Subject: [NSIS] Comment on draft-fodor-intserv-wireless-issues-00.txt

From: [email-masked]
Date: Tue, 27 Nov 2001 15:07:50 +0200

Gabor, Fredrik & Brian,

Some comments on your draft:

http://www.ietf.org/internet-drafts/draft-fodor-intserv-wireless-issues-00.t
xt

My first, high-level comment is that I am somewhat confused about
the applicability of this work for NSIS.  It seems that you are
looking specifically at Resource Reservation (Intserv) and layer
2 (cellular).  Those issues are out of scope.  If the intention
was to provide some insight into the NSIS problem area based
upon this particular area, some text stating such would be 
useful.

In section 2 - General Background, you state:

   The Appendix develops a model for the radio access network ...

Is this model the basis for some implementation or simulation
work?  If so, including the results of such studies would
be useful, otherwise it seems that you a proposing an
architecture, which IMO, would be out of scope for NSIS.

Small nit: try not to split diagrams across page breaks
(see figure 1 & 2).

Additionally, while I am familiar with 3G architecture, I 
don't know if everyone is.  It might be much more useful
to show a more functional-type architecture.  For example,
RNCs do quite a bit, and even though they are shown as 
a network element in the 3GPP architecture, they may, in
fact be shown as quite seperate functions within an
architecture.

I have a small bit of trouble with this statement:

   In wireless networks, the physical resources (e.g. frequency
   spectrum, transmission power or time slots) are typically scarce.
   The transmission is therefore optimized in order to utilize the
   resources as efficiently as possible.

Wireless can be considered as a layer 1 / layer 2 issue.  Is
it more scarce than copper on a dial up connection?  Somehow,
I would say it is good design practice to make protocols
that are conservative in what they send ...

Finally, in section 6 - Security Considerations, you have listed:

   None

Are you sure about that?  There will have to be considerations
about if the user is authorized to gain the resources desired,
by allowing levels of QoS, there is the possibility of DoS-style
attacks by monopolizing resource, etc.

best regards,
John

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---

From: Brian Williams <[email-masked]>
Date: 28 Nov 2001 08:25:44 +1100

Hi John.
> upon this particular area, some text stating such would be 
As mentioned earlier, the draft was not written for NSIS, and hasn't
been updated for it. Thus, it is not completely applicable in it's
current form. However, it has some aspects which we consider relevant
for NSIS as described below. 

Problem area
Some layer 2 technologies (predominantly wireless) offer layer 2 bearers
with widely varying characteristics. Optimal QoS performance
(considering both QoS characteristics and cost) depends on the ability
to determine the most appropriate layer 2 bearer for the traffic.

Requirements
There is a requirement to provide sufficient detail about the traffic
flow specification and required QoS performance characteristics to
enable the selection of the optimal QoS bearer for technlogies that
provide multiple bearer options with different QoS characteristics. 

As new layer 2 technologies develop and older technologies may trail
off, the range of information that is needed for the available
technologies will vary. Thus, there is a need for a core set of
information aimed to cover the needs of a majority of layer 2
technologies. In addition, there must be an extensible mechanism to
provide other detailed information needed by specific layer 2
technologies.

I am aiming with my presentation to pick out the salient points for
NSIS. I hope to send you a preliminary copy of the presentation for
comment.
Regards, /brian