On Tuesday 23 December 2003 10:59, Rich Adamson wrote: > I'm not sure under what circumstances (from an overall performance > perspective) 20ms is better then 60ms, or the reverse. Gut feeling would In our network we set UAs to use 60ms (using G729). Actual data measurements indicate a call consumes about 13Kbps. If we use 20ms then it consumes about 25Kbps. These are of course peer-peer calls since Asterisk itself does not support transmitting at 60ms. We prefer 60ms due to the fact that some of our customers are using dial-up for their VoIP, and bigger delays are preferable to dopped packets.
Andres. > suggest choosing the size is roughly equivalent to MTU size. The 60ms > setting should result in larger packets which might be okay for high > speed uncongested links and satellite links. However, the smaller 20ms > packets effectively allow "more opportunity" for others to talk on the > wire and would likely improve response time for all devices on the wire. > > Rich > ------------------------ > > > Interesting. For the record, the MultiTech MVP-130 comes with a default > > setting > > of 60ms packets on all of its supported codecs. I changed the packet > > sizes to > > 20ms because I had never heard of anyone using such large sample sizes. > > > > Andres wrote: > > >On Monday 22 December 2003 19:58, Rich Adamson wrote: > > >>>On Monday 22 December 2003 16:37, Andres wrote: > > >>>>On Monday 22 December 2003 15:36, Rich Adamson wrote: > > >>>>>>I have a question regarding the Asterisk Packet Time for SIP Calls. > > >>>>>> It is hardcoded at 20ms but when I do an RTP Analysis on a stream > > >>>>>>it is clear that these packets are not spaced out at 20ms. In > > >>>>>>general you see something like: > > >>>>>> > > >>>>>>Packet 50 - Delay 50ms > > >>>>>>Packet 51 - Delay 5ms > > >>>>>>Packet 52 - Delay 5ms > > >>>>>>Packet 53 - Delay 50ms > > >>>>>>Packet 54 - Delay 5ms > > >>>>>>Packet 55 - Delay 5ms > > >>>>>> > > >>>>>>Is there anyway to space them out evenly at 20ms?? > > >>>>> > > >>>>>The 20 ms is not the inter-packet timing, its the relative content > > >>>>> of what's within the packet. In other words, the packet contains > > >>>>> 20ms of encoded voice. > > >>>>> > > >>>>>If the inter-packet times (delays) are large, as they would seem to > > >>>>>be in your example, then something else is not right. Possibly a > > >>>>>half-duplex ethernet connection, something else running on the > > >>>>>server, router buffers, etc. > > >>>>> > > >>>>>On a typical * --> C7960 local call, I generally see from 1ms to > > >>>>> 20ms inter-packet delays. Seldom (if ever) anything above 20ms. > > >>>> > > >>>>Thanks for your Input Rich. I went ahead and tested this on our > > >>>>production servers and sure enough the inter-packet times are 20ms. > > >>>>There must be something happening with our LAB Asterisk. It could be > > >>>>the CBQ traffic shaping software we have running on it. I will > > >>>> fiddle around with it to see if it changes anything. > > >>>> > > >>>>Thanks! > > >>>>Andres > > >>> > > >>>Ok...after some more testing, the traffic shaping software was not the > > >>>culprit. It turns out that if the UA is configured for 60ms of voice, > > >>>then Asterisk will show this strange behaviour. If we set the UA for > > >>>20ms, then all works well. > > >> > > >>Cool! > > >> > > >>How did it get set to 60ms? > > > > > >The GS Phone, ATA186, and SPA2000 all have a parameter that lets you set > > > the transmit packet size to 60ms (or multiple other values). Asterisk > > > will receive 60ms and transmit 20ms times 3 packets, andit works quite > > > well. In any case our SPA2000 problem was unrelated to the packet > > > time. > > > > > >Regards, > > >Andres > > > > > >>_______________________________________________ > > >>Asterisk-Users mailing list > > >>[EMAIL PROTECTED] > > >>http://lists.digium.com/mailman/listinfo/asterisk-users > > > > > >_______________________________________________ > > >Asterisk-Users mailing list > > >[EMAIL PROTECTED] > > >http://lists.digium.com/mailman/listinfo/asterisk-users > > > > _______________________________________________ > > Asterisk-Users mailing list > > [EMAIL PROTECTED] > > http://lists.digium.com/mailman/listinfo/asterisk-users > > ---------------End of Original Message----------------- > > > _______________________________________________ > Asterisk-Users mailing list > [EMAIL PROTECTED] > http://lists.digium.com/mailman/listinfo/asterisk-users _______________________________________________ Asterisk-Users mailing list [EMAIL PROTECTED] http://lists.digium.com/mailman/listinfo/asterisk-users
