This working group focuses on the application of the Session Initiation Protocol (SIP, RFC 3261) to the suite of services collectively known as instant messaging and presence (IMP). The IETF has committed to producing an interoperable standard for these services compliant to the requirements for IM outlined in RFC 2779 (including the security and privacy requirements there) and in the Common Presence and Instant Messaging (CPIM) specification, developed within the IMPP working group. As the most common services for which SIP is used share quite a bit in common with IMP, the adaptation of SIP to IMP seems a natural choice given the widespread support for (and relative maturity of) the SIP standard. The primary work of this group will be to generate: 1. A proposed standard SIP extension documenting the transport of Instant Messages in SIP, compliant to the requirements for IM outlined in RFC 2779, CPIM and in BCP 41 (so that the transport implications of the extension with respect to network congestion are considered in the design). 2. A proposed standard SIP event package and any related protocol mechanisms used to support presence, compliant to the requirements for presence outlined in RFC 2779 and CPIM. 3. An architecture for the implementation of a traditional buddylist-based instant messaging and presence application with SIP. Included might be new mechanisms for message confirmation delivery, indications for when a party is in the process of typing a message, secure buddylist manipulation operations, and the extension of the CPIM presence format to describe typical IM states. Each of these mechanisms will be consistent with a SIP-based architecture, as well as meeting the constraints otherwise described in this charter. All SIMPLE proposals fulfilling these goals must document the mappings of their operation to CPIM. Any SIP extensions proposed in the course of this development will, after a last call process, be transferred to the SIP WG for consideration as formal SIP extensions. The working group will work within the framework for presence and IM described in RFC 2778. The extensions it defines must also be compliant with the SIP processes for extensions. The group cannot modify baseline SIP behavior or define a new version of SIP for IM and presence. If the group determines that any capabilities requiring an extension to SIP are needed, the group will seek to define such extensions within the SIP working group, and then use them here. The working group will operate in close cooperation with the IMPP working group, which will be completing CPIM in parallel. The working group will also cooperate with any other groups defined to standardize other presence and IM systems, to ensure maximum sharing of information and avoid reinvention of the wheel. The working group will cooperate with the SIP working group, soliciting reviews to ensure its extensions meet SIPs requirements. The working group will also collaborate with the SIP WG to ensure consistent operation of the SUBSCRIBE and NOTIFY methods across the other applications being defined for its use.