The PUBLISH Method

1
The PUBLISH Method

• Draft-olson-sip-publish-00

2
Overview

• A general purpose mechanism for publishing event
  state
• First application is presence publication
• Based on model for presence composition
• Defines new PUBLISH method
• New PType, PStream, PState Headers

3
A model for presence composition

• Event state is published to a slot identified
  by a token carried in the PType header. The slot
  identifies the context of the published data
• Publishing devices are distinguished by a unique
  identifier carried in the PStream header
• One or more devices can publish to the same slot
• Event state is soft-state with an expiration
  value carried in the PState header

4
A model for presence composition
Presence Compositor
A third party publishing on behalf of the user
using a well-known Ptype (e.g. geoloc)
Share the same slot or PType Differentiated by
PStream
5
Example PUBLISH message

• PUBLISH sippresentity_at_domain.com SIP/2.0
• Via SIP/2.0/UDP pua.domain.combranchz9hG4bK652h
  sge
• To ltsippresentity_at_domain.comgt
• From ltsippresentity_at_domain.comgttag1234wxyz
• Call-ID 12345678_at_pua.domain.com
• CSeq 3242 PUBLISH
• Expires 3600
• Event presence
• PType mobile
• PStream f81d4fae-7dec-11d0-a765-00a0c91e6bf6_at_pua.
  domain.com
• Content-Type application/cpim-pidfxml
• Content-Length ...
• lt?xml version"1.0" encoding"UTF-8"?gt
• ltpresence xmlns"urnietfparamsxmlnscpim-pidf"
  entity"prespresentity_at_domain.com"gt
• lttuple id"mobile-phone"gt
• ltstatusgt ltbasicgtclosedlt/basicgt lt/statusgt
• lt/tuplegt
• lt/presencegt

6
Open Issues

• Do we attempt to solve the CPL problem with the
  same model/mechanism?
• Is the slot concept the right way to go?
• Do we need to standardize the PType tokens?
• Should PType require IANA registration?
• Replace PState with Expires header?