The HELD BEEP Protocol Binding

The HTTP binding for HELD is constrained to a single request-response exchange. If a particular location recipient requires location information over time, or for multiple targets, a more permanent association could provide benefits. HTTP pipelining permits the queuing of requests on a single connection, but this suffers from head-of-queue blocking and is limited in its flexibility. BEEP provides a protocol framework that is based on an established TCP (orTLS) connection between two hosts that can be reused. BEEP also includes message identifiers, which means that multiple requests can be interleaved and processed independently.

The HELD BEEP binding is limited to trusted party queries from nodes such as proxy servers and call routing functions. This is because it does not support queries to location URIs; there is no generic BEEP URI type, and no HELD-BEEP-specific URI type has been defined.

To ensure confidentiality, connections should be established using TLS with mutual authentication. The following cipher suites are recommended: TLS_RSA_WITH_AES_ 256_CBC_SHA, TLS_RSA_WITH_AES_128_CBC_SHA.

The MIME types of requests and responses are the same as for the HTTP binding. The function served by the HTTP Expires header is replicated by an identical entity-header that is included with a BEEP frame.

The HELD BEEP binding does not include a default request. All requests must include XML content.

The HELD profile is identified by the URN:

 http://sitacs.uow.edu.au/ns/location/held/beep 

Following the guidelines of Reference 4, Table D.1 summarizes the HELD profile.

Table D.1: The Held Beep Profile Summary

Registration Item	Value
Profile Identification	http://sitacs.uow.edu.au/ns/location/held/beep
Messages exchanged during Channel Creation	(None)
Messages starting one-to-one exchanges	held:locationRequest, held:createContext, held: updateContext
Messages in positive replies	pidf:presence, held:contextResponse
Messages in negative replies	held:error
Messages in one-to-many exchanges	(None)
Message syntax	See Reference 5 and Appendix B.
Message semantics	See Reference 5.
Contact information	The authors of this book.