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5.4 MVIP Switch Model

The AG Connect board switch model (shown in Figure 5) is a standard MVIP switch model, with provisions for routing voice and signaling information to and from the line interfaces and for setting up conferencing, if the board model supports this feature. (For more information about MVIP switch models, see Getting Started With MVIP Switching.)
The specific model parameters for the AG Connect board are as follows: Streams 0...15, each with timeslots 0...31, are connected to the MVIP bus. The first 8 streams are "forward" streams. The second 8 are "reverse" streams. Streams 16 and 17 are local streams, carrying voice and signaling information for the line interfaces. Stream 16 carries voice information, and stream 17 carries the signaling information. The line interfaces are accessed via the timeslots 0...23. Each line interface n is assigned timeslot number (n-1). For example, the voice information for the first line interface on the board is carried on Stream:Timeslot 16:0. The signaling information for the second line interface is carried on Stream:Timeslot 17:1. Stream 18 is reserved for line interface configuration. Applications should not access timeslots on stream 18. Stream 19 is a local stream. It is reserved for future use. (Conferencing boards only) Streams 20...40, each with timeslots 0...31, are available for conferences. A maximum of 16 conference seats are available. For more information, see section 5.5. . Figure 5. MVIP Switching Model For AG Connect Board

5.4.1 Switching Restrictions On MVIP Streams

MVIP data streams (DSi and DSo) are paired on a timeslot-by-timeslot basis. During any particular timeslot on a given MVIP stream pair (DSin and DSon), you may either read DSon and write DSin (a "forward" connection) or read DSin and write DSon (a "reverse" connection). You cannot simultaneously read DSin and DSon, nor simultaneously write DSin and DSon.
Making a connection of any type involving a timeslot on an MVIP stream establishes the direction for that timeslot pair. The direction may not be changed until all connections involving the timeslot have been broken.
For example, if you establish a simplex connection from 8:0 to 16:0, you specify that timeslot 0 in this stream is configured in a reverse connection (by specifying stream 8 instead of stream 0). From then until you break this connection (by disabling output on 16:0), performing any of the following operations with Stream:Timeslot 0:0 will cause an error: Sampling input on 0.0. However, you may sample input on 8:0. Sending a pattern on 0:0. However, you may send a pattern on 8:0. Making further connections (broadcast) from 0:0 to other timeslots. However, you may broadcast from 8:0 to other timeslots. Making a connection to 0:0. However, you may make a connection to 8:0.
Note that there is no direction associated with local streams.
These switching restrictions are referred to as "switch blocking" in the MVIP-90 Standard, Release 1.1 manual.

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