Venkat: Comments inline with [SSS]
Somesh * Please do not take print out of this e-mail unless its absolutely necessary * -----Original Message----- From: [email protected] on behalf of VYANKTESH TADKOD Sent: Tue 2/3/2009 2:40 PM To: [email protected] Subject: [Sip-implementors] Question on Branch parameter usage Hi All, I am straightaway jumping to the question here If there are 2 UA (UAC's) talking to another UA (UAS) ... a> can both the UAC's use the same branch parameter value in the via header at the same time across different SIP message(s) ? I have a situation where one UA is sending a branch value say A in the top via header of the BYE message and after let say 3-4 sec later I have a INVITE message from another UA with the top via header having the same branch value A. Is this correct? Pls advice. [SSS] Usually the branch parameter prefered to be unique over space and time to prevent conflicts later. So, in most of the implementations its different and unique. In your situation since there is no uniqueness of branch ( both UA's are sending same branch; one in BYE and one in INVITE), I would still process the INVITE because, with BYE the earlier dialog was terminated. Even if I match a transaction to BYE which is in TERMINATED state, I would still entertain receiving the INVITE and processing it. b> In the same context, if the BYE is received by a UA, should the UA (underlying SIP stack) respond to BYE and immediately remove it from transaction table? I see that few of the SIP stack remove the transaction immediately from the transaction table and few of the stack keep the transaction for few secs (~32 sec) before they remove it from the transaction table. Few questions 1> What is purpose of keeping the transaction data (i.e branch ID) in transaction table once the BYE is processed? [SSS] If you have responded to BYE, say 200 OK over UDP, then you would keep the keep the transaction around just to see if any re-transmissions happen because of UDP or network problem and respond with last sent message so that it would not go until the dialog. 2> Is there any standard which mentions about how long it should keep the transaction in the table after it has processed BYE? [SSS] Typically its 64*T1 as per RFC 3261 Thanks and Regards -venkat _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors EMAIL DISCLAIMER : This email and any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom they are addressed. Any unauthorised distribution or copying is strictly prohibited. If you receive this transmission in error, please notify the sender by reply email and then destroy the message. Opinions, conclusions and other information in this message that do not relate to official business of Mascon shall be understood to be neither given nor endorsed by Mascon. Any information contained in this email, when addressed to Mascon clients is subject to the terms and conditions in governing client contract. Whilst Mascon takes steps to prevent the transmission of viruses via e-mail, we can not guarantee that any email or attachment is free from computer viruses and you are strongly advised to undertake your own anti-virus precautions. Mascon grants no warranties regarding performance, use or quality of any e-mail or attachment and undertakes no liability for loss or damage, howsoever caused. _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
