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Thinking of moving to voip.ms and switching to Rogers Internet. Basically leaving Bell completely behind.

Just curious what sort of bandwidth usage a voip call is? Just looking at my Sympatico and our web usage is about 13 GB a month. I guess not downloading movies really saves a lot. :)

Anyhow, I'm just trying to decide what level of Rogers high speed Internet to get so I need to add our voip usage to our web usage to figure it out.
 

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I have digital phone through my ISP and unless you are going with a 2GB plan, I don't think you have to worry much about bandwidth use from digital phone. I think it is negligible compared to even just having one computer updating per month.

Someone probably has the exact calculation, but when I'm away from home, my usage is only 1 or 2 MB per day (taking maybe 2 or 3 voice mail messages) + some used syncing up I would assume. Using 13GB per month digital voice (unless you talk 24/7) will probably just amount to a rounding error.
 

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VoIP data usage depends entirely on two factors;

- your choice of codec
- your talk time

At the high end of the scale, the G711u codec (64Kbps) uses about 85Kbps per channel i.e each side of the conversation, which equates to approx 600MB per hour.

I've never checked it, but figure our average 30hrs/month talk time equates to around 18GB usage.

At the lowest end of the scale, the G729a codec (8Kpbs) is the one used for mobile phones and uses 1/8 of the bandwidth numbers given above. However, you might notice a degredation in voice quality.

The bottom line is that even at the highest voice quality codec and your current 13GB/mo usage, your total should be well within the limits of Rogers Express plan.

Also note that although there are lower-tier cable plans available, I wouldn't recommend taking anything with less than 500Kbps uplink, especially if there's a chance you might avail yourself of the "free" (call time only) 2nd line option on many ATA's. Two simultaneous G711u calls will use ~170Kbps of the uplink and many of the Lite plans are constrained to 256Kbps, which doesn't leave much room for other internet activities while you're on the phone ;)

Finally, before pulling the trigger on the Rogers deal, you might be able to save yourself ~25% by inquiring if Teksavvy cable (Rogers reseller) is available in your area. The added benefit is their Express plan currently provides 200GB/mo vs. 60GB on Rogers.
 

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I guess I don't talk on the phone much. Never realized bandwidth usage could be so high from the phone. Great info! Thanks.
 

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Silly me, forgot to convert bits to bytes; 8 to 1, plus stop/start = 10bits per Byte transferred. Plus, using the windows calc, I didn't bother with 1K = 1024

However, I think Mango misquoted on G.729, which really is 8Kbps, per Wikipedia;

G.729 is an audio data compression algorithm for voice that compresses digital voice in packets of 10 milliseconds duration. It is officially described as Coding of speech at 8 kbit/s
 

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G.729 is indeed an 8 kbit/sec codec but in reality it uses more with overhead. I've been looking around for references but not everyone agrees with the 24 kbit/sec number. However, it will for sure be a great deal more than 8 kbit/sec. For the same reason, G.711 is actually a 64 kbit/sec codec but uses 85 kbit/sec as you mentioned.

One advantage to IAX, the Inter-Asterisk eXchange protocol, is that multiple channels trunked together use less overhead bandwidth. Though it's not particularly useful for us end users since few ATAs and IP Phones support it.

m.
 

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M,

Not sure on the source, but I don't buy for a nanosecond that IP overheads etc. are tripling the bandwidth requirement for G729; the wireless companies would be freaking out and swithing codecs in a hearbeat.

64:85 is about a 30% increase, and since IP packetization is a fixed process, I'd be expecting G729 is 1/8 of G711, so about 10.5Kbps with overhead.
 

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8 to 1, plus stop/start = 10bits per Byte transferred.
Computer networks don't use start & stop bits. Those were used with asyncronous serial ports. With computer networks, including ethernet & IP, data is sent in blocks with headers. So, there is some overhead, but it's not as simple as 8 + 2. When you use voice over IP, there will also be the signalling overhead, for controlling the call.
 

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so about 10.5Kbps with overhead
The signalling or call control data will be constant, no matter what codec you're using. One type of non-SIP VoIP equipment I have worked with allocated 8 Kb/s for signalling on top of the voice bandwidth. So, if configured for G.711, you'd need 64 + 8 Kb/s and G.729 required 8 + 8. I haven't looked at the requirements for SIP, but the same principles apply. There's also the IP overhead to consider. Another thing is SIP sends out data at fixed intervals (20 mS IIRC). Each one of those packets requires the same IP overhead, whether G.729 or G.711, so as you increase compression, a greater portion of what you send is IP overhead.
 

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To the OP, it seems like a 1 to 2 GB a month for one hour a day on the phone is probably a good rule of thumb. Whether your closer to the 1 or 2GB would seem to be codec dependent.
 

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Are you asking about how much bandwidth it will consume in a month? Or how much speed do you need for a good quality call? For the bandwidth, you need to know how many hours you will stay on the phone. They are right though, I don't think you need to worry about it unless you will be spending hours and hours everyday on the phone.
 

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VoIP data usage depends entirely on two factors;

- your choice of codec
- your talk time

At the high end of the scale, the G711u codec (64Kbps) uses about 85Kbps per channel i.e each side of the conversation, which equates to approx 600MB per hour.

I've never checked it, but figure our average 30hrs/month talk time equates to around 18GB usage.

At the lowest end of the scale, the G729a codec (8Kpbs) is the one used for mobile phones and uses 1/8 of the bandwidth numbers given above. However, you might notice a degredation in voice quality.

The bottom line is that even at the highest voice quality codec and your current 13GB/mo usage, your total should be well within the limits of Rogers Express plan.

Also note that although there are lower-tier cable plans available, I wouldn't recommend taking anything with less than 500Kbps uplink, especially if there's a chance you might avail yourself of the "free" (call time only) 2nd line option on many ATA's. Two simultaneous G711u calls will use ~170Kbps of the uplink and many of the Lite plans are constrained to 256Kbps, which doesn't leave much room for other internet activities while you're on the phone ;)

Finally, before pulling the trigger on the Rogers deal, you might be able to save yourself ~25% by inquiring if Teksavvy cable (Rogers reseller) is available in your area. The added benefit is their Express plan currently provides 200GB/mo vs. 60GB on Rogers.
There are many websites where you can check you r internet speed. Just do a simple google search. It is true the faster your internet the better your connection, but generally it does not take much bandwidth to get a perfect connection and it does not generally slow down your internet from using a computer phone. Most VoIP Service is a perfect call quality and most basic internet companies have more than enough internet speed to get a great connection.
 

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I have a Cisco SPA122 ATA and I find I'm using about 15MB per day with the phone on the hook, that is no phone usage at all. The ATA continuously sends/revieves small SIP messages (one packet every 3-4 seconds) to and from the internet. Each packet is about 400 bytes.
 
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