Subject: Multicast over Satellite !!

From: Martin Koyabe <[email-masked]>
Date: Wed, 29 Jul 1998 13:21:49 +0100

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.

---

From: Steve Goldstein <[email-masked]>
Date: Wed, 29 Jul 1998 09:44:15 -0400

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

---

From: Joe Touch <[email-masked]>
Date: Wed, 29 Jul 1998 07:04:15 -0700

>via satellite multicast using Intelsat:

We have a project at ISI supporting web push using multicast, adapted
from Apache, that runs on FreeBSD. It currently uses AFDP for reliable
multicast
transport (which does not optimize for satellite), but that's a plug-
replaceable component). It might be a useful place to play with some of these
issues (there's an API, in particular, that's accessible from command line
and remotely).

More info, including a demo, is at:

	http://www.isi.edu/lsam

Joe

---

From: Lloyd Wood <[email-masked]>
Date: Wed, 29 Jul 1998 17:18:07 +0100 (BST)

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: Mitch Robinson <[email-masked]>
Date: Wed, 29 Jul 1998 13:15:08 +0800

Hello:

Multicast over satellite should not be a big deal for anyone, its being done in
several networks very effectively today.  If however, you really want to use the
internet over satellite, then you are looking at deploying TCP Spoofing.  We have
a TCP Spoofing implementation that selectively controls the acknowledgments that
must traverse the space link.  Obviously, controlling the acknowledgments
tremendously increases the availability of bandwidth in these Asymmetric Data
Flow (ADF) networks, where typically we see a Fat Bit Pipe (the FBP) blasting
away at a Xmbps, while the in-band return, trickles back at 38.4kbps.

If you set it up correctly, you should be able to multicast to your hearts
content, while surfing the net
in the hundreds of kilobits/second, while watching a real time video, i.e.
distance learning, while you are still chugging away on all the legacy stuff in
the network.

Mitch

Joe Touch wrote:

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From: Joe Macker <[email-masked]>
Date: Wed, 29 Jul 1998 21:39:43 -0700

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