[Sls-slp] Frame Validation in 235.1 - need to include AOS frames

[KAZZ, GREG J. (MSFC-HP27)[MOSSI2]]

Dear SLP WG member,

Frame validation is addressed in 235.1 (session control), however it doesn't address AOS frames, which are allowed if U-frames are used.

I modified this section in 235.1 as follows:

5.7.2 Frame Validation
Frame Validation Criteria shall be as follows:
a)      If the first two bits of the Transfer Frame header are:
1)      '00', then the transfer frame is rejected as invalid;
2)      '01', then a valid Version-2 (AOS) Transfer Frame has been received from the TM C&S sublayer (see reference [10]);
3)      '10', then a valid Version-3 (Proximity-1) Transfer Frame has been received from the Proximity-1 C&S sublayer (see reference [4], subsection 3.6.4);
4)      '11', then a valid Version-4 (Unified Space Data Link Protocol [USLP]) Transfer Frame has been received from the Proximity-1 C&S sublayer (see reference [4], subsection 3.6.4).

The current issue of 211.0-B (Prox-1 SDLP) states that AOS frames are to be rejected. The red-1 version of 235.1 simply ignores the '01' option, which doesn't supply guidance to the user.
Please let me know your thoughts?

I also included in Section 2 a discussion of both what a space comm session is as well as Nicola's diagram below that describes the protocol stacks to be used under 235.1. See attached powerpoint file.

Best regards,
Greg



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