Annex 9 to AVC-743R

Update of H.32X Network Adaptation Protocol Reference Model

The update of the H.32X Network Adaptation Protocol Reference Model following discussions at the Kamifukuoka meeting, is shown attached.

Some issues with respect to this new diagram are as follows;

•	explicit mention of the PES part of H.222.0 has been removed, mainly due to lack of space.  The PES layer can be re inserted if there is strong feeling that it should be shown.

•	the H.24X (TD19 Kamifukuoka) and T.120 (AVC-640) protocol stacks are illustrated.  It is not the intent of the diagram to specify either the H.24X, or the T.120 series, protocol stack, but to show the point of connection with H.222.1, if H.222.1 is to be used to transport these protocols.

•	H.261 is mentioned in the video coding part, but H.221 is not mentioned in the multiplex part.  Perhaps H.221 should be shown as an alternative multiplex.

•	review of the list of H.222.1 and AAL functions is required.  The list of functions are now listed in the notes on the following page.  

•	it is intended that this diagram will become Appendix II of Recommendation H.222.1.  Its purpose is informative.

	...

Figure 1.   H.32X network adaptation protocol reference model.

Notes to Figure 1.

1)	Video frame asynchronous signals are not shown explicitly in this Figure.  Whether or not there are included in H.24X, a similar protocol stack will be applicable.

2)	The H.24X and the T.120 protocol stacks may use H.222.1.  The Figure shows the anticipated points of connection.

3)	H.222.1/H.222.0 functions:
	-	multiplexing
	-	timebase recovery
	-	media synchronization
	-	jitter removal
	-	buffer management
	-	security and access control
	-	inband signalling
		    - unacknowledged
		    - acknowledged
	-	trick modes

4)	This point represents the point at which the ISO/IEC 13818-9: Real Time Interface applies, if it is applicable.  This point may not always be physically realised.

5)	H.222.1 network adaptation functions:
	-	jitter removal
	-	bit error correction

6)	Although AAL type 1 currently addresses constant bit rate operation, it is anticipated that the AAL type 1 SAR sublayer, and perhaps some of the AAL type 1 CS toolkit, will be used for variable bit rate operation.  In the case of variable bit rate operation not all of the following AAL type 1 CS sublayer functions are applicable.

	AAL type 1 CS functions:
	-	transmission clock recovery
	-	jitter removal
	-	bit error correction
	-	cell loss correction
	-	data structure preservation

7)	AAL type 5 (CPCS) functions:
	-	bit error detection
	-	cell loss detection
	-	data structure preservation

8)	There are no proposals for a new AAL type 2.

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