30 Doolan, et al. TDP provides the means for TSRs to distribute, request, and release tag binding information for multiple network layer protocols. TDP also provides means to open, monitor and close TDP sessions and to indicate errors that occur during those sessions. TDP is a two party protocol that runs over a connection oriented transport layer with guaranteed sequential delivery. The means by which a TSR obtains this information is outside the scope of this document.
Configuration is one example.
Once a transport connection has been opened then the TSRs exchange TDP PDUs that encode tag binding information. TDP is symmetrical in that once the transport connection has been opened the peer TSRs may each send and receive TDP PDUs at will. A single TSR may have TDP sessions with multiple other TSRs. Each of these sessions is completely independent of the others. TDP does not require any keepalive notification from the transport, but implements its own keepalive timer.