Is possible to trunk SIP calls?

[mobilexpi]

Hello,
I've a small WISP and bandwidth here is very expensive, I want to know if there's possible to trunk some SIP calls or another solution to reduce bandwidth consumption of the voice calls?

Thanks

[WHT]

Sorta sounds like you are looking for an Asterisk type solution.

[mobilexpi]

I'm installing a asterisk based PBX (VoipNOW). The problem is that my ITSP offers me the DID numbers and voip terminations only via SIP and they don't support IAX.

Best regards

[WHT]

Other than getting a 24 channel T1-PRI for voice, you don't have many options for DID numbers.

[Willtech]

You are able to have DID's assigned to a SIP termination point in your Asterisk box and transport it across your APs.

[WHT]

You are able to have DID's assigned to a SIP termination pointHow will he get those DID numbers? By copper or internet connection? If its by internet connection, that's what he wants to avoid.

[mobilexpi]

I get DIDs via Internet (a national ITSP).
Via PSTN or E1 are very expensive.

[WHT]

But I thought the way you described it, bandwidth was also too expensive.

[mobilexpi]

Really dedicated connection are expensive...more than $400 per month
ADSL (1024/512Kbps) costs $70
And an E1 (30 channels) costs $380

I want to use one ADSL (just for voip, no other data traffic) for SIP calls.
I see that IAX (using trunking) supports simultaneously up to 40 calls (using 512k), but using SIP I can only manage up to 9 calls (aprox. 50kbps per call)

[WHT]

I want to use one ADSL (just for voip, no other data traffic) for SIP calls...using SIP I can only manage up to 9 calls (aprox. 50kbps per call) Since VoIP requires symmetrical speeds and you only have 512 Kbps upload speeds, you can only support about 9 or 10 VoIP call with that $70 DSL line.

[mobilexpi]

OK. And what is the standard ratio between active calls (simultaneous) and total voip users in the network??

best regards

[WHT]

There is no standard ratio for over subscription.

You could sign up 200 people and if the probability of more than ten people using it at the same time is slight, then you'll be all right.

All you can do is empirically discover the number of user that start complaining of not being able to use the service. That's when you'll need another DSL line.

[mobilexpi]

Thank you for the explanation. :)

best regards

[rviteri]

Since VoIP requires symmetrical speeds and you only have 512 Kbps upload speeds, you can only support about 9 or 10 VoIP call with that $70 DSL line.


You can always get G.729 licenses it will decrease your bandwidth requirement to 32kbps at 20 ms payloads. At 512 kbps you will have 16 concurrent calls.

http://conft.com/en/US/tech/tk652/tk698/technologies_tech_note09186a0080094ae2.shtml

[vrivera123]

I would suggest you look at the freeswitch open asterisk project(look on sourceforge). it now has a new name. basically it's an all in freeswitch, pbx, asterisk, firewall, and more. it allows for tons of calls, and it's free.

Next, i would give teliax a try. 10 bucks will get you an account that you can use for iax, and sip. and you can run some tests and get yourself real answers.