[CMC] Re: [CESG] Draft-3 CCSDS report to IOAG-11

Tue Jun 12 11:45:16 EDT 2007

Adrian, there are some very positive things here and in line with our
thinking.

For the bit stream HDLC I have restate that running IP in this way as a
cross-supported service should be not mandated by CCSDS. AOS defined this
service as delivering a stream of bits, not as delivering a packet, other
services are used for packet delivery. As implemented on ISS the AOS  bit
stream service turned out to be one of the biggest headaches we had, but
fortunately, even there,  it was never used as a x-supported service and only
for private internal Agency data. I firmly believe this is where it belongs
and if Agencies want to use it privately then this is fine by me.

Where I can agree is on the need to develop an evolutionary path for the use
of IP. I think one of the main issues with the previous work by SIS was that
it was too visionary and targeted at systems too far in the future. It was
therefore very difficult for other Agencies to contribute as our missions are
much less ambitious and do not have the requirements to which SIS was
offering solutions.  As you may recall, this was the reason that we initiated
the work on the near term Mars mission. Essentially, we knew that we could
not change too much but still needed to improve matters and provided a way
forward. We therefore limited the scope of the work to the existing
infrastructure + the known missions in the next 15 years.

We will very soon, next week or so, deliver draft outputs from the Mars work
(corrected Green and a magenta book on the X-support services, including  a
PICs proformae).  If the CCSDS could use this approach as a model to build
on, then I think we have a solid way forwards to which we could sign up to.

Regards,

//ct

             "Adrian J. Hooke"                                               
             <adrian.j.hooke at jp                                              
             l.nasa.gov>                                                  To 
                                        Chris.Taylor at esa.int                 
             12/06/2007 16:12                                             cc 
                                        greg.kazz at jpl.nasa.gov,              
                                        kscott at mitre.org, CCSDS Management   
                                        Council <cmc at mailman.ccsds.org>,     
                                        CCSDS Engineering Steering Group -   
                                        ADs <cesg at mailman.ccsds.org>         
                                                                     Subject 
                                        Re: [CESG] Draft-3 CCSDS report to   
                                        IOAG-11                              

At 12:25 AM 6/12/2007, Chris.Taylor at esa.int wrote:
      Adrian, I see that the option to multiplex IP using HDLC as a private
      bit stream is still in the list. I thought we had killed this one with
      the response to the recent review where quite a few Agencies were
      strongly against it. It therefore seems incorrect to give it any sort
      of credibility as a x-support option to be considered by the IOAG.

Chris: reports of its death are greatly exaggerated. Use of Virtual Channel
Access (VCA) and Bitstream service is perfectly legal in the AOS
specification, and for whatever reason the Constellation program has elected
to use that legal option in the standard. Whether or not it's a good *idea*
to use those options it is another matter: but that's an operational decision
about what standard features of AOS will be cross supported and what won't -
and that decision should be made by the IOAG agencies.

       I think this should first be resolved within CCSDS before exposing it
      outside and would recommend it's removal.

The only way to remove it from the AOS standard is to modify the CCSDS Blue
Book. That means forming a BOF, re-starting a WG and processing Pink Sheets.
And in the process you might be removing capabilities that actually have
utility, if properly and honestly applied.

Alternatively, we could - in conjunction with the IOAG - form a joint
CCSDS-IOAG Working Group to come up with a Recommended Practice (Magenta
Book) that specifically states the recommended architecture,  protocol suite
and evolutionary strategy for moving towards a future era of Space
Internetworking. In fact, we have the nucleus of that in the current CCSDS
Cislunar Space Internetworking WG, which is stalled on this same issue.
Cislunar, as currently constituted, is very poorly supported by any Agency
other than NASA - although it does enjoy strong support from the very people
who made the Constellation decision, as well as from your local U.K.
representative from Cisco/Surrey Space Technology (who seems to have his own
agenda that's different from the European agencies).

My recommendation is to remove the work 'Cislunar' from its title and to
re-charter it as the 'CCSDS Space Internetworking Working Group'. Instead of
focusing on just the Earth-Moon communications environment, it would in fact
expand to cover the whole domain of space internetworking and it would "work
backwards from Mars" to come up with a Recommended Practice that covers the
whole problem space. It would be properly staffed by nominated personnel
representing the senior CCSDS Agencies and would contain appointed
representatives from the IOAG network operators.  "Visitors" to the working
group would be treated as such: their inputs would be listened to and
respected, but they would not be voting members.

I'd like to get the reaction of the CESG and the CMC to this proposal.
Obviously, there is going to be extensive discussion about the "IP-in-Space"
topic at next week's IOAG meeting. We then have a CMC meeting in Brussels the
following week to "catch" the results. If CCSDS would like to propose this
new Working Group strategy, then I have it on good authority that NASA will
be willing to supply the necessary resources to lead it. We could then get
moving on the work over the Summer, leading up to the Fall CCSDS meeting.

Best regards
Adrian

Adrian J. Hooke
Chairman, CCSDS Engineering Steering Group (CESG)