On Tue, 01 Jul 2008 17:57:31 -0500, [EMAIL PROTECTED] wrote: >I would like to hear your favored method to obtain an empirical measure >of latency in the media path. >I'm doing several things that bring the media path through asterisk, and >this would allow me to make informed decisions about > >(a)PSTN termination providers >(b)DIDs in local and remote locations (and variance between ITSP's) >(c)time to/from various cellular networks (and variance between ITSP's) > >Thanks! Your opinion would be greatly appreciated >-Karl Fife > >p.s. >Speaking of latency, I've noticed that some sip endpoints (i.e. Aastra >57i Wireless) add significant latency. It would be interesting to do an >apples-to-apples comparison between with various fxo/dect, sip/dect, >wi/sip, fxo/Spread-spectrum digital , and fxo/analog 47/900/2400mhz.
I had a project not long ago where I thought I was going to have to make a comparison between the latency presented by two different call paths. In the end it wasn't necessary, but it did get me thinking about what I could do, lacking for any special equipment. I had thought that I'd locate an echo test on a remote server. Free World Dialup still runs one that's accessible by both SIP and IAX2. My hosted PBX provider has one accessible via PSTN or SIP. Then I'd use a mechanical click generator (impulse) at the handset while recording the call. Then take the recording into a waveform editor software and measure the timing differences between the various paths. I can't say that this would be any kind of recommended practice, but I do think that I could get a sense of the comparative path lengths/timings. Michael -- Michael Graves mgraves<at>mstvp.com http://blog.mgraves.org o713-861-4005 c713-201-1262 sip:[EMAIL PROTECTED] skype mjgraves [EMAIL PROTECTED] _______________________________________________ -- Bandwidth and Colocation Provided by http://www.api-digital.com -- AstriCon 2008 - September 22 - 25 Phoenix, Arizona Register Now: http://www.astricon.net asterisk-users mailing list To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
