On Sun, Feb 3, 2013 at 12:46 PM, Fabio Pietrosanti (naif) <li...@infosecurity.ch> wrote: > ... > To work over high latency (and tipically also low-bandwidth) with > reliable transport (like TCP/Tor) you need to use those multimedia strategy: > - setup a large static jitter buffer (you define the added artificial > latency of the call to compensate variable latency) > - reduce transport protocol overhead by setting a large "packetization time" > - detect retransmission behaviours, in that case apply small TX cutting > (transmission)
presence and connection signaling is a problem too; also requiring customization / enhancements to the signalling and transport layers around these mechanisms, in addition to the voice transport and implementations details you mention above (which also apply to multi-media, were you to extend the ZRTP / Tor'ified streams to video and extended media). large static jitter buffers also need more help, as a Tor circuit has a much larger total delay in addition to jitter variance. smarter dynamic jitter buffers, noise cancelation / silence optimization / other expensive processing options are useful and applicable, as anything running a Tor client has plenty of processing power for voice of any complexity. regarding the directory and signalling, i would love to test: - petname or distributed directory (namecoin) for people to hidden server address(es) - custom Tor controller to establish and advertise multiple hidden service endpoints concurrently via different rendz. - custom SIP/signalling extensions to advertise and register via ordered hidden svz addresses (maybe just transparent DNS with multiple peers in RRs?) - long-lived-ports modified for circuit availability, consistency over absolute duration? with the transport and voice processing improvements discussed above. > With such approach you can avoid "PTT" and even if the communication > will sounds like an old analog satellite connection, it works. PTT is orthogonal to the transport question, perhaps limited to some context like group / conference / broadcast idioms. i agree it may not be necessary. best regards, _______________________________________________ tor-talk mailing list tor-talk@lists.torproject.org https://lists.torproject.org/cgi-bin/mailman/listinfo/tor-talk
