On Mon, 2009-05-11 at 18:32 +0200, Francisco José Méndez Cirera wrote: > A question about the CALL-ID. > > 1. UAC sends an INVITE request to Redirect Server with CALL-ID: abc. > 2. Redirect server sends response "300 Multiples Choices". > 3. UAC makes a pararell search sending three INVITES with CALL-ID: > ¿abc?. > > I dont understand why first INVITE and three last INVITES have the same > CALL-ID...
The three INVITEs generated in step 3 are considered to be forks of the original INVITE from step 1. The reason why this is the best way to organize the operation is that the UAC only wishes to establish one dialog, with whichever of the INVITEs receives a successful response. Since all 4 INVITEs have the same call-id, if (through more forking downstream), one UAS receives two INVITEs derived from them, it can responds to the second INVITE with 482, thus avoiding having the UAS present two copies of the same logical call to its user. Dale _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
