Abstract: In one embodiment a communication client, includes at least one sending interface to send a signaling message in accordance with the SIP protocol, towards a first interface of a communication server. The client and server are connected by a communication network. The communication client is suitable for inserting an indication within the signaling message regarding the interface for the communication server to use to send its response signaling message.

Abstract: Communication system (S) able to exchange SIP signaling messages, with a communication network (N), containing multiple servers (S1, S2, S3 . . . Sn) to handle incoming messages (ms) and generate outgoing messages and a load distribution device (LB) to route an incoming message to a particular server according to load distribution rules (R, Raff). The servers have means to include in the outgoing messages a marker representing at least itself, and the load distribution rules of the load distribution device contain rules (R) so that, when a marker is included in an incoming message, it can be routed to the server corresponding to the marker.

Abstract: SIP Proxy comprising a loop detection mechanism (LD) consisting of calculating a signature for an incoming signalling message from a set of parameters for said incoming signalling message, and detecting a loop by comparing this signature with values inserted in a particular parameter of the incoming signalling message, characterised in that said sending means (EMS) insert the signature in the particular parameter of the outgoing signalling message (ms) corresponding to the incoming signalling message (me). It is applicable to IMS (“Internet Multimedia Subsystem”) type communication architectures.