Asterisk Bandwidth Requirements (Monthly quota)

Hi all,

I have a client who will be running 8 to 10 calls at once for most of the working day, around 8 hours or so.

The DSL connection has a little over a 1000Kbit of back channel and over 20Mbit of downstream, so I should be able to squeeze just enough connections on the one line given that this will be the only traffic on the line.

If they run G711 codecs through a SIP connection to an ITSP, roughly how much monthly data should I allow for on the DSL connection, based on say 6 days per week, 8 hours per day, and around 10 calls going at a time :question:

Please show your workings for extra marks :wink:

Looking forwards to your replies

Kind Regards
Chris says the bandwitdth required for G711 is 87,2 Kbps (kilobit per second), so it should be 87,2210606086*4, something like 140 GB per month (better check it yourself too :smile: ).


Marco Bruni


Just checking this out…

87.2Kbps (Kbits per second) = 10.9KBytes per second
2 (both directions) x
10 callers x
60 (Seconds to minutes) x
60 (minutes to hours) x
8 (hours per day) x
6 (days per week) x
4 (weeks per month) =~ 151Gb as they say a megabyte is 1,000,000 bytes !!!

Now I checked out
and for a single SIP call it suggests:
Total bandwidth (incoming and outgoing): 95.26 Kbps, 0.09 Mbps, 11.91 KBps, 0.01 MBps.

So using the above I may only need…

11.91KBps (KBytes per second)
10 callers x
60 (Seconds to minutes) x
60 (minutes to hours) x
8 (hours per day) x
6 (days per week) x
4 (weeks per month) =~ 82.32Gb based on their 1,000,000 byte calculations


Any comments anyone ??


The only issue can be and normally is that once you push any thing over 45% of the bandwidth with continuous RTP traffic, collisions become a issue.

So as you say you have 1000K then I would say that will allow you 6 concurrent calls before you start getting complaints.


Is it just the RTP traffic issue ?

On a 20Mbit down and 1MBit up ADSL2+ link I managed to have 3 calls with around 70% back channel used up with bit torrent uploads. No complaints. Mind you, it wasn’t a commercial concern.

Then again the RTP traffic would have been QoS tagged. If all the traffic is the same, with the same QoS, then it could all turn to mush.

Out of curiosity, what is the most number of simultaneous G711 calls that any of you out there have had on an ADSL2+ connection 20Mbit/1Mbit

Would be interested to have your feedback

Chris :smile: