Subject: DECIDES BOF 2 Agenda, IETF 46 in DC

From: Jon Crowcroft <[email-masked]>
Date: Fri, 29 Oct 1999 08:32:53 +0100

We have been given a 60 min slot for the DECIDES 2 BOF - while this is
a tad short for the number of folks who want to speak, I think we
should remember that tradition has it that you expect people to read
your i-d's before a BOF (and WGs), so you only need to lead a
discussion - the draft agenda is below - its tight. 

I will do one more pass over the agenda, but once we've done that, it
will be strict.

thanks

jon

- - ----------------------------------------------------

Agenda
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Draft agenda for 2nd DECIDeS BOF, 46th IETF 

BOF Deployment Considerations of Implementing Differentiated Services (DeCIDeS)

60 Minutes.  14.15-15.15, Tuesday November 9, Empire, Omi Shoreham, DC

Problem Re-Statement and News (see the Document) - 
	[email-masked]
	Jon Crowcroft 5 mins

Measurement
	Terena/TF-TANT Report Tiziana Ferrari <[email-masked]>
	(see www.cnaf.infn.it/~ferrari/tfng/ds-test.html) - 10 mins

	Snelnet ADSL diff-serv trial measurements
	"Wentink, M.M." <[email-masked]> - 5 mins

Simulation 
	A.L.Narasimha Reddy TCP results - 10 mins

	Prehofer Christian <[email-masked]>
	Traffic Engineering for IP Networks with Real-Time Traffic - 5 mins
	a simple scheme for admision control together
with simulation results for real-time traffic.  Lars Westberg, Ericsson Research       , 5 mins
	[email-masked], [email-masked]

Operations
	 Martha Zimet, Nokia - diff-serv Network Operations - 5 mins
	 Martha Zimet <[email-masked]>

Theory: from traffic engineering paths and PHBs to SLAs - 5 mins
	Using the Class Selector PHBs (or, finding gold in the sand)
	 Constantinos <[email-masked]>

	[email-masked] - 5 mis
	Does signaling based traffic conditioning scale?"

Where does this work go next in the IETF?
	1/ OAM WG to define protocols/procedures for diff serve deployment 
		e.g. like mboned, define tools for debugging (dtrace,
		dpathchar, etc)
	2/ TA WG to explore inter-domain exchange of diff serve capability
		e.g. look at bandwidth broker and survey family of
		protocols for brokering  - rsvp, snmp, rap/aaa, etc
	J Crowcroft et al - 5 mins

 --------------------------------------------------->
 
BOF Deployment Considerations of Implementing Differentiated Services (DeCIDeS)

Motivation.

The IETF WG on Differentiated Services (diff-serv) has been meeting now for 
over a year now and has made excellent progress. The framework, architecture, 
DS Field definition, and format for traffic conditoners document, and most
importantly , two PHB definitions have been specified.

So what is the problem?

The Integrated Services WG (int-serv) (with its related groups such as 
ISSLL and RSVP and others), has also defined a set of protocols and 
mechanisms for enhanced services in the Internet. The difference between the 
int-serv and diff-serv approaches is that int-serv (at least the Guaranteed 
and Controlled Load services) is amenable to analysis. Effective bandwidth 
calcualations, and the thesis by Parekh shows how the admission tests for leaky
bucket characterised traffic and delay bound for the path can be
calculated. The difficulty with IS has been in designing
implementations that scale (hence a great deal of work in state
aggregation in RSVP, and in fast generalized port specification
classifiers, as well as  the work on efficient queue data structures
and insert/retrieve algorithms, such as WF2Q and approximations such
as SFQ). Indeed, there are network QoS calculi (by Rene Cruz and also
by Jean-Yves le Boudec).

Meanwhile, with diff-serv, the difference is that there can be no
obvious analytic theory of diff-serv. A path can be constructed out of
a sequence of hops each with a PHB and some associated SLA. However,
the service (and provisioning of service) necessarily depend on the
actual network topology and traffic conditions that prevail.

This is a positive aspect of diff-serv, since it gives providers (and
router vendors) a lot of design freedom in how they deploy actual
services (and associated tarrif structures).

However, to evaluate a diff-serv PHB is now a complex task, and
requires simulation or measurement. To date, only modest simulations
and measurements have been carried out.

[Aside: of course the exact same argument
applies to figuring out call blocking
probabilities in int-serv type networks]

Objectives.

To prepare a document that outlines evaluation framework for PHBs by
suggesting realistic topologies and traffic patterns for measurement
or simulation work. Note that there is a health warning associated
with simualtion - see reference [2] below.

Reading

0/ http://www.cs.ucl.ac.uk/research/decides/
Notes and most slides from previous BOF

1/ http://www.cs.columbia.edu/~hgs/internet/traffic.html

2/ Paxson, V., and Floyd, S., Why We Don't Know How To Simulate The
Internet, Proceedings of the 1997 Winter Simulation Conference,
December 1997. at
http://www.aciri.org/floyd/papers/wsc97.ps