IMS S3-3a. SIP PRACK request (UE1 to UE2): from MGCF1 to S-CSCF2

Tech-invite 3GPPspace IETFspace

SIP ↠ Examples Grammars Presence ⇾ Main Services Transaction Dialog IMS

TS 24.228 – §7.2.4 – §7.3.5 – §7.4.3

IMS S3 signalling flow - Session Initiation: Origination in CS Network, and Mobile termination in home network - IMS S3-3a. SIP PRACK request (UE1 to UE2): from MGCF1 to S-CSCF2

MGCF sends a PRACK request without SDP, because there is not another set of codecs to the original SDP offer.
Via: Takes the value of either the IP address or FQDN of the originating MGCF.
Cseq: Takes a higher value than that in the previous request.