Subject: RE: support for packet drop priority

From: Yoram Bernet <[email-masked]>
Date: Tue, 20 Jan 1998 08:09:13 -0800

> In IP that could work at the edge router performing metering, but probably
> not at the end user (I would send all my packets with high prio !)
> 
	[Yoram Bernet]  You can still do it at the end user. If the first
hop router is policing, then setting all your packets to high pri will only
hurt you, since the router will drop indiscriminately. If you are allowed to
set the priority or the CLP equivalent, then you will have some control over
which of your traffic gets dropped during congestion. You would be wise to
use it accordingly. 

	There is this recurring conception that "we can't let the host do
the marking, 'cause they'll mark them all at high priority". The cause for
alarm, is that the network downstream will be overrun. We must keep in mind
that the first network that is not in the same admin. domain as the host,
will be policing anyway (to protect their network). Even if we told them
that we won't mark packets - they'd have to police. So - each network has
the responsibility of protecting itself per its agreement with its users.
Each user should have the responsibility of telling the network how it wants
its traffic treated (since it knows best).

---

From: Karl Auerbach <[email-masked]>
Date: Tue, 20 Jan 1998 10:21:10 -0800 (PST)

> alarm, is that the network downstream will be overrun.

(I'm agreeing with you...)

It's probably worth reminding ourselves that we already trust hosts to do
some "self-sacrifice for the good of the whole" kinda things like TCP slow
start and congestion avoidence.

But even if we trust hosts, we still gotta have policing -- else we'll
open up the newspaper (or get spam) selling OS/IP-stack software patches
or widgets that go inline on the net interface cable that bump-up the QoS
settings on outgoing packets.  [Maybe somebody should patent the concept
to prevent the bad guys from doing it. ;-) ]

Since it is the applications in the user's host that will have to both
request and react to QoS settings, there will have to be a means of
communicating that information to whever the true QoS settins are done. 
And that channel will have to be protected or policed against
manipulation. 

		--karl--