Lyndon,
I agree that IMAP has no "notification scenarios". The main scenario of IMAP is mailbox and message access.
However, in the messaging world there IS a need for "notification scenarios". This is why SNAP and other protocols are proposed. There are actual (shipping) products and services that issue notifications to end users based on the contents of their e-mail mailbox.
Since IMAP is the only practical standard for accessesing messages in a mailbox, these scenarios do use IMAP as part of their sequence. In the example I gave, the scenario is to "directly-access" a specific message (rather than forcing the user to select a messasge from a list in the mailbox).
UIDs are not firstly introduced by the "notification scenario". They are part of the IMAP protocol for a long time and are supported in many (if not all?) commands that reference a message or a message set.
UIDs are used by E-mail clients as some form of "long-term" id of a message in a mailbox, which persists across IMAP sessions. As far as I know, E-mail clients that cache messages use UIDs to synchonize between their local cache and the remote IMAP mailbox.
So, if UIDs exist and are used for "long-term" message identification (across IMAP sessions) - why can't the same mechanism be used in a "notification scenario"?
I did not understand your last sentence - "The server itself decides if the request is valid, let alone if it is a reasonable idea."
Did I suggest something else?
Best Regards,
Ari Erev
-----Original Message-----
From: Lyndon Nerenberg [mailto:lyndon@xxxxxxxxxxxxxxxxxxxx]
Sent: Thursday, March 07, 2002 10:13 AM
To: Erev, Ari; 'ietf-imap-voice@xxxxxxx'
Subject: Re: UID for IMAP Channel?
> > When Notification scenarios are considered, it may be that the client gets
> > some indication about a specific message for which it then issues a CHANNEL
> > command (i.e, the client did not necessarily received all sequence numbers
> > in the mailbox before issuing the CHANNEL command, so it can't map between
> > UID and sequence number).
IMAP has no "notification scenarios" as this describes. It's a common
misconception that UIDs have an equivalence map to IMAP sequence
numbers. There are no asynchronous events that map between the two. A
client that issues an IMAP CHANNEL request simply asks the server to
perform a task on its behalf. The server itself decides if the request
is valid, let alone if it is a reasonable idea.
--lyndon