Subject: Re: Multicast over Satellite !!

From: "sukumar sivaram" <[email-masked]>
Date: Wed, 29 Jul 1998 16:01:26 +0100

What a terrible waste of time and money! This can be done by virtually
anyone and big companies like Teleglobe should be doing things far more
important and productive.

suki

-----Original Message-----
From: Steve Goldstein <[email-masked]>
To: Martin Koyabe <[email-masked]>
Cc: [email-masked]' <[email-masked]>;
[email-masked]' <[email-masked]>;
[email-masked]' <[email-masked]>;
[email-masked]'
<[email-masked]>; [email-masked]'
<[email-masked]>
Date: 29 July 1998 15:02
Subject: Re: Multicast over Satellite !!

At 8:21 AM -0400 7/29/98, Martin Koyabe opined:
| Hi,
|
| The major issues in providing this has been asymmetry and high latency,
|unless trade-offs are done. Anyone with further info leads, I could look
|at apart from protocols supported by StarBurst and GlobalCast ?
|
| Martin.

I cannot shed any light on this except to forward a press release that says
that StarBurst and Teleglobe will be using multicast for web warehouse push
via satellite multicast using Intelsat:

INET '98: Teleglobe, Intelsat Team on Satellite System for Internet

Global satellites will push Web content to Internet service providers in
far-off lands, making access cheaper.

by Kristi Essick, IDG News Service July 22, 1998, 3:28 p.m. PT

GENEVA -- Canadian Telecommunications provider Teleglobe has teamed up with
satellite operator Intelsat to jointly beta test a multicasting and
replication system that aims to push selected Internet content to multiple
sites around the world over a satellite network, the companies announced
here Wednesday.

The idea is to push frequently accessed Internet content to servers around
the world so that users don't need to pull data from sites off the Internet
in far-away countries, the companies said. The multicasting software system
was developed by Maryland-based A&T Systems.

During the first phase of the trial, which will begin in November,
Teleglobe will cache preselected popular content, as well as content
requested by the kiosk operators, the company said. Teleglobe will also
strike deals with content providers who wish to offer their material on the
push system. In this phase, the content will be pulled to a "warehouse" on
the Intelsat base station. However, in the future, the warehouse itself
will be able to receive pushed content, including music, sports events, and
real-time news.

Teleglobe plans to offer the service commercially by mid-1999, the company
said. While it won't be solely aimed at Internet service providers in
developing countries, that is where the demand will be greatest for
satellite-based content provision, according to the company. Four ISPs will
be involved in the test: South Africa Telecom, Cyprus Telecom, IDSC Telecom
in Egypt, and Embratel in Brazil.

The satellite-based Internet service replaces a leased-line situation in
which an ISP would need to have a constant connection to the Internet,
Teleglobe said. Since it is very expensive to lease lines in developing
countries, a satellite setup allows ISPs to save money and pass along these
savings to their customers, Teleglobe said. With content cached locally in
the country, users won't have to go out onto the Web and pull information
from servers located across the world, which saves time and reduces network
traffic, the companies said.

Teleglobe offers services to telecom providers and ISPs around the world
via its network of 41 earth stations and undersea cables.

Copyright © 1998 PC World Communications. All Rights Reserved. Use of this
service is subject to the PC

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---

From: "Falk, Aaron" <[email-masked]>
Date: Wed, 29 Jul 1998 11:46:21 -0700

There are some folks at a startup called SkyCache looking at multicast
over satellites to distribute web caches. See www.skycache.com.

--aaron

---

From: john stevenson <[email-masked]>
Date: Wed, 29 Jul 1998 14:40:00 -0400

Martin and Lloyd,

With regard to the LEO satellite concepts, they are not well suited to 
multicast because the satellites rely on the use of many small-coverage spot 
beams, into and out of which any fixed community of multicast receivers will 
be shuttled with great difficulty.  This is primarily a physical layer issue,
 never mind the protocol stack problems.  And, please don't hold your breath 
while waiting for (LEO-based data) services to be available any time soon 
.....

The public Internet multicast system which Steve Goldstein has pointed you 
to look at today was developed, through the conceptual phase, here at 
INTELSAT.  It is tailored to work in pre-existing GEO satellite capacity 
(preferably ours!) and on an international basis via global or hemispheric 
antenna coverages of the earth.  Data multicasting from/to private networks 
via GEO satellite is something we have successfully done at INTELSAT for 
more than two years, using several different "protocols" (including 
StarBurst's MFTP).  Nicely paying customers now exist for GEO-satellite 
delivered data multicast applications.  In no case - private data or public 
Internet - are there latency issues with multicasting in the applications 
layer.  In fact our multicast-to-cache Internet system is designed to 
overlay pre-existing point-to-point links already operational commercially 
via satellite (so that telecom companies and ISPs don't have to buy new 
antennas).  And asymmetry of the links is not an issue either - it 
translates for the end-user into an additional savings in service cost, and 
is in widespread international use for point-to-point Internet via satellite 
links today.

Hope this is helpful.  If you have new advanced degree topics in mind, then 
LEO concepts and their engineering issues will be fine for years to come.  
If you want to run a commercial push service based on an innovative 
combination of satellite multicast (reliable) and advanced (pre-fetching) 
and scaleable caching, with a global market, then stay in touch.

And, yes, there are indeed other somewhat similar developments out there 
......

John Stevenson
-------------
Original Text
>From EEP1LW@SMTPGATE (Lloyd Wood) [email-masked]}, on 29/07/1998 12:18 
PM:
To: KOYABE@SMTPGATE (Martin Koyabe) [email-masked]}
Cc: FED-IP-M@SMTPGATE ("[email-masked]'") 
[email-masked]}, IPMULTIC@SMTPGATE 
("[email-masked]'") [email-masked]}, RM@SMTPGATE 
("[email-masked]'") [email-masked]}, TCPSAT@SMTPGATE 
("[email-masked]'") [email-masked]}

Martin Koyabe writes:

> The major issues in providing this has been asymmetry and high latency,
> unless trade-offs are done. Anyone with further info leads, I could look
> at apart from protocols supported by StarBurst and GlobalCast ?

For upcoming broadband LEO satellite constellations, overlaying of
different protocol stacks appears to be the major problem. (for
example, Motorola's original Celestri proposal included a GEO
component for broadcast, which suggests that the LEO component was
never expected to be multicast-capable; hardly surprising, since each
satellite was envisaged as an ATM switch which IP would be tunnelling
through.) 

See the 'supporting group applications via satellite constellations
with multicast' paper at:

http://www.ee.surrey.ac.uk/Personal/L.Wood/publications/

for more on this.

L.

thinks mbone-over-satellite just isn't the preferable solution.

<http://www.ee.surrey.ac.uk/Personal/L.Wood/>PGP<[email-masked]>

---

From: Ken Miller <[email-masked]>
Date: Mon, 3 Aug 1998 13:53:23 -0400

Congrats, Joe. We also have erasure correction and pro-active FEC based on the work of C. Hanle, who presented at the Cannes RM meeting last September, working in the lab and plan on integrating it with our MFTP engine to be available in our products in future. MFTP has had unicast feedback from the start as the primary feedback mechanism.

We agree that FEC techniques are quite valuable, especially in wireless networks with relatively high error rates or in situations with many thousands of receivers even when the loss rate may be relatively low.

Ken

>>Reply to your message of 7/29/98 9:47 PM
	>>Just finished some initial live demonstrations of the MDPv2 reliable
	>>multicast application over an asymmetric satellite suite!  The
	>>erasure-based parity repairing technique we developed proves very useful
	>>here.  In this demo, we used the unicast feedback option since reciprocal
	>>multicast was not available on the backchannel.
	>>
	>>See http://manimac.itd.nrl.navy.mil/MDP  
	>>binaries downloadable, sdr plugins, and some docs on-line...
	>>
	>>Have fun!
	>>
	>>-joe
	>>
	>>
	>>
	>>
	>>
>>End of message