0x2A13 Media Flow Direction

This TLV defines the media flow direction.

Used in:
0x0033 NPDI Universal ICB

Byte | Description
0, 1 | Tag 0x2A13
2, 3 | Length 0x0001
4 | Value 0xFF Invalid 0x00 Send and Receive (generates SDP line a=sendrecv) 0x01 Receive Only (generates SDP line a=recvonly) 0x02 Send Only (generates SDP line a=sendonly)

Tag-Length-Value block. A standardized block that allows data to inserted in a standard way into API messages.
Network Protocol Data Intelligence. Also called “Interworking,” it is a software product that operates within Excel’s Call Control (Layer 4) and Services (Layer 5) call processing layers. NPDI is meant to enhance Excel’s call processing product offering by allowing call processing layers (specifically Layers 4 and 5) to perform advanced analysis, generation, and conversion of Network Signaling (NS) Layer 3 information.
See Information Control Block.