Partial-order transport service for multimedia and other applications

Investigates a partial-order connection (POC) service/protocol. Unlike classic transport services that deliver objects either in the exact order transmitted or according to no particular order, POC provides a partial-order service, i.e. a service that requires some, but not all objects to be received in the order transmitted. Two versions of POC are proposed: reliable, which requires that all transmitted objects are eventually delivered, and unreliable, which permits the service to lose a subset of the objects. In the unreliable version, objects are more finely categorized into one of three reliability classes depending on their temporal value. Two metrics based on e_i(P), the number of linear extensions of partial-order P in the presence of i lost objects, are proposed as complexity measures of different combinations of partial order and reliability. Formulae for calculating e_i(P) are derived when P is series-parallel. A formal specification of a POC protocol, written in Estelle, is presented and discussed. This specification was designed and validated using formal description tools and provides a basis for future implementations