Creating and using a SipMessage

Table of Contents Components stuff Computing 2543 transaction ids. Variants

Components

Headers

Uris

Bodies

Parameters

Extension Headers

Extension Parameters

stuff

Computing 2543 transaction ids.

Transaction ids are used to map a message to the state of its transaction.

3261 uses assigned transaction ids carried in the branch parameter of the Via. 2543 uses a transaction id that is computed from the message.

The 2543 transaction is a hash of:

• top Via
  • protocolName
  • protocolVersion
  • transport
  • sentHost
  • sentPort
  • commutativeParameterHash (not sensitive to the order of the paramters)
• From tag
• To tag (if non-invite request)
• Call-Id
• method (INVITE if ACK or CANCEL)

Once computed, the 2543 transaction id is cached on the message.

Variants

SipFrag

Embedded Headers