[Sls-slp] Post CLE meeting version of USLP White Book 3

Kazz, Greg J (312B) greg.j.kazz at jpl.nasa.gov
Tue Apr 19 16:21:24 UTC 2016

Dear SLP WG member,

Please find the updated clean version of the lastest USLP White book (dated April 19) on the CWE along with the updated issues list. See the names of the two files below.


1) The USLP file is USLP Space Data Link Protocol April 19 2016

2) The issues file: USLP Issues 2016 4 19

There are several open issues  that I have identified in comments in this version. They are:

1. Section 2.1.1 Architecture
The use of the term transfer frame for the PDU at ISO level 2. USLP defines the PDU at ISO level 2 to be the transfer frame. This is a very important and necessary statement in this document.

2. Section VC OCF Service

This section states: "For a given service instance, only one user, identified with the GVCID of the Virtual Channel, can use this service on a Virtual Channel.  Service data units from different users are not multiplexed together within one Virtual Channel.[K(1]

 [K(1]Last paragraph is incorrect.  It should say: For a given service instance, only one user, identified with the GMCID, can use this service on a Master Channel.  However GMCID does not yet exist in CCSDS. Need consensus from WG on how to proceed here.”

3. Section 2.2.4 Restrictions on Services

These restrictions do not appear to be valid under USLP. Clearly where USLP signals the service, coexistence of services can occur. For future discussion with the WG.

4. Section 3.6.1 Overview of VC_OCF Service

Related to #3 above. The problem is that the managed parameter for allowing a VC to contain a OCF is a VC managed parameter, but the OCF service receives and delivers all the OCF_SDUs from any VC with the MC that it receives. This problem needs resolution within the WG.

5. Section 5.3 Managed Parameters for a MC and in 5.4 for VC

VCID 63 for OID frames.  should value 63 be reserved  for all OID frames within USLP in all cases ?

6. Section 5.4 Managed Parameters for a VC

CLCW Reporting Rate - this parameter is defined in TC SDLP. Actually I think it is never mentioned elsewhere in TC SDLP. However it is important for setting the COP-1 timers. We should discuss it and see whether we want to impact also TC + COP-1.

I plan on calling an additional telecon to discuss these issues before May. I will be sending out a doodle poll today. Please respond with your availability. Thank you !

Best regards,

Greg Kazz
Chairman SLP WG
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