| Summary: |
A key part of the behavior of the Session Initiation Protocol
(SIP) is that SIP proxies rewrite the Request-URI as a request moves
throughout the network. Over the years, experience has shown this to
be problematic. It makes it difficult to use Request URI for service
invocation, complicates emergency services, makes it more complex to
support aliases, and so on. Architecturally, it confounds the concepts
of address and route. This document proposes to change this through a
new mechanism called UA loose routing.
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