On Friday 03 March 2006 12:44, Shidan wrote: > Echo can. and trancoding (voice not protocols) are inherently costly, > and software is still not the best place for them, thats why good > cards still matter (thats not really why good cards matter in * > because neither Digiums or Sangomas do this yet and for the cards that > do, none of those things have been interfaced with zaptel yet). But > good cards still do matter with *!!
Echo can is best done as close to the source of echo as possible; having the echo can *after* the PCI bus just isn't the best place for it, regardless of costliness. Remember that while Asterisk itself may not be optimized for multiple processing units, the Linux kernel can punt threads off to multiple processors and the drivers can make use of having different execution units as well to do their number crunching on, which is exactly what echo cancellation is all about. ANY multithreaded application will benefit from multiple processors if the operating system can effectively schedule the threads to make use of concurrent execution and the application isn't written poorly. > As far as whats needed to make * work effectively, a sangoma card on > a P4 can handle 200 calls/second, with no transcoding. Those are really short calls! :-) -A.
