Subject: RE: [Simple] Re: Draft-campbell-simple-im-session-01: Head of Li ne Blocking

From: Adam Roach <[email-masked]>
Date: Wed, 23 Apr 2003 14:48:22 -0500

Paul Kyzivat writes:

> But I'm not sure of the details of using multiple shared connections. 
> Are you suggesting that for a single session, small messages might go 
> over one shared connection, and large messages might go over another 
> shared connection? 

Based on earlier discussions with Ben, I can answer this for him.
Yes.

> If so, there could be very obvious problems with 
> messages arriving out of order. I don't recall what, if anything, is 
> proposed to cope with that.

The relays could trivially enforce ordering. In practice, if a client
sends a message that requires using the "large messages" pipe,
it will usually be tied up sending the large content to the relay
so that  it can't send another message in the same session. If there
is a substantial difference in bandwidth, the relay could simply
quarantine subsequent messages until it was finished sending
the big message.

/a
_______________________________________________
Simple mailing list
[email-masked]
https://www1.ietf.org/mailman/listinfo/simple

---

From: Ben Campbell <[email-masked]>
Date: 23 Apr 2003 15:23:21 -0500

> quarantine subsequent messages until it was finished sending

By quarantine, do you mean refuse new messages until it has gotten rid
of the big one? Or would the relay buffer unsent messages locally? Or
you could even move the session to a "big content" connection for the
rest of its life.

I agree there are several trivial ways to handle this between relays. It
is harder to handle it between endpoints, or between endpoints and
relays, as the binding of connection to session is more explicit here.
If we accept Paul's requirement for multi-user clients, this would seem
to be inadequate; that requirement seems to take us down the road to e2e
chunking.

---

From: Paul Kyzivat <[email-masked]>
Date: Thu, 24 Apr 2003 15:00:07 -0400

> quarantine subsequent messages until it was finished sending

How? The messages headers don't contain anything that can be used to 
order the messages. The only likely candidate is the transaction id, but 
it is only a token.

	Paul