On Sat, 20 Jul 2013 12:59:19 +0200, Werner Dittmann wrote: > Sending media (real-time media) via TCP is not a good idea. TCP is > a protocol that gives some gurantees regading the sequence and some > other attributes, such as guaranteed delivery. Because TCP sits on > top of a non-reliable protocol (IP) and thus employs several > techniques to implement these gurantees. It obviously depends on circumstances, probably Mr. Haomiao Huang has a fast processor or network so maybe time is not an issue (most popular OSes aren't real-time OSes too, we use them nevertheless). It would be not a good idea to discourage him to work on this topic. :-) > TCP uses buffering and sliding windows etc (for more details have > a look into the relevant RFC :-) ) and this adds to the delivery and > round-trip time. TCP is not a real-time protocol. TCP is also vulnerable > to what's called "buffer-bloat" in the Internet. This could lead to a > large delay of data and this is a "bad thing" for real time data such > as audio/video. > > UDP does not suffer from these delays, also mostly not from buffer-bloat > and is thus much more suited for RTP. Clients must be prepared to handle > out-of-order packets and lost data, etc (ordered queues, Jitter buffers etc) > > Werner > > > Am 20.07.2013 10:42, schrieb Techie Sup: >> I believe these requirement have increased since some ISP does not >> allow commercial VoIP and they filter traffic and block RTP over UDP. >> >> Selvam >> >> On 7/18/13, J Alex Antony Vijay <jfalexvijay at gmail.com> wrote: >>> Shall I know why you want use TCP instead of UDP ? >>> >>> >>> On Tue, Jul 16, 2013 at 9:46 AM, Khoa Pham <onmyway133 at gmail.com> wrote: >>> >>>> Hi, for the SIP transport, pjsip and linphone server do support UDP, TCP >>>> But for Media transport, only UDP is supported. If you 'd like to support >>>> RTP over TCP, please see transport_udp.c in pjmedia project, and make >>>> your >>>> own transport_tcp >>>> >>>> Basically, you will not use UDP socket, but TCP socket for media packet >>>> >>>> >>>> On Thu, Apr 11, 2013 at 11:49 AM, Techie Sup >>>> <techsup0073 at gmail.com>wrote: >>>> >>>>> I too work on similar feature on routing RTP through TCP and please >>>>> share your observations if you come across with a working solution. >>>>> >>>>> Warm Regards >>>>> Selvam >>>>> >>>>> On 4/7/13, gaurav.srivastava2 at agnity.com <gaurav.srivastava2 at agnity.com> >>>>> wrote: >>>>>> >>>>>> Please check http://www.pjsip.org/sip_media_features.htm [1] >>>>>> >>>>>> On Sun, 7 >>>>>> Apr 2013 01:05:49 -0700, Haomiao Huang >>>>>> wrote: >>>>>>> Sorry, what I meant was >>>>>> that the RTP packets were still going out over UDP >>>>>>> and not TCP. So the >>>>>> SIP messaging packets were definitely TCP, but the >>>>>>> media packets were >>>>>> still UDP. >>>>>>> >>>>>>> Any thoughts on why this might be the case? Do I need to do >>>>>> something >>>>>>> separate in PJSIP to make the RTP go out over TCP as well? >>>>>>> >>>>>>> >>>>>> >>>>>>> On Sat, Apr 6, 2013 at 6:08 AM, J Mena wrote: >>>>>>> >>>>>>>> RTP is the protocol >>>>>> used by the application, the rtp packets can be sent >>>>>>>> over different >>>>>> transpors, udp or tcp >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> On Apr 5, 2013, at 10:24 PM, "Haomiao >>>>>> Huang" >>>>>>>> wrote: >>>>>>>> >>>>>>>> Hi, >>>>>>>> I'm trying to get a VOIP app working over >>>>>> 3G. It looks like the RTP >>>>>>>> packets going to and from the phone are not >>>>>> getting through. I would like >>>>>>>> to send media using TCP. How would I go >>>>>> about doing this, and does the >>>>>>>> linphone server support this? I'm using >>>>>> sip.linphone.org for my >>>>>>>> registration. >>>>>>>> >>>>>>>> I've enabled TCP transport >>>>>> on both clients (standard linphone app on iOS >>>>>>>> and pjsua on MacOS). The >>>>>> SIP packets go through on TCP but RTP is still >>>>>>>> being used for the the >>>>>> audio itself. >>>>>>>> >>>>>>>> Any ideas/thoughts on this? Is it the server that's >>>>>> causing this, or do >>>>>>>> I need to do something on the client side? Is this >>>>>> even a good idea? Any >>>>>>>> help would be appreciated! >>>>>>>> -Haomiao >>>>>>>> >>>>>>>> >>>>>>>> >>>>>> _______________________________________________ >>>>>>>> Visit our blog: >>>>>> http://blog.pjsip.org >>>>>>>> >>>>>>>> pjsip mailing list >>>>>>>> pjsip at lists.pjsip.org >>>>>>>> >>>>>> http://lists.pjsip.org/mailman/listinfo/pjsip_lists.pjsip.org >>>>>>>> >>>>>>>> >>>>>>>> >>>>>> _______________________________________________ >>>>>>>> Visit our blog: >>>>>> http://blog.pjsip.org >>>>>>>> >>>>>>>> pjsip mailing list >>>>>>>> pjsip at lists.pjsip.org >>>>>>>> >>>>>> http://lists.pjsip.org/mailman/listinfo/pjsip_lists.pjsip.org >>>>>>>> >>>>>>>> >>>>>> >>>>>> >>>>>> Links: >>>>>> ------ >>>>>> [1] >>>>>> http://www.pjsip.org/sip_media_features.htm >>>>>> >>>>> >>>>> _______________________________________________ >>>>> Visit our blog: http://blog.pjsip.org >>>>> >>>>> pjsip mailing list >>>>> pjsip at lists.pjsip.org >>>>> http://lists.pjsip.org/mailman/listinfo/pjsip_lists.pjsip.org >>>>> >>>> >>>> >>>> >>>> -- >>>> Khoa Pham >>>> HCMC University of Science >>>> www.fantageek.com >>>> >>>> _______________________________________________ >>>> Visit our blog: http://blog.pjsip.org >>>> >>>> pjsip mailing list >>>> pjsip at lists.pjsip.org >>>> http://lists.pjsip.org/mailman/listinfo/pjsip_lists.pjsip.org >>>> >>>> >>> >>> >>> -- >>> >>> Regards, >>> J Alex Antony Vijay. >>> >> >> _______________________________________________ >> Visit our blog: http://blog.pjsip.org >> >> pjsip mailing list >> pjsip at lists.pjsip.org >> http://lists.pjsip.org/mailman/listinfo/pjsip_lists.pjsip.org >> > >
