[CESG] Action CMC-A-2012-04-07

Stuart Fowell Stuart.Fowell at scisys.co.uk
Fri Jan 25 03:32:49 EST 2013


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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  |RE: [CESG] Action CMC-A-2012-04-07
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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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