[CESG] Action CMC-A-2012-04-07
Scott, Keith L.
kscott at mitre.org
Fri Jan 25 08:26:01 EST 2013
Good point. I think that from how the areas have been divided, 'real-time' (deterministic delay) onboard communications that span link-layer technologies would fall into the SIS domain, while of course anything that's specific to the link-layer (e.g. TTEthernet) is not in SIS. We don't currently have a good solution for internetworked real-time communications within SIS (and as you know, such a service is difficult to realize in the Internet as well -- though the restricted scale of onboard networks might make it easier). If there's a mission need for 'internetworked' (multi-hop over heterogeneous data link layer) communication then maybe you or Chris could bring it up to the CESG/CMC and we (CCSDS) could spin up another attempt at a WG in some area or as a cross-area effort.
--keith
-----Original Message-----
From: Stuart Fowell [mailto:Stuart.Fowell at scisys.co.uk]
Sent: Friday, January 25, 2013 3:33 AM
To: Scott, Keith L.
Cc: Nestor.Peccia at esa.int; cesg-bounces at mailman.ccsds.org; cesg at mailman.ccsds.org; Chris.Taylor at esa.int
Subject: RE: [CESG] Action CMC-A-2012-04-07
Keith,
>From the SOIS perspective, I have a couple of comments on the text that
together relate to the issue of real-time communications, especially
application-to-application communication onboard a spacecraft:
1. The last sentence of the third paragraph makes no mention of
timeliness of communication.
2. Bullet a) should also recognise that communication within a
spacecraft can have tightly bounded timeliness requirements that cannot
be met by TCP alone (and maybe not appropriate at all). So perhaps the
comment about round trip times being low (~<2s) should be qualified. Or
perhaps the SIS strategic goals are not targeting onboard communication?
If so this should be made clear.
Happy to discuss further :)
Stuart
-----Original Message-----
From: cesg-bounces at mailman.ccsds.org
[mailto:cesg-bounces at mailman.ccsds.org] On Behalf Of
Chris.Taylor at esa.int
Sent: 25 January 2013 08:19
To: Scott, Keith L.
Cc: Nestor.Peccia at esa.int; cesg-bounces at mailman.ccsds.org;
cesg at mailman.ccsds.org
Subject: RE: [CESG] Action CMC-A-2012-04-07
Keith, I have some problems with point C on CFDP. We will be using CFDP
on
many of our future missions, we therefore need a stable and active CFDP
standard covering class 1 and class 2 on point on point links, possibly
with
SFO for relay. I have no problem evolving CFDP to have a subset to
operate
with DTN (class 1 +) but we need to maintain the existing CFDP class 1/2
capabilities.
Regards,
//ct
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Proposed updated SIS text:
The objective of the Space Internetworking Services (SIS) Area is to
address
all of the routine communications services and protocols supporting
end-to-end communications among applications, particularly where these
communications may span multiple heterogeneous technologies. Areas
addressed
by SIS include the networking infrastructure to support
application-to-application communication onboard a single spacecraft,
communications among multiple spacecraft, and communications between
space-based applications and their counterparts on Earth and/or other
planetary bodies.
The SIS Area deals with communication services and protocols that are
independent of specific link technology (as a lower layer bound) and
independent of application-specific semantics (as an upper bound). Thus
the
SIS area covers essentially the network through application layers of
the OSI
reference model.
SIS protocols use the underlying communication and infrastructure
services
provided by the Space Link Services (SLS) and Spacecraft Onboard
Interface
Services (SOIS) areas and any other onboard networks, and provide the
networked connectivity needed by applications developed in other CCSDS
areas
such as Mission Operations and Information Management (MOIMS) and
Spacecraft
Onboard iInterface Services (SOIS). The SIS services provide
hardware-independent mechanisms for identifying end systems, and provide
communications services that allow users to disregard whether the
communication is over a single data link layer or over multiple hops.
The
capabilities developed by the SIS Area accommodate all ranges of delay,
interactivity, and directionality, although not all protocols are
appropriate
for all environments.
The services provided by SIS protocols free applications from having to
have
intimate knowledge of the underlying communications protocols and
mechanisms,
and from having to know the physical location(s) of the entities with
which
they are communicating. This enables applications to focus on the
application-specific protocols and interactions necessary to achieve
their
goals without having to be involved in the details of communications.
The strategic goals of the SIS Area are:
a) To actively promote the use of Internet standards for data
transport, routing, and auxiliary functions in environments where
end-to-end paths exist and are relatively stable. This includes
the
use of TCP (including options defined by CCSDS and/or IETF) when
round
trip times are low (~<2s), and possible use of UDP for
unidirectional
paths and/or high delays.
b) By 2018: to enable routine communications between Earth and
4-6
lunar and/or near-Earth missions using SIS recommendations for
application, transport, and network services (including the
standard
Internet suite).
c) By 2020: to evolve CFDP to be a purely application-layer
protocol able to run over a range of transfer, specifically
including
the Bundle Protocol and Licklider Transmission Protocol.
d) By 2020: to enable routine Solar System Internet (SSI)
operations
among at least 20 entities communicating over interplanetary
distances
by means of Delay-Tolerant Networking protocols.
===END===
From: cesg-bounces at mailman.ccsds.org [
mailto:cesg-bounces at mailman.ccsds.org] On Behalf Of
Nestor.Peccia at esa.int
Sent: Wednesday, January 23, 2013 9:02 AM
To: cesg at mailman.ccsds.org
Subject: [CESG] Action CMC-A-2012-04-07
R E M I N D E R
Dear all,
We need your collaboration
During the CMC discussion of " the big picture" the issue of our
open
action CMC-A-2012-04-07 came back.
In order to avoid more work that the one specified in the action
(see
below)
==============================================================
CMC instructs the CESG Chairs and Area Directors to review the
current
strategic plan and update as necessary to include strategic
planning
for each area, an overview of CCSDS activities, how the Area/WG
activities are "wired" (interdependent) and how they support other
activities. There should be an emphasis on the capabilities that
result
from the activities of the areas, in order to support decisions
about
starting new work or continuing existing work.
Action: CESG
Due Date: Spring 2013 Meeting (status update at Fall 2012 CMC
meeting,
with examples)
Status: Open
==============================================================
it was proposed to change the action due date from Spring 2013 to
end
February 2013.
In order to tackle the action, I would propose a two phase
approach
* ADs / DADs update the half page Area strategy
(including
interdependent activities and capabilities) (see example
below
for MOIMS text to be updated) 24th January 2013
* NestorI consolidates all the inputs
27th January 2013
* CESG Chair propose updates to all other sections
15th February 2013
* CESG agrees on document to be sent to CMC for
comments.
28th February 2013
==============================================================
Example for MOIMS
2. MISSION OPERATIONS AND INFORMATION MANAGEMENT SERVICES
AREA
The objective of the Mission Operations and Information Management
Services (MOIMS) Area is to address all of the flight execution
phase
applications that are required to operate the spacecraft and its
ground
system in response to mission objectives, and their associated
detailed
information management standards and processes. The focus of this
Area
is primarily on the "mission operations" functions that occur on a
timescale driven by the flight path of the space vehicle. In many
cases
a dedicated community conducts these mission operations, while
"mission
utilization" occurs on a timescale that is convenient for users
and is
often conducted by a separate community. The MOIMS Area ensures
that
application standards exist which facilitate the smooth transition
of
space mission information between the "mission operations" systems
and
the "mission utilization" systems
The strategic goals of the MOIMS Area are:
* By 2006: to develop and deploy the standards that
specify an extensible framework for packaging data and
metadata.
* By 2006: to develop and deploy the standards for
the
exchange of Navigation information (e.g. position, velocity
and
attitude) by establishing content and format for tracking,
attitude, trajectory and ancillary data (e.g., gravity
models,
spacecraft orientation).
* By 2008: to develop and deploy the standards for
the
submission and ingest of digital data sources and digital
metadata to the Archive, for the identification of digital
data
within the Archive and for the search and retrieval of
digital
data and metadata.
* By 2008: to deploy and develop a suite of standard
spacecraft Monitor and Control (M&C) services that are
exposed
for cross support interfaces between M&C and other mission
components
================================================================
[attachment "CCSDS-StratPlan-A01x1y1x1-d5v3-Sep06.doc" deleted by
Nestor Peccia/esoc/ESA]
ciao
nestor
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