Subject: RE: [NSIS] Preemption

From: "Gary Kenward"<[email-masked]>
Date: Fri, 5 Apr 2002 12:05:56 -0500

The issue is not whether network xyz supports pre-emption or priorities, or
EF, or AF, or CBR or ABR, 
or PDP contexts. The issue is whether the NSIS protocol definition is going
to explicitly address every
one of the access network specific local QoS solutions through the explicty
definition of protocol fields 
and values, and protocol semantics.

This is not only my view, it is the very first requirement in the wg draft:
 
"5.1.1 Applicability for different QoS technologies.
 
   The QoS signaling protocol must work with various QoS technologies.
   The information exchanged over the signaling protocol must be in
   such detail and quantity that it is useful for various QoS
   technologies."

We can debate the virtues and vices of priority models forever (it's
certainly not a new debate). 
But the actual issue for NSIS is how to support all reasonable QoS solutions
in an efficient manner.
It is my view that defining NSIS protocol fields for every variation is not
the way to proceed.

Regards,
Gary

-----Original Message-----
From: James M. Polk [mailto:[email-masked]]
Sent: April 5, 2002 11:44
To: [email-masked]
Subject: [NSIS] Preemption

Preemption is real and will continue to be real in the real world for
decades and/or longer.

Preemption, other than by randomizing mechanisms, is a deterministic action
based on local policy *only* when there are in place certain differentiators
between packets/flows to appropriately perform this action.

Preemption shouldn't be mandatory in all product implementations. However,
the ability to perform this action shouldn't be omitted from this WG's
output.

The ability to preempt should be optional, and if chosen, should have
specific definitions to follow coming from NSIS.

For examples of preemption in today's networks, merely look at eMLPP in GSM
networks which has 15 levels of Priority with 5 of these levels having
hierarchical preemption characteristics operational. Look at MLPP in US DOD
and NATO networks (5 levels). Verizon and VoiceStream petitioned the US FCC
(Nov 01) to each "enable" eMLPP Preemption in their public deployments of
Wireless throughout the US (if not North America). Many countries have
preemption within their existing PSTN today, many others forbid it (to
clarify - the US is *NOT* one of them).

If NSIS wants to migrate any of these networks over to IP, or be part of any
migration or transition, preemption ought to be defined the WG, albeit as an
option - with specifics surrounding that/those options.

*************************************
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James M. Polk
Consulting Engineer
Office of the CTO

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