----- Original Message -----
Sent: Tuesday, January 30, 2001 8:13
PM
Subject: RE: RPR perf: Regarding the
vote
Khaled,
I aggree with Offer. As we made our way, over a year, in
becoming a working
group in IEEE to define a MAC
we have picked up a lot of information
on various
approaches for a RPR based system. What stood out as wide
difference are system level issues like fairness and congestion
control
contrasted with how similar each of the
MAC header definition was.
The reality was that
each RPR system dealt with different services at the
box level.
What happened during the study
group phase was a testimony of
existence of a
common shared ring, multi-node, spatial reuse paradigm
by describing "system" level features of each type of box that
could sit
on an RPR ring. Now we are in the role
of defining a MAC. We need take the
value of this
education but move forward and go define the basic
element - the MAC.
Although, it is inconceivable of an RPR box without
features to
address congestion on the ring it is
not within the usual realm of MAC
definitions.
MAC's decide WHEN to put ANY packet GIVEN to it by the
system on its client interface on the INDICATED media interface
and not
necessarily decide WHICH packet. MAC's
can indicate to the client indicate when
it is
ready for the next packet giving the client the flexibility in
either
deffering transmission or giving the MAC a
certain type of packet.
A MAC's role in a
networking system is to predictably deliver a packet given
on its client interface to the physical layer. Both the
assurance of
the packet being delivered
accurately over the physical layer and keeping a tab
on which MAC is putting more or less traffic is usually not a MAC
layer issue.
Some networking MACs made this their
business and died a vey young death on
their way
to adoption (ATM's ABR). Hence I view fairness on rings a system
level issue and not a MAC issue. Further, we need an
official position in the working
group of this
kind of jurisdictional issue as Offer pointed out.
I agree, that one must define a MAC by understanding
common types of congestion and
fairness schemes
that exist. However, the actual definition of a particular
congestion or fairness scheme is to narrow, rigid and
will fail to provide
flexibility and
differentiation in products that adopt RPR as a technology.
It has been very intriguing to me that while you are
taking a straw (amended
words) poll on the type
of traffic (TCP or raw) I wonder if you will find
any different answers than the rest of this world has already
found in terms
of what types of congestion
mechanisms work for these types of end-to-end
flows when they travel across a series switches. Even if you do
find a different
flow control mechanism or
congestion algorithm this would not give RPR an edge
over ethernet switches in a ring since at the MAC layer you will
only be able
to control aggregate flows (a
combination of TCP and raw). It would be instructional
for us to review how ethernet decided to deal with this with the
option of
using pause frames (sort of an XON/XOFF
scheme) in Ethernet. What algorithm triggers a
PAUSE frame is certainly not part of the Ethernet standard.
The point I am making
is we must be able to focus
ourselves to the MAC and not get side tracked by
system level issues.
let us try to work what is relevant to MAC and not spend
time on developing a new
fairness alogirthm or a
congestion mechanisms - we will never get the standard
done in time to rally support in the industry that RPR is a
promising technology as seen
by steady progress
toward standardization by gaining confidence through the
widespread commonality
Raj Sharma
-----Original Message-----
From:
Khaled Amer [mailto:khaledamer@xxxxxxx]
Sent: Tuesday, January 30, 2001 7:01 PM
To: pazy@xxxxxxxxxxxxxxxxxx
Cc:
'Reflector RPRSG'
Subject: Re: RPR perf:
Regarding the vote
Offer,
Thanks for the input.
You're
right. That's why I carefully worded it as a straw poll vote.
You're also right about cautioning about the need to
carefully define what
needs to be done and what
is meant by terms like fairness, ...etc.
Since we need so much more time to handle these issues,
we formed a separate
adhoc for that activity with
all the experts invited to participate and help
out with this effort. Only getting an hour or two as part of the
mainstream
discussion won't cut it. Also, seeing
that we have so much more to do, we
had to
postpone starting the simulation efforts till next meeting. In the
meantime, we hope to continue to hold productive,
fruitful discussions on
the reflector so that we
can make significant progress in March. Also, as I
indicated in January, I'm requesting that we get about 8 hours in
March to
plow through all these issues after
working on them as much as possible on
the
reflector. Hopefully this will help us make good progress in March,
and
also proceed properly to ensure that we're on
the right track.
Your input is very welcome, and any other input is
appreciated. This helps
make sure that we're on
the right track.
Thanks again for the
input.
Khaled Amer
Chairman, RPR
Performance Modeling adhoc Committee
President,
AmerNet Inc.
Architecture Analysis and
Performance Modeling Specialists
Address: 13711 Solitaire Way, Irvine, CA
92620
Phone:
(949)552-1114
Fax: (949)552-1116
e-mail:
khaledamer@xxxxxxx
Web:
www.performancemodeling.com
----- Original Message -----
From: Offer Pazy <pazy@xxxxxxxxxxxxxxxxxx>
To: 'Khaled Amer' <khaledamer@xxxxxxx>; 'Donghui Xie'
<dxie@xxxxxxxxx>
Cc: 'Reflector RPRSG'
<stds-802-rprsg@xxxxxxxx>
Sent: Tuesday,
January 30, 2001 6:19 PM
Subject: RE: RPR perf:
Regarding the vote
> Hi all,
>
> I hate to be the "procedure" cup, but I have to
remind everybody that we
are
> not in a position to take any "formal votes" yet. Also, we
should not
treat
>
previous SG decisions as binding and worry about "reopening"
decisions.
The
>
first time we can officially vote is in March. This is not just a
> theoretical issue or one which concerns the perf.
ad-hoc only. I suspect
> that the performance
work will take a significant amount of the time and
> resources of the entire WG and therefore the decision of what
to do and
how
> much
needs to be taken carefully.
>
> I realize that a lot of preparatory work is needed
in order to bootstrap
the
> simulation work and the earlier we do it the better. On the
other hand, we
> cannot let the simulation
work shape the outcome of what the MAC will look
> like. I read a lot of references to fairness, congestion
control, and
other
>
features which 1) are far from being properly (and consensus-ly)
defined,
> and 2) have not been formally voted
as being part of the requirements.
>
> I plead for caution and patience. Trying to rush
things will only hurt us
> later on in the
process when consensus will be hard to achieve.
>
>
>
Offer Pazy
> Sr. Product Manager
> Native Networks
> 15
Gonen St.
> Petah Tikva 49170
> Israel
> Tel: +972 3 921-0010
Ext. 229
> Fax: +972 3 921-0080
> pazy@xxxxxxxxxxxxxxxxxx <mailto:pazy@xxxxxxxxxxxxxxxxxx>
> http://www.nativenetworks.com
>
> The Native Way = Ethernet
Simplicity + SONET Reliability
>
>
> -----Original
Message-----
> From:
owner-stds-802-rprsg@xxxxxxxx
[mailto:owner-stds-802-rprsg@xxxxxxxx]On
> Behalf Of Khaled Amer
>
Sent: Tuesday, January 30, 2001 22:24
> To:
Donghui Xie
> Cc: Reflector RPRSG
> Subject: Re: RPR perf: Regarding the vote
>
>
>
> All,
>
> Please put:
> RPR perf: vote
> in the e-mail subject field.
>
> and select one of the
options:
> - TCP
>
- raw packets
> - Abstain
>
> This will help me a lot.
> You can add comments following that if you
want.
>
>
Thanks.
>
> Khaled
Amer
> President, AmerNet Inc.
> Architecture Analysis and Performance Modeling
Specialists
> Address:
13711 Solitaire Way, Irvine, CA 92620
>
Phone:
(949)552-1114
Fax: (949)552-1116
>
e-mail:
khaledamer@xxxxxxx
>
Web:
www.performancemodeling.com
>
>
>
>
----- Original Message -----
> From: Donghui
Xie <dxie@xxxxxxxxx>
> To: Khaled Amer
<khaledamer@xxxxxxx>
> Cc: Reflector
RPRSG <stds-802-rprsg@xxxxxxxx>
> Sent:
Tuesday, January 30, 2001 11:02 AM
> Subject:
Re: RPR perf: My thoughts
>
>
> >
> > Hi All,
> >
> > TCP traffic performance over RPR is definitely
the most important part
of
> > RPR MAC evaluation. However, I don't think TCP traffic
performance over
> RPR
> > should be the first step. What we need here is to
establish a clean and
> > simplistic RPR
MAC performance baseline in a timely manner. TCP network
> > behavior can be pathological due to many reasons ranging
from
application,
>
> RTT estimation factors to TCP simulation models. By just specifying
a
> Tahoe
> >
or any other flavor of TCP would not bring consensus to TCP traffic
> > generation specification any time
sooner.
> >
>
> Using raw UDP traffic will never produce a definitive
performance
> > conclusion for RRP MAC, but
it does allow us to focus on RPR MAC
> >
performance baseline. RPR MAC performance evaluation should be a
> > progressive advancing process, from simple to
complex and from partial
to
> > complete. Any shortcut may well be counter
productive and time
consuming.
> >
> > I support raw UDP
traffic as step #1 simulation.
> >
> > Best Regards,
>
> Donghui Xie
> >
> >
> > At 10:22 AM 1/30/01
-0800, Khaled Amer wrote:
> >
> > >All,
> >
>
> > >I'd like to suggest that we
avoid involving ourselves in heavy duty
>
traffic
> > >characterization problems
(whether traffic is self-similar or not, and
>
all
> > >of that). As we know, this is
an active area of research, and we can
spin
> > >our wheels trying to
resolve this. There are so many schools of thought
> on
> > >this. I don't
believe that it will have a dramatic effect on what we're
> > >trying to accomplish here.
> > >
> > >Now, on
another related point, in August, we had arrived to the
> conclusion
> > >that we'll
start step#1 of the simulations using raw traffic with no
> > >protocols involved, and make the runs with TCP and
UDP (and mixes) as
> step
> > >#2. We voted on this and agreed among ourselves to
do so. I looked at
my
> > >records and found that the Luminous guys didn't
attend that meeting
when
> we
> > >made that decision.
Apparently they had to leave.
> >
>
> > >I'm seeing that there are a
lot of discussions on the reflector going
>
back
> > >to this point. Even though I
don't want to take a step back on
decisions
> > >that were already
made and voted on, so that we continue to make
> progress, I
> > >guess we
need to reopen this one and make a decision again.
> > >
> > >I'll open it
up for an electronic straw poll vote.
> >
>
> > >Here is what we'll be voting
on:
> > >
>
> >As the first step in running the simulations, we should use
traffic
> streams
> > >that:
> > >1) use
TCP streams as step #1 in the simulations, and not just raw
data.
> Raw
> > >data and other protocols (like UDP) will follow
immediately afterwards
as
> > >step #2.
> > >2)
use raw packets with no protocols as step #1 in the simulations.
TCP
> and
> > >UDP protocols (as well as mixes) will follow
immediately afterwards as
> step
> > >#2.
> >
>
> > >Please vote by selecting one
of the following choices:
> > >
> > >- TCP
> >
>- raw packets
> > >- Abstain
> > >
> >
>Please remember that this vote is just for the first set of
simulations.
> > >Just
trying to narrow down the number of runs to a manageable subset
for
> the
> > >first batch of simulations. We all agree that we're
going to be doing
all
> of
> > >the other steps in
the presentation that I gave as step #2.
>
> >
> > >Please cast your vote by
Friday (2/1). I'll post the results that
evening
> or
> > >over the weekend.
> >
>
> > >Please put:
> > > RPR perf: vote
> > >in the e-mail subject field.
> > >
> > >In
either case, we're going to decide on some simple traffic input
> process
> > >that
we can use as a starting point too. We can get into more elaborate
> ones
> > >later,
if we see that it would be appropriate and productive for this
> group
> > >to use
(and if it doesn't get us all into a black hole!)
> > >
> > >Waiting for
your vote.
> > >Best regards.
> > >
> >
>Khaled Amer
> > >Chairman, RPR
Performance Modeling adhoc Committee
> >
>President, AmerNet Inc.
> >
>Architecture Analysis and Performance Modeling Specialists
> > >Address: 13711
Solitaire Way, Irvine, CA 92620
> >
>Phone:
(949)552-1114
Fax: (949)552-1116
>
> >e-mail:
khaledamer@xxxxxxx
> >
>Web:
www.performancemodeling.com
> >
>