VOIP Bandwidth

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kiwiscoota

237 posts

Master Geek

#32434 17-Apr-2009 01:06

Does anyone have any idea how much bandwidth a conventional VOIP service uses (I.E. 2 Talk).

Last month I exceeded my data allowance and I'd noticed my usage this month to date was fairly high, so I've installed a monitor program on my Mac (my primary internet computer) to monitor my internet data usage on that.

Monitoring my Skype, I've discovered that is using around 6 meg per minute with video, or about 1 meg per minute using just audio.

Would standard VOIP use a comparable amount to Skype audio only ?

sbiddle

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#207449 17-Apr-2009 06:44

What codec are you usng?

If you're using G.711 total bandwidth for a call (incoming and outgoing RTP traffic) is around 160kbps - 170kbps incl all IP overheads.

If you're using G.729 total bandwidth for a call (incoming and outgoing RTP traffic) is around 50kbps - 60kbps incl all IP overheads.

kiwiscoota

237 posts

Master Geek

#207468 17-Apr-2009 08:40

I normally use G.711, so on the basis of 170kbps, that equates to 20.75KB/s which is 1.21MB/minute which is roughly the same as Skype audio calls appear to use.

Thanks for that, I did realise that audio telephony was not going to use anywhere near the volume as Skype Video, but I was curious.

sbiddle

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#207472 17-Apr-2009 09:03

kiwiscoota: I normally use G.711, so on the basis of 170kbps, that equates to 20.75KB/s which is 1.21MB/minute which is roughly the same as Skype audio calls appear to use.

Thanks for that, I did realise that audio telephony was not going to use anywhere near the volume as Skype Video, but I was curious.

Skype doesn't use anywhere near G.711 for regular Skype voice calls, regular Skype voice calls will be in a similair ballbark region to G.729.

You could always switch go G.729, it's a pretty common codec for voice usage these days.

kiwiscoota

237 posts

Master Geek

#207476 17-Apr-2009 09:19

sbiddle:
kiwiscoota: I normally use G.711, so on the basis of 170kbps, that equates to 20.75KB/s which is 1.21MB/minute which is roughly the same as Skype audio calls appear to use.

Thanks for that, I did realise that audio telephony was not going to use anywhere near the volume as Skype Video, but I was curious.

Skype doesn't use anywhere near G.711 for regular Skype voice calls, regular Skype voice calls will be in a similair ballbark region to G.729.

You could always switch go G.729, it's a pretty common codec for voice usage these days.

Real time testing with Skype running indicated it used 70.1MB for a 10 minute call, I was rounding when I said 1 MB per minute.

I'm not really concerned about my VOIP or Skype usage at that sort of level, although obviously I need to limit my video calls as I've realised a lengthy Skype video call is creating a large volume of data traffic.

It does make me wonder whether using the likes of iChat (Google Chat), Yahoo or MSN video chat would be more economic as the video window size is much smaller.... I know in iChat it's possible in preferences to limit the amount of bandwidth allocated to iChat, and Yahoo Messenger allows the user to decide whether to use a large or small video image.

d3Xt3r

687 posts

Ultimate Geek

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#207758 18-Apr-2009 12:51

It depends on the codec used, so it varies from service providers. Betamax based providers (like VoipBuster, SmartVoip etc) use about 6.1KB/s, which works out to 366 KB/min. Thanks to the cheaper rates these days, we tend to talk more freely - even I exceeded my data cap for this month. Been on dialup speeds since a week now. Sigh :(

sbiddle

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#207761 18-Apr-2009 12:59

kiwiscoota:
Real time testing with Skype running indicated it used 70.1MB for a 10 minute call, I was rounding when I said 1 MB per minute.

If you're using that much bandwidth you're a supernode.

Unless you like giving away all your bandwidth to other users I'd suggest you do a Google search to find out how you can disable this.. Unless of course you don't mind it.

kiwiscoota

237 posts

Master Geek

#207764 18-Apr-2009 13:14

sbiddle:
kiwiscoota:
Real time testing with Skype running indicated it used 70.1MB for a 10 minute call, I was rounding when I said 1 MB per minute.

If you're using that much bandwidth you're a supernode.

Unless you like giving away all your bandwidth to other users I'd suggest you do a Google search to find out how you can disable this.. Unless of course you don't mind it.

I should read my own notes properly !

The actual usage for a 20 minute call was 70.1 meg, that call was a mix of the first 10 minutes being video & audio that used 59.3 meg, the balance of the call was audio only, which used a further 10.7 meg (10 minutes audio only).

So the video part of the call averaged 5.93 MB / minute, the audio only part of the call averaged 1.07 MB per minute

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sbiddle

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#207768 18-Apr-2009 13:36

Skype shouldn't be using anywhere near that for a regular audio call.

G.711a / G.711u are uncompressed PCM voice codecs and you're looking at something roughly around 50ish MB per hour.

Skype uses iLBC which is is a very compresses codec and will typiclaly be averaging somewhere around 20 - 30kbps on average. Even SILK (which is Skype's new super wideband codec) can deliver 24Khz sampling at a maximum of 40kbps.

How are you actually measuring your Skype bandwidth usage? And are you sure you're not a supernode?

kiwiscoota

237 posts

Master Geek

#207788 18-Apr-2009 14:39

sbiddle: Skype shouldn't be using anywhere near that for a regular audio call.

G.711a / G.711u are uncompressed PCM voice codecs and you're looking at something roughly around 50ish MB per hour.

Skype uses iLBC which is is a very compresses codec and will typiclaly be averaging somewhere around 20 - 30kbps on average. Even SILK (which is Skype's new super wideband codec) can deliver 24Khz sampling at a maximum of 40kbps.

How are you actually measuring your Skype bandwidth usage? And are you sure you're not a supernode?

According to Skype's own web site:

Skype automatically selects the best codec depending on the connection between yourself and the person you are calling. On average, Skype uses between 3-16 kilobytes/sec depending on bandwidth available for other party, network conditions in between, callers CPU performance, etc.

So Skype are claiming somewhere between 3 KB/s (24.58 kbps) and 16 KB/s (131.1 kbps ), on that basis my apparent usage (voice only) at 1.07 MB per minute is not out of the ball park (Skype @ 16 KB/s = 0.9372 MB per minute).

I've done quite a bit of research today (I need to get a life !) regarding Skype and Skype's bandwidth usage, and have changed the default port and my firewall settings as recommended on various forums to avoid the possibility of being used as a supernode, so it will interesting to monitor my next call to see whether there is any change.