Subject: Naming those hunks of data

From: David Newman <[email-masked]>
Date: Mon, 28 Sep 1998 15:28:56 -0400

At the Chicago bmwg meeting there was consensus on the need for a
generic, transaction-based forwarding rate measurement in benchmarking
firewalls. However, the group did not agree on a specific term for this
measurement. Jeff Dunn proposed PDU (protocol data unit), which is the
closest we've come to hitting the mark.

With all due respect to Jeff (who's made invaluable contributions to
this effort), I'm leery of using the term PDU. It's nothing against the
concept; what PDU describes is exactly what's needed here. My concern is
that I've heard the term PDU used quite a bit in discussing ATM, but
rarely in IP circles (well, maybe by Scott Brim or Berry Kercheval, but
they work with both ATM and IP). Since I'd like this document to be
technology-neutral, I'd prefer to use as generic--and as
all-encompassing--a term as possible.

I propose that we use the term put forth by Kevin Dubray --
"transaction." A transaction can be many things: It might be an IP
packet, the payload of an ATM cell, an e-mail message, a DNS query and
response, or an entire FTP session. 

Given the amount of wriggle room the term offers, there is obviously a
strong need for the tester to describe exactly what comprises each
transaction. For example, it wouldn't do to compare forwarding rate
where one offered load consisted of an FTP sessions transferring a
1-Gbyte file and another consisted only of a stream of 21-byte IP
packets. Thus, it would be helpful to describe several sample
transactions when we get to the methodology document. 

What I like about the term transaction is that it's technology-neutral,
and it allows me to describe many kinds of loads I'd want to throw at a
firewall. My concern is that the term may be *too* broad to be useful
(though given sufficiently rigorous described of offered load it may be
ok).

Before adding a definition in the draft, I'd be curious to hear what you
think.

dn

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From: "Bob Mandeville" <[email-masked]>
Date: Thu, 1 Oct 1998 05:42:48 +0200

I'd like to suggest 'session time' which avoids twisting  layer 2 lingo like
forwarding rate and offered load to have a meaning in the context of layer
3/4/5 measurements. Session time must be explicitly related to the content
of the session.
Bob Mandeville