[Sois-tcons] Telecon this Friday

Abhijit Sengupta Abhijit.Sengupta at jpl.nasa.gov
Wed Jun 1 20:12:56 EDT 2005

At 6/1/2005 09:55 AM, Jane K. Marquart wrote:
>Dear TCONS/OBL members,
>We'd like to have a telecon this Friday at 11:30 EST to discuss plans for 
>getting out the books.  I've included the following from Steve to get us 
>thinking about it before the telecon.
> >The key issues are how we define the QoS and where we split the stack for
> >the red books. There are currently two views on this, both of which I agree
> >with (something about training as a physicist and getting to grips with
> >particle/wave duality):

Please recall how the QoS specification comes from TCOAS - basically, 
defining bounds on different service parameters like delivery time or 
jitter, bandwidth etc. Your definition of QoS needs to be something that 
can readily be mapped from specification from TCOAS.

> >1. Split TCONS/OBL at the bottom of TCP/IP and above the sub-network level
> >where the QoS is done. This is the view that Rick put forward. In this case
> >OBL offers a set of services which provide different QoS to TCP/IP and
> >(and possible TCONS protocols).
> >2. Split TCONS/OBL below the sub-network level so that the QoS services are
> >generic to all the underlying buses. This is the view that Dai put forward.
> >It preserves the role of TCONS looking at the QoS issues (in line with the
> >charters) but is disadvantageous if all the QoS if handled differently by
> >the various buses.

In either case then, transport or network layer functionalities do not care 
about QoS specification which might be a serious problem. Please recall 
that QoS specification from TCOAS is not concerned with whether the source 
and destination applications are on same subnetwork or not - in fact the 
applications do not have a clue (in general) where the recipient 
application is running.


All personal and professional opinions in this email are my own
and do not represent, in any way, the opinion or policy of JPL

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