Traffic shaping recommended with VOIP?

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berend

58 posts

Master Geek

#61272 13-May-2010 07:47

Hi All,

I'm about to delve into the world of VOIP and this is really a step up in complexity compared to POT! Anyway, I like the ability to select an ISP on performance and not have to deal with land line issues at the same time.

I happen to run a FreeBSD is the main gateway on my network and I wonder if it's traffic shaping capabilities are useful when going VOIP. I.e. should I always leave 8kpbs availabe for VOIP? Do people use that? Is that recommended? Does it improve quality? And I mean especially responsiveness, I just hate those delays when talking to people.

And should it be 16kpbs instead of 8kpbs?

So like to hear from people doing that kind of thing and what their experiences are.

Thanks a lot,

Berend.

LennonNZ

2444 posts

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#329623 13-May-2010 08:02

You should look @ the codec you are using and number of VOIP calls you are making simultaneously. 8k reserved for G711 for 2 calls would be useless.

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sbiddle

30853 posts

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#329643 13-May-2010 09:16

It depends entirely on the codec you are using and the number of concurrent calls. If you're going to be using G711 or a wideband codec such as G722 than depending on your exact network overheads you are looking at somewhere around 87kbps in each direction for a call. A codec such as G729 will use roughly 1/2 this.

So QoS is important, but you need to know a lot more about what you're actually setting up and how QoS works before you start making changes.

berend

58 posts

Master Geek

#329650 13-May-2010 09:42

I get the part on that reserved bandwidth is depending on the codec, but obviously this cuts both ways: i.e. select a codec on the bandwidth you want to consume.

But is it useful? Are people doing it? Will it help with QOS? Or is the general advice: don't bother unless you have a problem?

Thanks so far,

Berend.