This chapter contains sections titled:

• Overview of the Presence Service

• Presence Information Data Format

• Rich Presence Information Data Format

• Contact Information in Presence Information Data Format

• Timed Presence Extension to the PIDF

• Presence Capabilities

• Presence Publication

• Presence Subscription and Notification

• Watcher Information

• SIP Exploders and Resource Lists

• XML Configuration Access Protocol

• Presence Optimizations