> I was wondering what could be pros and cons of ztdummy vs proper timer > device (i.e. X100P). > > I am going to set up an asterisk server in europe (to do trunking, to > save bandwith) and I was wondering if it'll be OK to get it going with > ztdummy. > > Furthermore, I have only a 1024/256kbps PPPOE DSL link and I need to > squeeze 12 channels through, I was wondering which codec would be > suitable for this? Is g.729a going to be indispensable or can I get away > with something like GSM?I would seriously doubt that you can actually squeeze 12 channels through that dsl and obtain anything reasonable for quality, regardless of which asterisk codec you choose. But, it certainly would not be that hard to test it and validate assumptions. If that dsl is used for anything else (including hackers/scanners hitting the IP associated with the circuit), quality will vary. Don't forget to add the IP packet overhead to the codec bandwidth estimates.
Jean-Michel Hiver wrote:> I was wondering what could be pros and cons of ztdummy vs proper timer > device (i.e. X100P). > > I am going to set up an asterisk server in europe (to do trunking, to > save bandwith) and I was wondering if it'll be OK to get it going with > ztdummy. > > Furthermore, I have only a 1024/256kbps PPPOE DSL link and I need to > squeeze 12 channels through, I was wondering which codec would be > suitable for this? Is g.729a going to be indispensable or can I get away > with something like GSM? > > Cheers, > Jean-Michel.Jean-Michel, Ztdummy can be okay, but true hardware timing WILL be better. But, as Rich pointed out, that 256kbps ADSL is probably going to hurt: 256 - 41 = 215kbps usable bandwidth (%16 PPPoE overhead) IAX2 trunking with g729: 40kbps each add. call: - 10kbps So, 215 - 40 - 110 = 65kbps You only have about 65kbps to spare, and all of this is based on ideal (theoritical) conditions. I doubt that those 12 calls will sound okay, or even work at all... But, you can always try! -- Kristian Kielhofner
I was wondering what could be pros and cons of ztdummy vs proper timer device (i.e. X100P). I am going to set up an asterisk server in europe (to do trunking, to save bandwith) and I was wondering if it'll be OK to get it going with ztdummy. Furthermore, I have only a 1024/256kbps PPPOE DSL link and I need to squeeze 12 channels through, I was wondering which codec would be suitable for this? Is g.729a going to be indispensable or can I get away with something like GSM? Cheers, Jean-Michel.
> > So, 215 - 40 - 110 = 65kbps > > You only have about 65kbps to spare, and all of this is based on ideal > (theoritical) conditions. I doubt that those 12 calls will sound > okay, or even work at all... > > But, you can always try!The thing is: how do I do that? What tools are there to test how many channels can be safely fit through? Another thing is that I was thinking that it would be possible to save bandwith by lengthening the frame length to 50 or even 90ms. I have no idea how this works or how to do it though :( Cheers, Jean-Michel.