FW: The return of the report

Tue Sep 17 06:34:04 CDT 2002

Here's the feedback. I'll be working on this in the background, but
input is encouraged.  Clearly there is a disconnect and we have to get
our story straight so we can answer these questions. The nuts and bolts
of the issues have to support our claims, or we're wasting our and
Tony's time.

--Ivan

-----Original Message-----
From: Michael Daw [mailto:mike.daw at man.ac.uk] 
Sent: Tuesday, September 17, 2002 3:24 AM
To: Sue Rogers; Stewart Macneill; Stephen Booth; Richard Ansorge; Paul
Jeffreys; Mike Giles; Mark Hayes; Mark Cavanagh; Malcolm Atkinson; Liz
Carver; Kate Caldwell; John Gordon; John Brooke; Jeremy Sharp; Ivan R.
Judson; Henry Hughes; David Salmon; David Hutchison; David De Roure;
David Boyd; Chris Osland; Brian Gilmore; Alan J. Flavell; Peter Clarke
Cc: galvez at hep.caltech.edu
Subject: The return of the report

Dear team,

It's not over yet!

Below is Tony's second e-mail on the subject of the report forwarding a
response from the VRVS team at Caltech. (Just so you know, his first
e-mail said "I liked your report very much and hope we can take
something forward from your recommendations".) 

So - Tony wants the report revised in light of these comments. While
we're at it, we should also incorporate some concerns expressed by a
couple of other people. Then the report can be disseminated widely, as
Tony says.

What I suggest is that those of you who are interested in helping with
the re-draft let me know. I'll then co-ordinate some kind of meeting to
discuss how to take this forward. I'd like to keep the current
contributors on this distribution list so that they can comment on
revisions and remain on the contributor list. I've cc-ed Phillippe too
so that he - or someone at Caltech - can be a full member of the
re-draft team.

Please tell me if you can think of better ways forward, or have
questions or comments on anything related (or unrelated, for that
matter).

--Mike

 -----Original Message-----
From: Tony Hey [mailto:Tony.Hey at epsrc.ac.uk]
Sent: 16 September 2002 13:44
To: 'mike.daw at man.ac.uk'
Cc: Tony Hey; Ray Browne (Ray.Browne at dti.gsi.gov.uk); James Fleming;
Anne Trefethen
Subject: FW: FW: Background Document for JCSR

Mike 

Thanks for your note - I am forwarding some comments from the VRVS team
at Caltech which seem to me to have some merit! And this answers my
strategy as to publication - I would like your team to consider these
comments and produce any revisions (if necessary - but I will require an
answer from you to their points!) to your paper. Then we would like it
circulated widely. There is also every possibility that JCSR will be
willing to fund some of your recommendations ...

Best wishes 

Tony 

Professor Tony Hey 
Director e-Science Core Programme 
Engineering and Physical Sciences Research Council (EPSRC) 
Polaris House 
North Star Avenue 
SWINDON 
Wiltshire  SN2 1ET 
ENGLAND 
Tel: +44(0)1793 444022  Fax: +44(0)1793 444505 
http://www.epsrc.ac.uk  
http://www.research-councils.ac.uk/  
http://www.escience-grid.org.uk  
http://umbriel.dcs.gla.ac.uk/NeSC/general/    

-----Original Message----- 
From: Philippe Galvez [mailto:galvez at hep.caltech.edu] 
Sent: 15 September 2002 21:48 
To: Harvey Newman 
Cc: Tony Hey; Philippe Galvez; Alan J. Flavell 
Subject: Re: FW: Background Document for JCSR 

Dear Tony, 

Harvey and I went over the document and made additional comments. I hope

you will find it useful and constructive. feel to contact us for more 
detail. I will be glad to discuss any topics that you will find 
appropriated. 

        Regards, 
        Philipps 

cc: Harvey Newman, Alan Flavell 

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

    o My first comment concerns the list of contributors. I see on the 
list Ivan Judson (from ANL/AG, AG's architect) and Jim Miller from 
InSORS. In this regard, I am a bit surprised that the people preparing 
the report didn't  contact us directly if they wanted a balanced 
evaluation, while avoiding technical errors and misconceptions. 
Hopefully, Alan Flavell  contributed to the VRVS parts as he is one 
person who understands for the most part what VRVS is. 

    o The executive Summary is good. 

    Comments by Section follow: 

    o 2.1: Technically speaking, I don't understand the planned usage of

openMCU to enable interoperability between H.323 and AG. First of all, 
VRVS has done it -- completely. Second, it is definitely not the right 
technical solution. I already informed the AG guys about it but looks 
like they want to insist on using it without first understanding the 
openMCU architecture and its limitations.. 

    o 2.4: The interoperability between AG and VRVS is already done. The

further deployment of AG/VRVS in UK and other countries could be done 
easily, as well as full support for more AG virtual venues. 
Something that people didn't get is that  the current AG/VRVS Gateway 
has never been in the "Funded Tasks development list". We simply did it:

because there was a need,  and because our architecture was flexible 
enough so that we were able to do it with minimal resources. This is 
just one of several examples where people do not quite realize the 
potential of our realtime software infrastructure, and conversely assume

limitations in the VRVS system that don't exist. 
In this case if people think that VRVS/AG gateway improvements are 
needed right now, then we could do it in return for a moderate amount of

funding -- to improve the gateway GUI, to deploy it, and to provide a 
bit of support. The funding is only needed because we would have to push

other tasks on our long in-progress development list; or (better) we 
would take on another engineer to keep all of our milestones (including 
the VRVS/AG ones) on schedule. 

   o 2.4: I don't understand "It is not possible for an Access Grid to 
participate in a VRVS session". This is not true. And the solutions 
proposed do not take in account the current technique used in the 
gateway. 
It would be better to ask us is there is a presumed  problem: (a) to 
find out if it is already done, (b) to allow us to propose solutions, 
which in the great majority of cases will be quite straightforward for 
us. 

    o 3.4, H.323/H.320:  These are Not broadcast quality as  mentioned 
here. CIF (352 X 288) is half the resolution of broadcasts. In 
continuous presence (4 videos on a screen) one has QCIF  for each video 
which is 4 times less resolution per video than  broadcast. 

    o 3.7 AG: A solution purely multicast based is surely not "the only 
fully scalable solution for large-scale collaboration" as it is 
mentioned in the report. It has been demonstrated since the  early 
1990's that the opposite is true. In contrast, it has been  recognized 
(e.g. at high performance network meetings organized by DOE this Summer)

that using unicast tunnels where needed to interconnect mulitcast 
domains  is demonstrably scalable. This is why VRVS has  spread to 60+ 
countries, and precisely why VRVS  is architected the way it is. 
 The claim that pure multicast is scalable in this section is  in 
contradiction with the following sentence, that mentions  that it will 
take few years for having all UK academic LANs  with multicast 
capability. We must point out that multicast at network level, with 
large TTL is now considered dead by leading experts such as Linda 
Winkler and Matt Matthis. VRVS's unicast tunnels inter-connecting 
multicast domains  has been recognized as the "obvious" globally 
scalable  solution; in contrast to what is said in this report. 

    o 3.7 H323: Here it is not mentioned that H.323 devices are very 
sensitive to packet loss. The adaptive/predictive protocols used  by 
H.323, while bringing higher interactivity and quality per unit 
bandwidth, also are more sensitive to persistent "artifacts" on the 
screen. Especially if packet loss is above a few tenths of one  percent.

    o 3.9 AG:  An ACL list do not provide a secure way to operate. 
Multicast is definitely not the best technique for providing security 
since almost anyone on the network can sniff the packets. In this 
particular case, the only solution is encryption from the applications 
and today this could be done via the Mbone  tools (Vic/Rat). This is not

particular to the AG, but only related to the Mbone tools. In addition, 
the encryption   provided in the Mbone tools is very basic, and anyone 
enough competence will be able to decrypt it. 

    o 3.13: I don't understand what is meant by "The AG configuration 
applied at the e-Sciences Centers makes them unsuitable for VRVS 
conferences". Are the AG nodes there different from all the other AG 
nodes elsewhere; if so, in which ways ? 

    o 5.2: I am surprised by the cost for the AG. Platinum 30,000 LS 
(UK), One could equip a whole site with desktop cameras !. 

    o 8.1:  Again, we see an incorrect comparison of  VRVS (a realtime 
software infrastructure integrated with many clients) with the 
application tools themselves: Netmeeting, QT, CUSeeMe,...etc..  Once 
again this is a failure to understand that VRVS is not a client 
application, but rather provide the infrastructure upon which  many 
client applications can run, and interoperate. It is like  comparing 
Cisco routers and the Cisco IOS software, with FTP  or Telnet. 

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

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