iSIP: iTIP over SIP and Using iCalendar with SIP

1
iSIP iTIP over SIPand Using iCalendar with SIP

• draft-pessi-calsch-isip-00.txt
• Individual Submission byPekka Pessi, Martti Mela

2
What is SIP?

• SIP is IP telephony signaling protocol
• Based on HTTP, RTSP
• Real-time
• RFC 3261
• Main features
• setting up calls and conferences (RFC 3261)
• instant messages (draft-ietf-sip-message-07.txt)
• event notifications (RFC 3265)

3
What is iCalendar and iTIP?

• iCalendar is calendaring information exchange
  format
• Based on vCalendar
• RFC-822-like syntax
• VEVENT, VFREEBUSY, VTIMEZONE, VTODO, VJOURNAL
• iTIP is an abstract protocol for interaction
  between calendar UAs
• Methods like PUBLISH, REQUEST, REPLY, CANCEL,
  ADD, etc.
• Currently iTIP mapping to mail (iMIP)

4
iCalendar Usage with SIP

• Off-line invitations
• Invitation to future conference (vEvent etc.)
• Describing SIP teleconferences
• Conference roles (chairs, participants, resources
  like conferencing server, etc.)
• Indicating schedule and timezone
• Callee can indicate when he is available
• Notifications for schedule, conference, etc.
• Interested parties can subscribe to a resource,
  receive new iCalendar documents after updates

5
iSIP Mapping iTIP to SIP

• iSIP is very similar to iMIP
• Carry iTIP methods in SIP instant messages
  (SIP MESSAGE requests)
• Allow iTIP PUBLISH methods in any SIP message
• Use MIME, but no Content-Transfer-Encoding
• Use SIP URLs instead of MAILTO URLs
• Because no mapping between MAILTO and SIP
• In some cases, other URL schemes could be used
• tel (telephone numbers) orim (CPIM-compliant
  instant messaging)

6
iSIP and xCal

• Draft proposes using XML iCalendar format with
  SIP
• XML is extensible
• XML is already widely used with SIP applications
• xCal could be included in other XML documents
• but now we are wiser
• extensible XML format require XML schema butxCal
  uses DTD
• Conclusion
• Use RFC2445 format?

7
iSIP and Current CALSCH Work

• No changes to RFC 2445 iCalendar format required
• In future, some iSIP applications (like
  describing a teleconference) may add parameters
  to iCalendar
• No changes to RFC 2446 iTIP required
• No conflict with CAP

8
Open Issues and Future Work

• Does iSIP fit in CALSCH?
• working group item or individual work?
• Submit new draft using standard iCalendard
  format?
• Specify iSIP applications separately
• iCalendar for on-line conferences
• iCalendar notifications