[Sois-tcons] White paper contribution.
Massimiliano.Ciccone at esa.int
Massimiliano.Ciccone at esa.int
Mon Jun 13 12:40:17 EDT 2005
Well done Jane !!
I managed to create a folder but I cannot rename or delete it...I will check
with Brian how to do it, please let me know how to name it.
Do you all have access to the private area of TCONS discussion board ?
If not please contact
Oliver Braian at: "Oliver Brian (BTAS)"<brian.oliver at btas.com>
and he will provide you a username and password to access the service.
Like all new things the adaptation is a bit painful at the beginning but I am
sure it will pay off overtime.
Thanks
Max
|---------+------------------------------------>
| | "Jane K. Marquart" |
| | <Jane.K.Marquart at nasa.gov|
| | > |
| | Sent by: |
| | sois-tcons-bounces at mailma|
| | n.ccsds.org |
| | |
| | |
| | 13/06/2005 17.03 |
| | |
|---------+------------------------------------>
>---------------------------------------------------------------------------------------------------------------|
| |
| To: Richard Schnurr <Rick.Schnurr at nasa.gov>, "Scott,Keith L." <KSCOTT at mitre.org>, |
| sois-tcons at mailman.ccsds.org |
| cc: |
| Subject: RE: [Sois-tcons] White paper contribution. |
>---------------------------------------------------------------------------------------------------------------|
All,
I uploaded the 2 documents to
http://public.ccsds.org/sites/cwe/sois-tcons/Documents.aspx
I couldn't create a new folder. Kept getting errors. I also put this e-mail
on the discussion board so as not to lose it. Let's try to keep all
correspondence there from now on.
Thanks!
At 05:38 PM 6/10/2005 -0400, Richard Schnurr wrote:
Hi Keith,
In some ways I am the scribe but I will try to answer anyway.
IP/NP is the current networking layer of choice for SOIS. In some ways
IP/NP could be given to SIS since all the QOS stuff other than the QOS
tagging is below. This would simplify SOIS's life since we would simply
hand this function over to SIS.
The IP/NP layer does perform the routing between OBL.
The span of an OBL is defined by the user. IE if multiple networks of
the same type are available the bridging of those networks would be
implementation specific. This is necessary from a fault tollerance
perspective.
Remember some of the Bus/Lan are networks onto themselves (for example)
JWST is using a SpaceWire network to move data without IP.
The TCONS-API is better than sockets from my perspective since it
captures the close interaction between network messages and software
actions in its call back interface however Jane is the one to discuss
this and Scott's white paper on the messaging service must be
interpreted and implemented.
On the other hand the SOIS API is non-normative since hardware devices
would not implement.
Yes, TCONS currently makes no claims to support QOS over multiple OBL's
(heterogenious or not - IE two separately scheduled SpaceWire networks
would not support end to end QOS). Although doing so would not be hard
if both OBL's were in the same schedule domain.
Steve, put the copyright notice on the document during the shutdown
period. He will have to comment on why.
As far as I am concerned the document is copyright of the CCSDS since
all of this is a group derived work. Otherwise it would be ITAR :).
The US government has the same write to copyright as anyone else. The
current court rulings indicate that US copyright occurs when pen is
placed to paper with or without registration. I am less familiar with
the laws of Greece. Lets not get into this legal stuff.
If my clarifications lead to needed changes let me know.
Cheers,
Rick
At 04:22 PM 6/10/2005, Scott,Keith L. wrote:
So if I understand correctly, the architectural elements say
that:
TCONS (in conjunction with/via OBL) provides QoS over
individual subnets, and that for traffic that spans
heterogeneous subnets, IP is the networking layer?
[Architectural Elements (2,3)] Application interfaces to
'TCONS' are via sockets and/or a TCONS-specific API. TCONS
makes no claims to support QoS over paths containing
multiple OBLs
The inclusion of TCP/IP in the green SOIS box on slide 1 is sort
of odd (since IP/TCP would normally be a SIS thing). But taking
as given that TCONS is a world unto itself in order to provide
time-critical services, and needs a network layer to span
heterogeneous subnets, it sort of makes sense.
BTW: I believe that works by the U.S. Gov't are not eligible for
copyright protection, and I'm not sure what legal standing 'The
TCONS Working Group' has wrt copyright. I'd be sort of
interested if you know more about this.
--keith
From: sois-tcons-bounces at mailman.ccsds.org [
mailto:sois-tcons-bounces at mailman.ccsds.org] On Behalf Of
Richard Schnurr
Sent: Friday, June 10, 2005 11:38 AM
To: sois-tcons at mailman.ccsds.org
Subject: [Sois-tcons] White paper contribution.
Hi all,
OK, based on the last call I drafted the beginnings of a
white paper.
I kept it short - hopefully you can all read the whole
thing.
If we all agree to this structure and the descriptions I
think we can restart the books.
BTW, it would not hurt my feelings if we deleted the OBL
service interface and simply defined a Intra-network
service interface (This is what I did in this white paper).
Not clear that the OBL interface is usable since on board a
spacecraft we are time critical and OBL is a on demand type
of service not coordinated with anything else.
Also, the OBL service interface seems to get in the way
more than it helps. For example some OBL's support
protocol multiplexing. For those that do the Intra-Net
should map directly. We already have IP addresses. It
would seem that mapping directly from IP addresses to OBL
addresses is what is usually done and makes sense.
For these reasons I am proposing that the OBL service
interface be deleted and replaced with a private interface
to the Intra-networking service.
Please read my section on address mapping. It makes sense
to me I think it can be implemented and it is in line with
existing IP implementations.
Steve, I modified the picture to remove the OBL service
interface and to move address resolution inside and between
the Intra-networking service and OBL. (In case you cannot
open the figure again).
If we stick to what is written here I think I can actually
see a way to implement this consistently across various
bus. This is the first time I have had such clarity and I
am going on vacation before any of you spoil it.
I am on vacation next week. So this and the modified
diagrams are my contribution to the white paper.
Rick
PS I did not use the message board because I do not have my
password. Someone can post this if they like. If you
reply to this message Please: do not reply inline - add
your response to the top. After one pass of the in line
comments I cannot follow and on a mailing list like this
the likely hood that I will get many reply's is almost
surely one.
As always correct my thinking as required.
Richard G Schnurr Jr
Chief Architect
Electrical Systems Center
Applied Engineering and Technology Directorate
NASA GSFC Code 560.0
Greenbelt MD 20771
(301)-286-1852
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