On 7 Jan 2009, at 18:04, Gregory Boehnlein wrote: >>> Have you done this in production? Is there an actual case study >> and/or >>> company that is doing this with the hardware that I can speak with? >>> I'd like >>> to see what performance is like with 256 active channels on a USB >> bus. >> >> Here are some practical test done by Xorcom. Depending mainly on the >> echo can tail you can get up to 240 calls with 32 taps, as the system >> has to work harder for 128 taps you only get 93... >> >> XR3000 + on board [2ports PRI] + [24FXS] >> 16 Astribanks [32FXS] >> System Total: 2 PRI, 536 extensions >> >> Setting: >> dtmf_detection=yes >> echocancel=128 >> >> Results: >> maximum load = 93 concurrent calls. > > OK.. so this might work in a system where you have a 4:1 call > ratio.. I.E. > where only 1 of every 4 channels is in use at the same time. > > This would lend itself very well to a Hotel or other "casual use" > sort of > deployment. > > What about in a call-center or high-volume PBX situation where you are > running at 1:1 ratios? > > Also, keep in mind that a PRI based card is most likely going to have > hardware echo cancelling (Octasic based) PRI based Echo Canceller > that can > do 128 tap echo cancellation on all channels at simultaneously. > > If you use E-1 signalling between the Channel Banks and the Asterisk > box, > you'll get 30 channels of usable audio (8 x 30 = 240). If you double > up the > Sangoma cards, you can have 16 PRI (480 channels) into a single box. > And > yes, I do know and have seen some people running 16 and 24 PRIs into > an > Asterisk server in the field. > > Personally, I'd rather diversify this sort of load over multiple > boxes.. say > using Digium TE412P cards + Hardware Transcoding cards. > >> ----- >> Setting: >> dtmf_detection=yes >> echocancel=64 >> >> Results: >> maximum load = 157 concurrent calls. >> >> ---- >> Settings: >> dtmf_detection=yes >> echocancel=32 >> >> Results: >> maximum load = 240 concurrent calls > > Where is the Echo Cancellation done? At the Astribank on Hardware > DSP? Or at > the Asterisk server using software echo cancellers? > > Personally, I've switched to using all hardware based echo > cancelling.. it > "just works" and it has addressed every echo concern that I've ever > run into > w/ Asterisk. I can't imagine goine back to software echo cancelling > ever > again.
At the moment it is software - I agree hardware is 1st prise! Regards Rob _______________________________________________ --Bandwidth and Colocation Provided by http://www.api-digital.com-- asterisk-biz mailing list To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-biz
