Transport classes

Hi again,

as I stated earlier, my wishes about a new mail system
would be to replace plain SMTP mail, Mailing Lists, 
POP3, uucp (rmail/bsmtp), and NNTP in one step.


I therefore propose to classify the transport mechanism

- between two relays as

     - push (like SMTP, NNTP newsfeed)
     - pull (like POP, NNTP fetching)
     - push/pull (both of them)
     - synchronize (push/pull without delete, see below)

  and to further distinguish between 

     - deleting the message after successful transfer (e.g. SMTP)
     - keeping the message (e.g. NNTP)


As an overall traffic classification I'd propose the usual 
three

- unicast (like SMTP)
- broadcast (somehow like NNTP)
- multicast (need to go into further detail, should cover
            both mailing lists and newsgroups, but 
	    support different mechanisms of subscription
	    like central subscription like in mailing lists
	    and decentral subscription like in newsgroups, 
	    furthermore decentral distribution or 
	    central distribution, with or without moderation)


regards
Hadmut