A method comprising: receiving, by a gateway control function of a gateway device, a session initiation protocol invite message for a first media composition from a second network domain, said second network domain supporting downgrading of media compositions; and characterized by comprising: initiating, by said gateway control function, establishment of a first session with the first media composition in a first leg of a first network domain, by transmitting a first call set-up request for said first media composition to said first network domain in response to the receipt of said session initiation protocol invite message; identifying, by said gateway control function, a rejection message from said first network domain, said rejection message indicating that said first call set-up request for said first media composition in said first leg is rejected by said first network domain; in response to the identifying, releasing said first session and setting up a second session for a downgraded second media composition in said first network domain by said gateway function, by transmitting a second call set-up request from said gateway function to said first network domain via said first leg; and updating, by said gateway control function, a call or session in a second leg of said second network domain by said gateway function to match said downgraded media composition being established in said first leg. receiving, by a gateway control function of a gateway device, a session initiation protocol invite message for a first media composition from a second network domain, said second network domain supporting downgrading of media compositions; and characterized by comprising: initiating, by said gateway control function, establishment of a first session with the first media composition in a first leg of a first network domain, by transmitting a first call set-up request for said first media composition to said first network domain in response to the receipt of said session initiation protocol invite message; identifying, by said gateway control function, a rejection message from said first network domain, said rejection message indicating that said first call set-up request for said first media composition in said first leg is rejected by said first network domain; in response to the identifying, releasing said first session and setting up a second session for a downgraded second media composition in said first network domain by said gateway function, by transmitting a second call set-up request from said gateway function to said first network domain via said first leg; and updating, by said gateway control function, a call or session in a second leg of said second network domain by said gateway function to match said downgraded media composition being established in said first leg. initiating, by said gateway control function, establishment of a first session with the first media composition in a first leg of a first network domain, by transmitting a first call set-up request for said first media composition to said first network domain in response to the receipt of said session initiation protocol invite message; identifying, by said gateway control function, a rejection message from said first network domain, said rejection message indicating that said first call set-up request for said first media composition in said first leg is rejected by said first network domain; in response to the identifying, releasing said first session and setting up a second session for a downgraded second media composition in said first network domain by said gateway function, by transmitting a second call set-up request from said gateway function to said first network domain via said first leg; and updating, by said gateway control function, a call or session in a second leg of said second network domain by said gateway function to match said downgraded media composition being established in said first leg.