"Gateway apparatus for facilitating communications using a stateful protocol (e.g., SIP or SIP/SIMPLE protocol). The gateway apparatus includes a plurality of gateway devices and a remote dialog store, wherein each of the plurality of gateway devices comprises export logic for causing dialog information associated with a first received message (e.g., a request or response) to be communicated to the dialog store, and retrieval logic for causing a lookup of the dialog information in response to a second received message, the second received message associated with the first received message. In one example the gateway devices are stateless, thereby relying on the dialog store for validating and routing messages. In another example, the gateway devices are stateful and rely on the dialog store for backup (e.g., if a gateway device crashes). The gateway devices may be configured for receiving and processing messages according to SIP protocol or SIP/SIMPLE protocol."