Thank you Hadriel for your answer, very interesting. I CC the list now as I forgot to include it in my previous email.
Regards, Pascal On Thu, Apr 10, 2008 at 3:47 PM, Hadriel Kaplan <[EMAIL PROTECTED]> wrote: > Inline… > > > ------------------------------ > > *From:* Pascal Maugeri [mailto:[EMAIL PROTECTED] > *Sent:* Thursday, April 10, 2008 4:16 AM > *To:* Hadriel Kaplan > *Subject:* Re: [Sip-implementors] SIP ALG and NAT keepalive, solutions for > incoming calls? > > > > Regarding your comment about OPTIONS vs REGISTER, I tend to agree with you > but what is your opinion regarding the load that the clients will add to the > registrar ? > > No not in typical deployments, where there's a "proxy" or SBC between the > clients and registrar. Those boxes do certain things such that the > registrars only get the 3600-second registers as they expect (or whatever > longer expires time they wanted). > > > > Let's imagine thousands of clients refreshing, every 20s their > registration in the registrar, is that a significant load for the registrar > ? > > Nope, see above. J > > > > BTW, using REGISTER has the advantage over OPTIONS that the server can > detect if the client is behind a NAT and force re-registration every few > seconds with a small value of Expires in REGISTER OK. > > Yes, that's one of the primary reasons it's used, but it also has > failure-detection and recovery advantages that Options doesn't have. > > > > Can you explain what you meant with "double-crlf for TCP" ? > > See draft-ietf-sip-outbound-13.txt ( > http://tools.ietf.org/html/draft-ietf-sip-outbound-13). The "keepalive" > to keep a SIP/TCP or SIP/TLS connection open is sending two CRLF's as a > "ping", and getting back one CRLF set as a "pong". > > > > This is for the binding opened for SIP. Then regarding the ports needed > for RTP, what do you recommend to keep the binding opened in NAT devices > ? Sending empty UDP packets ? > > Most SIP communications today is bidirectional voice/video, so the RTP > packets going the other way do it. But when people are muted or for > uni-directional, most phones send either silence indication (if the codec > has that), or no-op RTP packets, or STUN packets. > > -hadriel > > > _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
