A method of compressing messages for transmission from a network device (202a, 524) to another device (524, 202a), the method comprising implementing at the network device the following steps: generating an uncompressed message for transmission to the another device via a network; generating a compressed version of the message, having a reduced message size, by applying a compression function to the uncompressed message; determining the reduced message size of the compressed version; comparing the reduced message size to a maximum transport packet size of a preferred one of a plurality of transport protocols; characterized in that the method comprises: if the reduced message size exceeds the maximum transport packet size of the preferred transport protocol, encapsulating the uncompressed or the compressed version of the message into one or more transport packets according to a non-preferred one of the transport protocols, and transmitting the one or more transport packets to the another device according to the non-preferred transport protocol via the network, the non-preferred transport protocol being a reliable transport protocol; and if the size of the compressed message does not exceed the maximum transport packet size of the preferred transport protocol, encapsulating the compressed version of the message into a single transport packet according to the preferred transport protocol, and transmitting the transport packet to the another device according to the preferred transport protocol via the network, the preferred transport protocol being an unreliable transport protocol according to which the establishment of the communication event based on said session is initially attempted. generating an uncompressed message for transmission to the another device via a network; generating a compressed version of the message, having a reduced message size, by applying a compression function to the uncompressed message; determining the reduced message size of the compressed version; comparing the reduced message size to a maximum transport packet size of a preferred one of a plurality of transport protocols; characterized in that the method comprises: if the reduced message size exceeds the maximum transport packet size of the preferred transport protocol, encapsulating the uncompressed or the compressed version of the message into one or more transport packets according to a non-preferred one of the transport protocols, and transmitting the one or more transport packets to the another device according to the non-preferred transport protocol via the network, the non-preferred transport protocol being a reliable transport protocol; and if the size of the compressed message does not exceed the maximum transport packet size of the preferred transport protocol, encapsulating the compressed version of the message into a single transport packet according to the preferred transport protocol, and transmitting the transport packet to the another device according to the preferred transport protocol via the network, the preferred transport protocol being an unreliable transport protocol according to which the establishment of the communication event based on said session is initially attempted. if the reduced message size exceeds the maximum transport packet size of the preferred transport protocol, encapsulating the uncompressed or the compressed version of the message into one or more transport packets according to a non-preferred one of the transport protocols, and transmitting the one or more transport packets to the another device according to the non-preferred transport protocol via the network, the non-preferred transport protocol being a reliable transport protocol; and if the size of the compressed message does not exceed the maximum transport packet size of the preferred transport protocol, encapsulating the compressed version of the message into a single transport packet according to the preferred transport protocol, and transmitting the transport packet to the another device according to the preferred transport protocol via the network, the preferred transport protocol being an unreliable transport protocol according to which the establishment of the communication event based on said session is initially attempted.