browser. The design considerations are very similar. |
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