Subject: Re: support for packet drop priority

From: Zheng Wang <[email-masked]>
Date: Wed, 21 Jan 1998 14:50:27 -0500

> ...what Steve's worried about is prevented by proper billing,
> policing, ingress shaping, or penalty actions

Unless you can identify which customer the traffic belongs to, there is
no
easy way of preventing that. If you can isolate traffic for different
customers,
you dont have to worry about the waste - you can not punish people for
wasting
their own resource/money. 

Let's face it, a single bit can only divide the traffic into two groups:
upper class and lower class. The upper class takes the cream of the
cake,
and for the lower class, it's good old best effort. If one has a way of
regulating the lower class traffic, why not just apply to current
Internet?

Once a customer is sure that its upper class traffic will get through,
there
are strong incentive to send its lower class traffic more aggresively
just
in case tehre are spare bandwidth available. 

Also, how to make sure that the cake is big enough for all upper class
traffic
is not a trivial problem. The example of upper class in airline is often
used 
to support priority in the Internet. But I think it is not a good
example.
The reservation for upper class seats is done for each flight and for
each
customer. In the airline business, they dont classify customers at the
check-in
and then let them go as they wish. Imagine what will happen if a
customer,
once checked in as upper class, can choose where he/she wants to go and
preempt economy class customers anywhere. 

Cheers
Zheng

-- 
Zheng Wang                  
Bell Labs Lucent Technologies
http://www.bell-labs.com/user/zhwang

---

From: Steve Deering <[email-masked]>
Date: Wed, 21 Jan 1998 14:34:57 -0800

At 11:50 AM -0800 1/21/98, Zheng Wang wrote:
> no easy way of preventing that.

The idea (and technical challenge) of the penalty box is indeed to identify
misbehaving sources at whatever granularity necessary (transport flow,
source host, source organization, whatever) and give them reduced (less
than "fair") service.

>                                  If you can isolate traffic for different
> customers, you dont have to worry about the waste - you can not punish
> people for wasting their own resource/money.

Unless you are talking about a world in which all communication is across
per-customer-pair dedicated links (or TDM slots, CBR channels, or the like),
the resources of concern that a customer may waste are *shared* resources
that could otherwise be put to productive use by other customers; they are
not the private resources of a single customer.

Steve

---

From: Zheng Wang <[email-masked]>
Date: Wed, 21 Jan 1998 18:46:47 -0500

> source host, source organization, whatever) and give them reduced (less

Sure. The interesting question is what is the definition of 
"misbehaving" and what is "fair"? It seems to me that they should be 
linked to the contract/how much resource is paid for. So,
we are not here to "punish" people but to enforce the agreed 
contracts.

> not the private resources of a single customer.

Again, I dont disagree. But as you have pointed out that it would be 
difficult to send the per-path info to the edges to limit the traffic,
we should at least make sure that the traffic at the congested point 
is properly regulated so that the users who do not adapt will only 
hurt theirselves. Of couse, resources are wasted before the congested 
point. But, by removing the incentives for mishaving, hopefully
the majority of the people will adapt for their own benefit.

Cheers
Zheng