A method for identifying alternative end-to-end media paths through Internet protocol realms using substitute session description protocol parameters is disclosed. The method includes receiving a session description protocol offer, including a list of internet protocol realms. The list may include any number of previously traversed through internet protocol realms and/or secondary Internet protocol realms. The method continues with determining the outgoing Internet protocol realm for a media path based on unspecified signaling criteria. Finally, the method includes that if the outgoing Internet protocol realm to be traversed through is on the list of previously traversed through and/or secondary Internet protocol realms, bypassing at least one border gateway associated with the incoming and previously traversed through Internet protocol realms. The system implementing a method for identifying optimal end-to-end media paths and Internet protocol multimedia subsystems includes a list of internet protocol realm instances and an application level gateway configured to receive a session description protocol offer having connection information and port information, and a procedure to determine that if the outgoing Internet protocol realm that the media path may traverse through is on the list of instances, the media path connection information and port information is substituted to facilitate border gateway bypassing.