1.4 Relationship to Protocols and Other Algorithms
The representation of e-mail messages, calendar items, and other Personal Information Manager (PIM) objects by Message objects and their properties is described in [MS-OXOMSG], [MS-OXOCAL], and related specifications.
In contrast, e-mail messages, calendar items, and other PIM objects are represented as textual streams (2) when sent over the Internet using established e-mail protocols. The textual representation of these streams (2) is commonly referred to as RFC2822 format and/or MIME format, as described in [RFC2822], [RFC2045], [RFC2046], [RFC2047], [RFC2048], and [RFC2049].
Conversion between the MIME format and the Message object format is performed in the context of several different protocols. For example:
Servers perform MIME analysis for mail inbound from SMTP.
Servers perform MIME generation for Message objects that are downloaded via the Post Office Protocol - Version 3 (POP3) or the Internet Message Access Protocol - Version 4 (IMAP4). Clients perform MIME generation for messages that are uploaded via IMAP4.
Servers perform MIME analysis for Message objects that are uploaded via IMAP4. Clients perform MIME analysis for Message objects that are downloaded via POP3 or IMAP4.
For conceptual background information and overviews of the relationships and interactions between this and other protocols, see [MS-OXPROTO].