Using TDS tunnelling

jConnect uses TDS to communicate with database servers. HTTP-tunnelled TDS is useful for forwarding requests. Requests from a client to a back-end server that go through the gateway contain TDS in the body of the request. The request header indicates the length of the TDS included in the request packet.

TDS is a connection-oriented protocol, whereas HTTP is not. To support security features such as encryption for Internet applications, jConnect uses a TDS-tunnelling servlet to maintain a logical connection across HTTP requests. The servlet generates a session ID during the initial login request, and the session ID is included in the header of every subsequent request. Using session IDs lets you identify active sessions and even resume a session, as long as the servlet has an open connection using that specific session ID.

The logical connection provided by the TDS-tunnelling servlet enables jConnect to support encrypted communication between two systems; for example, a jConnect client with the CONNECT_PROTOCOL connection property set to “https” can connect to a Web server running the TDS-tunnelling servlet.