<HTML><BODY style="word-wrap: break-word; -khtml-nbsp-mode: space; -khtml-line-break: after-white-space; ">I don't see why SCTP would fare one iota different than TCP. In context, they have essentially equivalent message exchange. SIP on UDP would do it in less RTTs, in that there would be no SYN/SYN-ACK or FIN/FIN-ACK. I think the real difference there is debateable, though.<DIV><BR class="khtml-block-placeholder"></DIV><DIV>Allocating excess capacity to a signaling channel and putting SIP into it basically allows SIP to bypass queues that form around file transfers. Personally, I think this is a good thing, and RFC 4542 supports it.<DIV><BR class="khtml-block-placeholder"></DIV><DIV><BR><DIV><DIV>On May 15, 2006, at 11:13 PM, weigengyu wrote:</DIV><BR class="Apple-interchange-newline"><BLOCKQUOTE type="cite"><SPAN class="Apple-style-span" style="border-collapse: separate; border-spacing: 0px 0px; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; text-align: auto; -khtml-text-decorations-in-effect: none; text-indent: 0px; -apple-text-size-adjust: auto; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px; "><DIV><FONT size="2"><SPAN class="Apple-style-span" style="font-size: 10px; ">Hi,</SPAN></FONT></DIV><DIV><FONT size="2"></FONT> </DIV><DIV><FONT size="2"><SPAN class="Apple-style-span" style="font-size: 10px; ">Can anyone give an answer to my question?</SPAN></FONT></DIV><DIV><FONT size="2"></FONT> </DIV><DIV><FONT size="2"><SPAN class="Apple-style-span" style="font-size: 10px; ">1. SIP will be the signaling protocol for IMS in 3GPP,and SIP can be over TCP, UDP, or SCTP;</SPAN></FONT></DIV><DIV><FONT size="2"><SPAN class="Apple-style-span" style="font-size: 10px; ">2. For SIP over TCP as signaling transfer, are there any analysis model for the performance evaluation?</SPAN></FONT></DIV><DIV><FONT size="2"><SPAN class="Apple-style-span" style="font-size: 10px; ">3. Somebody told me that there is no problem if you allocate enough bandwidth to signaling channel.</SPAN></FONT></DIV><DIV><FONT size="2"><SPAN class="Apple-style-span" style="font-size: 10px; "> (the enough bandwidth in engineering design may be 10% of total transmission line capacity)</SPAN></FONT> </DIV><DIV><FONT size="2"><SPAN class="Apple-style-span" style="font-size: 10px; "> So, is there any measured data to support the above design.</SPAN></FONT></DIV><DIV><FONT size="2"></FONT> </DIV><DIV><FONT size="2"><SPAN class="Apple-style-span" style="font-size: 10px; ">4. Could you get better performance by SIP over SCTP than SIP over TCP for signaling transfer?</SPAN></FONT></DIV><DIV><FONT size="2"></FONT> </DIV><DIV><FONT size="2"><SPAN class="Apple-style-span" style="font-size: 10px; ">Gengyu</SPAN></FONT></DIV><BR class="Apple-interchange-newline"></SPAN></BLOCKQUOTE></DIV><BR></DIV></DIV></BODY></HTML>