Initially designed for TV broadcasting, DVB standard families have become mature technologies for Internet communications via satellite access networks. A generic encapsulation protocol is therefore required for the forward link, the return link, and for mesh satellite systems. Moreover, because of the cost and the scarcity of resources, this should be as efficient and light as possible. The GSE (Generic Stream Encapsulation) protocol enables efficient transport of any protocol, originally designed for DVB-S2, that is to say on Quasi Error Free (QEF) forward links of satellite systems. This paper addresses limitations in GSE for the return link context and examines the requirements for an encapsulation mechanism for satellite systems using multiple access. This includes the return link but also mesh satellite systems and any satellite systems that uses multiple access. This paper also analyses approaches to derive requirements and provides a first analysis of these requirements.