1. First, I am glad to see more people support of "Rollback" and the concept of "part of re-INVITE transaction"(nested-transaction).
2. Your example using e2e resource reservation, then the Path(from the Offerer) should after first Offer/Answer. Because the destination of the Path is the IP address in the Answer.
3. Order problem(or say racing conditon) is solved in my draft.
4. The current focus of the topic is atomicity's semantic of Re-INVITE and UPDATE. And this is also discussed in my newest version of the draft.
As you are interested in the concept of "part of re-INVITE transaction", I am waiting for your further talk about this topic.
Newest version of the draft: http://www.ietf.org/internet-drafts/draft-gaoyang-sipping-session-state-criterion-03.txt
| "Anton Tveretin"
<fas_vm@xxxxxxxxxxxx>
2009-04-09 02:23 |
|
Hi,
First, preconditions could (and IMHO SHOULD) be satisfied before re-INVITE.
So anyway, they will be rolled back explicitly if re-INVITE fails. IMHO
normal diagram for re-INVITE would look like this, am I right? (Adding a new
stream)
-->RSVP:Path
<--RSVP:Resv
-->RSVP:ResvConf
-->SIP:INVITE(offer);
<--SIP:180(no SDP)
<--RSVP:Path
-->SIP:PRACK
<--SIP:200 PRACK
-->RSVP:Resv
<--RSVP:ResvConf
---waiting for user to accept or reject new media---
<--SIP:200 INVITE(answer)
-->SIP:ACK
I mean, 1xx responses to re-INVITE should not contain SDP, as there is no
reason.
Second, UPDATE easily goes into race conditions with re-INVITE. Recall Gao's
diagram:
-->re-INVITE (F1)
<--1xx (F2)
<--UPDATE (F3)
F2 and F3 may be delivered out of order. So there will be no way to tell
whether F1 or F3 came out first. This is also true even both re-INVITE and
UPDATE were sent by the same UA. Only SDP versioning helps.
So UPDATE is not a part of re-INVITE transaction if it contained no SDP.
IMO everything that clearly is a part of re-INVITE transaction, must be
rolled back.
Consider the following:
-->re-INVITE(offer1)
<--180(answer1)
-->PRACK
<--200 PRACK
-->UPDATE(offer2)
<--200 UPDATE(answer2)
<--603 INVITE
-->ACK
Still, UA at left might not commited the second O/A pair (if responses to
the re-INVITE and UPDATE were re-ordered).
Regards
-------------------------------------------------------- ZTE Information Security Notice: The information contained in this mail is solely property of the sender's organization. This mail communication is confidential. Recipients named above are obligated to maintain secrecy and are not permitted to disclose the contents of this communication to others. 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. If you have received this email in error please notify the originator of the message. Any views expressed in this message are those of the individual sender. This message has been scanned for viruses and Spam by ZTE Anti-Spam system.
_______________________________________________ Sipping mailing list https://www.ietf.org/mailman/listinfo/sipping This list is for NEW development of the application of SIP Use sip-implementors@xxxxxxxxxxxxxxx for questions on current sip Use sip@xxxxxxxx for new developments of core SIP
