[Sois-tcons] RE: Updated version of TCONS Red book on CWE

[Scott,Keith L.]

Jane,

I have a question about figure 2-2 (TCONS/OBL Architecture).  There are
both Intra-Network and Inter-network layers shown, as well as a number
of different data link layers.  In Athens I thought the consensus was
that TCONS would provide time-critical services over a single
subnetwork.  Is this still the intent of the architecture, with TCONS
using TCP/UDP/IP to provide time-critical service, or is the intent to
attempt to provide time-critcal services over (between) heterogeneous
data links?

What about the paragraph in section 3.1: "The network layer is
responsible for routing datagrams across heterogeneous sub-networks,
from source address to destination address, delivering them to the
required destination."

If the thought is that TCONS networks will support networking protocols
(e.g. NP/IP), and that these networking protocols can be used to get
'out' of a TCONS (providing time-critical services) subnetwork and into
other subnets, I think that fits well with the SIS view of things.  The
red "Inter Network Service Interface" in Figure 2-2 then is then (or
maybe could be) a standard sockets interface, with time-critical
requirements managed by the TCONS API?  Reading it this way, an
application requiring time-critical services would use the TCONS API;
the TCONS API block would choose a transport service (TCP/UDP) and
interact with the QoS function to allocate slots, etc.  I don't think I
have any problems with this interpretation.

Using this interpretation, if TCONS is making use of TCP/UDP/IP, one
_could_ redraw figure 2-2 with the TCONS API as part of TCONS, the red
line from the TCONS API to the Intra-Network Service Interface as part
of TCONS, and the transport and network protocols as (IETF/adopted by
SIS) standards.  TCONS would also 'own' the Intra Network Service
Interface (which it must control in order to preserve/protect its
time-critical service), as well as the Intra-Network stuff.

Does this match the current TCONS thinking?

		--keith


>-----Original Message-----
>From: Jane K. Marquart [mailto:Jane.K.Marquart at nasa.gov] 
>Sent: Monday, August 29, 2005 10:50 AM
>To: sois-tcons at mailman.ccsds.org; Scott,Keith L.; 
>Peter.Shames at jpl.nasa.gov; dstanton at keltik.co.uk
>Subject: Updated version of TCONS Red book on CWE
>
>All,
>
>I've incorporated MOST comments into Version 2 of the TCONS 
>Architecture 
>Redbook and put on the CWE (also attached for convenience).  
>Please provide 
>feedback promptly.  There continues to be confusion as to what 
>and why of 
>the architecture.  Hopefully, the updates will help to 
>clarify.  Feedback 
>from SIS is especially requested so we don't have disconnects 
>and wind up 
>dealing with the same issues in Atlanta as we did in Athens.
>Thanks to all who have responded thus far.  I'll continue to try and 
>resolve any outstanding comments.
>