23.2. Compartments
An application like Session Initiation Protocol (SIP) can group messages that are related. Depending on the signalling protocol, this grouping is done according to how the protocol relates messages: for instance, in SIP, messages are grouped using dialogs or, in cases where there is a configured next-hop address, messages are grouped by the same next-hop address. The application allocates a compressor per compartment and state memory in which to store state information. It also determines when a compartment should be created or destroyed. A compartment is identified uniquely using a compartment identifier.
It is the application's responsibility to determine the compartment identifier for a decompressed message. When an application receives a decompressed message, it determines or creates the compartment for the message and supplies the compartment identifier to the SigComp system.
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