[Sis-csi] IPv6?

[Lloyd Wood]

At Friday 08/06/2007 17:45 +0200, Chris.Taylor at esa.int wrote:
>Just to stir things up a bit, has it really been decided that we will use IP
>on our future links. From the discussion it seems like a done deal but our
>ESA studies and opinion is that IP doesn't bring us much other than a bit
>more address space that we probably don't need anyway. Rather than  discuss
>the merits of IPv4 and 6 it may be more productive to critically examine the
>application of IP to see how it may be employed or not. I should say that I
>have no particular issue with the use of IP its just that I think the problem
>is much wider and by concentrating on v4/v6 there is a danger of missing the
>real problems - IP doesn't work on links that have disjoint connectivity

Actually, IP works just fine on links with disjoint connectivity, as large amounts of delay/disruption tolerant networking work and mobile ad-hoc work by many people have shown. For example, we've developed our own IP/UDP-based transport protocol for moving files over disjoint links, and there are other protocols that work over IP in these environments. TCP won't work well, but then TCP's operational range is surprisingly limited. TCP is not IP.

See:
http://www.ee.surrey.ac.uk/Personal/L.Wood/dtn/
ftp://ftp-eng.cisco.com/lwood/dtn/README.html (IE users: passive ftp must be ON in Tools/Options... Advanced tab)
- Saratoga: a Delay-Tolerant Networking convergence layer with efficient link utilization, Lloyd Wood, Wesley M. Eddy, Will Ivancic, Jim McKim and Chris Jackson, submitted to the Third International Workshop on Satellite and Space Communications (IWSSC '07), September 2007.
- Saratoga: A Convergence Layer for Delay Tolerant Networking, Lloyd Wood, Wesley M. Eddy, Will Ivancic, Jim McKim and Chris Jackson, work in progress as an internet draft, version -00 submitted to the IETF, May 2007.

For a detailed discussion of how IP can be used in the disjoint environment of intermittent space links, see:
http://www.ee.surrey.ac.uk/Personal/L.Wood/cleo/
ftp://ftp-eng.cisco.com/lwood/cleo/README.html (IE users: passive ftp must be ON in Tools/Options... Advanced tab)
- Using Internet nodes and routers onboard satellites, Lloyd Wood, Will Ivancic, Dave Hodgson, Eric Miller, Brett Conner, Scott Lynch, Chris Jackson, Alex da Silva Curiel, Dave Cooke, Dan Shell, Jon Walke and Dave Stewart, special issue on Space Networks, International Journal of Satellite Communications and Networking, vol. 25 issue 2, pp. 195-216, March/April 2007 - particularly section 14.

The primary argument for using IP imo is that you can just reuse well-developed commercial technologies without reinventing the wheel, minimising your overall software development and testing costs.

(How much is esa spending on developing Spacewire? IP already runs well over LVDS HDLC serial links, and is used on them in space.)

regards,

L.


<http://www.ee.surrey.ac.uk/Personal/L.Wood/><L.Wood at surrey.ac.uk>