This Recommendation specifies the Signalling Transport Converter sublayer directly on top of SSCOP (which specifies the peer-to-peer protocol for the transfer of information and control between any pair of SSCOP entities). Operation of SSCOP in a point-to-point environment is specified in ITU-T 4.2110 [2]. In a multi-link or connectionless environment, its operation (SSCOPMCE) is specified in ITU-T 4.2111 [3]. Since the service provided by either of these Recommendations is the same, this Recommendation only describes the actions in terms of ITU-T 4.21 10 for clarity of expression. The Signalling Transport Converter on SSCOP can be deployed on any protocol stack that supports SSCOP (see 5.1). This Recommendation covers the specification of the sublayer structure, the PDU structures of the Signalling Transport Converter sublayer, and the mechanisms for the provision of the Generic Signalling Transport Service.