This document summarizes the SIP signaling flow for establishing a mobile originating call with QoS in an IMS network. It shows the steps for: 1) P-CSCF discovery via DHCP/DNS query after PDP context activation 2) The UE sending an INVITE message to the P-CSCF which is then forwarded to the S-CSCF to trigger application servers 3) The S-CSCF authorizing QoS resources after receiving a 183 Session Progress response 4) The call being established with an ACK and the exchange of media 5) The call being released with a BYE message which triggers removal of QoS reservations.