Hello,
Still no responce at all to my idea of putting an MRA agent between the two
message stores.
MRA (Mail Retrieval Agent)
Is it so far fetched?
Or is it because the draft equals mail handling system (MHS) with SMTP?
(POP3, IMAP, ODMR and other Pull mechanisms do not really count)
Here are two reasons to split the rMUA up in a MRA and rMUA:
Architectionaly the rMUA is between the user and the localMS and the MRA
between the server ans the local message stores.
An other reason is that if you have an MRA you can describe POP3-ODMR-or
SMTP(ETRN)-mailservers as consisting of
MRA-MDA-MS systems.
So following some new texts.
4.6 sMS server Message Store
The sMS is where SMTP does final delivery
it is a message store as mentioned in RFC2821 section 2.3.3.
This store SHOULD always be accessible (local) to the MDA.
(NOT to the rMUA)
It is the end of the SMTP store-and-forward transfer.
4.7 Message Retrieval Agent (MRA) and lMS
The MRA and the lMS are to overcome tht what is called "the lacking of the
resource known as "connectivity". (copied from RFC 1939 section 1
introduction)
where this resource is not lacking (webmail and other always connected systems)
the MRA and the lMS are not needed.
The MRA works on request of the receiving User, or automaticly by the MUA.
The MRA links the computer to the sMS and collects the messages.
There is no need for a connection between the MRA and the rMS if the MRA is not
retrieving messages
The MRA message retrieval agent retrieves the mail from the server Message
Store and stores it on the local machine of the receiver-user. this can be done
by download protocols like (pop3) (ODMR) (SMTP-ETRN) or with synchronising
protocols like (IMAP4)
While downloading in general implies that the message in the sMS is deleted.
With synchronising the message is kept in the server message store.
4.8 local message store lMS
The lMS is the final store for the message.
This message store resides in the local computer of the MUA. and is available
to the user for manipulating, reading etc.
4.9 receiver Mail User Agent rMUA
(text copied from 4.2)
The Recipient-side rMUA works on behalf of the end-user Recipient to process
received mail. This includes generating user-level return control messages,
display and disposition of the received message, and closing or expanding
the user communication loop, by initiating replies and forwarding new
messages.
figure 5 should be changed to
. +------+ | |
. | +-----------------------+ |
. | MDA | |
. | |<--------------------+ |
. +-+--+-+ | |
. V (local) | |
. +------+ /+===+===+\ |
. | sMS | || sieve || |
. +-+--+-+ \+=======+/ |
. | | {pop, imap ,odmr) ^ |
. | V | |
. | +------+ | |
. | | MRA | | |
. | +------+ | |
. | V (local) | |
. | +------+ | |
. | | uMS | | |
. | +--+---+ | |
. V V {local) | |
. +------+ | |
. | +---------------------+ |
..............>| rMUA | |
| +-------------------------------+
+------+
(notice how nice local links are only one V long.
Maybe it is even nicer it link local parts together then it becomes:
. +------+ | |
. | +-----------------------+ |
. | MDA | |
. | |<---------------------+ |
. +------+ /+===+===+\ |
. | sMS | || sieve || |
. +-+--+-+ \+=======+/ |
. | | (pop, imap ,odmr) ^ |
| | (ODMR SMTP-ETRN) | |
. | V | |
. | +------+ | |
. | | MRA | | |
. | +------+ | |
. V | lMS | | |
. +--+--+---+ | |
. | +------------------+ |
..............>| rMUA | |
| +---------------------------+
+---------+
references
POP3 [RFC1939]
SMTP-ETRN [RFC1985]
ODMR [RFC2645]
IMAP [RFC3501]
note:
In this description the MRA can both use
Host to Client protocols (POP3 and IMAP) as
Host to Host protocols (ODMR and SMTP-ETRN)
I rather see this as a benifit than as a shortcomming, but like everything in
here open to discussion.
Hope on some replies