[asterisk-biz] IAX2 ATA with 4-8 FXS ports

[Brian Candler]

On Tue, Nov 21, 2006 at 04:43:31PM -0500, Al Bochter wrote:
> Steve,
> 
> I guess the last codex you want to see is G. 711

Quite.

Going back to my original posting, I asked for three things: G729, IAX2
trunking, and 4-8 FXS ports.

I'm in the UK. Transit bandwidth is cheap, but last mile bandwidth isn't if
you want large amounts of it.

8 calls of G711 in RTP requires 848,000 bits per second [1]
8 calls of G729 in RTP requires 339,200 bits per second [2]
8 calls of G729 in trunked IAX2 requires 127,200 bits per second [3]

[1] 40 bytes header + 160 bytes payload = 200 bytes; that's 5 ATM cells;
8*50 pps; gives 8*50*5*53*8 bits per second

[2] 40 bytes header + 20 bytes payload = 60 bytes; that's 2 ATM cells;
8*50 pps; gives 8*50*2*53*8 bits per second

[3] 36 bytes header + 8*26 bytes payload = 244 bytes; that's 6 ATM cells; 50
pps; gives 50*6*53*8 bits per second

Regards,

Brian.