[Sls-slp] [Sls-sea-dls] Order of Processing between TC-SDLP, COP-1 and SDLS

[Kazz, Greg J (313B)]

Ed,
Yes, why should the COP continue once the entire system knows there has been an error. Also easy to implement.

Sent from my iPhone

On Apr 11, 2013, at 7:22 PM, "Greenberg, Edward (313B)" <edward.greenberg at jpl.nasa.gov> wrote:

> Thanks for your input.  I am still concerned with your item 2 as copied:
> - -- - - - - - - - - - - - - - - - - -
> On 4/11/13 1:57 AM, "Marjorie de Lande Long" <marjorie at delandelong.com>
> wrote:
> 
>> 2) For a system where the SDLS processing is before FOP-1 at the sending
>> end and after FARM-1 at the receiving end
>> 
>> 2.1  In this system, a frame can be lost because of an SDLS failure
>> after the frame has been acknowledged and delivered by FARM-1. This is
>> similar to an error being detected when reassembling a packet from
>> multiple frames.
>> 2.2  It is happening above COP-1, so, strictly speaking, the COP-1
>> delivery assumptions are not compromised.
>> - The COP-1 delivery guarantee applies only as far as the output from
>> the FARM: if a frame suffers an error after that, then that is not
>> COP-1's problem. (It is a problem and it needs to be reported but it is
>> not COP-1's problem.)
>> - An example of one of these errors is mentioned in 2.1: there are
>> existing systems that handle this error.
>> 
>> 2.3  The SDLS failure is detected above the FARM, as the frame is being
>> passed upwards.  So it does not look so convenient to try to pass
>> information downwards (e.g. into the FARM) so that the SDLS Error Flag
>> can be set in the CLCW.
>> 
>> 2.4  The failure needs to be reported - see 3.5 and 3.6 below.
> - - -  -- - - - - - - - - - - -  -
> 
> First of all the implementation of the flag is simple.  A wire from the
> SDLS process that is set to a 1 when a frame is rejected and reset to a 0
> when a frame is accepted is all that is needed.  This wire is sampled and
> becomes the flag when the CLCW is composed.
> 
> Defining and then using a new CLCW to carry the information about the
> details of an SDLS failure seems simplistic and according to the frame
> processing rules would be in clear.  Identifying why an SDLS failure
> incurred when no errors where caught needs more than a 32 bit diagnosis.
> I would suspect that a packet of information would be more appropriate.
> Even if encryption was not used for the frame the packet's content could
> be encrypted. 
> 
> The rationale for the flag in the CLCW was to let the COP know that an
> error occurred and its continued presents would inform the COP that
> continuation of COP activities was useless.  
>