1. iSIP: iTIP over SIP and Using iCalendar with SIP
draft-pessi-calsch-isip-00.txt
Individual Submission by Pekka 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) or im: (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 but xCal 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