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RE: Chang'E 3

2013-12-27 17:57:47
AB

The people who have spent decades working in CCSDS, who developed and 
standardised the SCPS stack based on TCP/IP, who developed and standardised 
CFDP (which runs over TCP/IP), and who are currently standardising the bundle 
protocol as the latest effort to get space to adopt networking, would, of 
course, strongly disagree with your statement that there are still no standards 
for space.

http://en.wikipedia.org/wiki/CCSDS
http://public.ccsds.org/publications/archive/714x0b2.pdf
http://public.ccsds.org/publications/archive/727x0b2s.pdf
http://public.ccsds.org/sites/cwe/rids/Lists/CCSDS%207342R2/Attachments/734x2r2.pdf
But what do they know?

The ETSI group who standardised satellite communication and carriage of IP 
traffic with DVB-S2 (and extensions) and DVB-RCS , would, of course, strongly 
disagree with your statement that there are still no standards for space. 
http://www.etsi.org/technologies-clusters/technologies/satellite/
But what do they know?

Again, I'm backing my statements with references, so that they are not merely 
unsupported assertions.  (And why is UDP inefficient?)

Lloyd Wood
http://about.me/lloydwood
________________________________________
From: Abdussalam Baryun [abdussalambaryun(_at_)gmail(_dot_)com]
Sent: 27 December 2013 22:31
To: Wood L  Dr (Electronic Eng)
Cc: mcr+ietf(_at_)sandelman(_dot_)ca; ietf(_at_)ietf(_dot_)org
Subject: Re: Chang'E 3

I was discussing/commenting on the subject as the thread did about using space 
internet protocols on satellites, still no standards for space.

AB

On Friday, December 27, 2013, wrote:
AB

The Moon is arguably a satellite of Earth, but the distances are different from 
LEO and GEO. That affects TCP performance.

TCP was designed with geostationary satellite hops in mind - see eg RFC829. I 
use TCP across geostationary satellites daily.

I back up my statements with experience and references. What do you back yours 
with? Why is UDP inefficient?

Lloyd Wood
http://about.me/lloydwood
________________________________________
From: Abdussalam Baryun [abdussalambaryun(_at_)gmail(_dot_)com<javascript:;>]
Sent: 27 December 2013 06:01
To: Wood L  Dr (Electronic Eng)
Cc: mcr+ietf(_at_)sandelman(_dot_)ca<javascript:;>; 
ietf(_at_)ietf(_dot_)org<javascript:;>
Subject: Re: Chang'E 3

So if TCP has problems then MPTCP has problems then they may not be preferred 
for that satellite networking. For LEO SATNETs also there are problems for 
using TCP. The UDP is a good solution in general but not efficient, but always 
I think the SATNETs may need some special internet transport protocols because 
they are having more dynamics in the net's lower layers.

AB


AFAIK vanilla ftp/TCP has (only?) been used on CHIPsat from LEO, but that did 
not have much data to transfer.

We designed http://saratoga.sf.net with the idea of a continuous UDP stream of 
data from Pluto in mind...

Lloyd Wood
http://sat-net.com/L.Wood/


________________________________________
From: ietf [ietf-bounces(_at_)ietf(_dot_)org<javascript:;><javascript:;>] On 
Behalf Of Abdussalam Baryun 
[abdussalambaryun(_at_)gmail(_dot_)com<javascript:;><javascript:;>]
Sent: 26 December 2013 16:40
To: Michael Richardson
Cc: ietf(_at_)ietf(_dot_)org<javascript:;><javascript:;>
Subject: Chang'E 3

Transport protocol for satellites depend on the applications, the network 
dynamics, links and transmission channels. IMO the use of MPTCP for Back2Earth 
may not be the best option making the communication complex, not sure why did 
you hope to use it with this project.

AB




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