Call-unrelated Interaction between SIP and Parlay/OSA

The paper investigates capabilities of Parlay/OSA (open service access) applications to access to call-unrelated functions, like mobility, user status, terminal capabilities, presence and availability in SIP (Session Initiation Protocol) networks. It addresses means to support Parlay/OSA applications from SIP endpoints in the context of non-INVITE server transactions and client transactions. A mapping between Parlay/OSA interface methods and SIP messages is suggested.