Got it. Thanks. Makes sense to keep an extra two in mind for conference etc....
Off topic - what is top post? I am using gmail + chrome - no ugly Outlook. On Fri, Jan 14, 2011 at 3:33 PM, Danny Nicholas <da...@debsinc.com> wrote: > Hurray for Microsoft Outlook (for creating this whole top-post thread). > Just my .02; The other two ports must have been a remnant of another > channel; as for the 4 ports – I think that the 4 port requirement is > probably for “niceties” like conferencing and transfers. > > > ------------------------------ > > *From:* asterisk-users-boun...@lists.digium.com [mailto: > asterisk-users-boun...@lists.digium.com] *On Behalf Of *Bruce B > *Sent:* Friday, January 14, 2011 2:15 PM > > *To:* Asterisk Users Mailing List - Non-Commercial Discussion > *Subject:* Re: [asterisk-users] Why are 4 ports used for a single call? > > > > Thanks guys. I am not sure whether that call was asymmetric or not but I > saw 4 ports open. It could be that the other two ports were remnant of > another channel even though I doubt it. > > > > Now, when I tried again, it is only 2 ports that is opened like you > mentioned, even RTP port, and RTP port +1. So, does Asterisk usually use > the symmetric method or is the asymmetric method used as well by some media > servers? > > > > The reason why I am asking is because there are many many > online responses that there is 4 ports needed per call and make sure you > keep enough ports open, blah blah... > > > > Thanks again > > On Fri, Jan 14, 2011 at 2:57 PM, Gary Allen <solsta...@gmail.com> wrote: > > RTP always uses a random even numbered port, then RTCP will use the next > port, which will always be odd numbered. Symmetric RTP only needs two > ports, while asymmetric RTP uses four. > > http://www.armware.dk/RFC/rfc/rfc4961.html > > > On Fri, Jan 14, 2011 at 12:44 PM, Bruce B <bruceb...@gmail.com> wrote: > > I mean part of RTP RFC? > > > > On Fri, Jan 14, 2011 at 2:41 PM, Bruce B <bruceb...@gmail.com> wrote: > > Hi Everyone, > > > > I am just tweaking a pfSense router and learning lots about NAT etc....I > noticed that each call uses four UDP port for RTP. Here is an example of > port for a call I made: > > > > 10200 > > 10201 > > 10504 > > 10505 > > > > Seems like they are random in pair. I have a restriction of 10000-11000 in > my rtp.conf so that makes sense. But why use 4 ports per call? is that part > of SIP RFC? > > > > Thanks > > > > > > -- > _____________________________________________________________________ > -- Bandwidth and Colocation Provided by http://www.api-digital.com -- > New to Asterisk? Join us for a live introductory webinar every Thurs: > http://www.asterisk.org/hello > > asterisk-users mailing list > To UNSUBSCRIBE or update options visit: > http://lists.digium.com/mailman/listinfo/asterisk-users > > > > > -- > _____________________________________________________________________ > -- Bandwidth and Colocation Provided by http://www.api-digital.com -- > New to Asterisk? Join us for a live introductory webinar every Thurs: > http://www.asterisk.org/hello > > asterisk-users mailing list > To UNSUBSCRIBE or update options visit: > http://lists.digium.com/mailman/listinfo/asterisk-users > > > > -- > _____________________________________________________________________ > -- Bandwidth and Colocation Provided by http://www.api-digital.com -- > New to Asterisk? Join us for a live introductory webinar every Thurs: > http://www.asterisk.org/hello > > asterisk-users mailing list > To UNSUBSCRIBE or update options visit: > http://lists.digium.com/mailman/listinfo/asterisk-users >
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