TKK NEC Nokia Siemens Networks Univ. of Karlsruhe Signaling layer protocols in the NSIS working group may rely on GIST to handle authorization. Still, the signaling layer protocol itself may require separate authorization to be performed when a node receives a request for a certain kind of service or resources. This draft presents a generic model and object formats for session authorization within the NSIS Signaling Layer Protocols. The goal of session authorization is to allow the exchange of information between network elements in order to authorize the use of resources for a service and to coordinate actions between the signaling and transport planes.