Connecting simplex and duplex channels

Applications create end-to-end media channels by joining pairs of endpoints with simplex channels or duplex channels to the same endpoint. You can configure the flow of data through a connection in the following ways:

Connection

Description

Simplex

Create simplex connections by creating simplex channels (encode or decode) and connect them with the appropriate endpoints. The connection carries data in a single direction.

Symmetrical duplex

Create duplex connections by creating duplex channels of the same type (encode and decode) and connect them with the appropriate endpoints. The connection carries data in two directions.

Asymmetrical duplex

Create a simplex encode channel of one type (for example, G.711 or G.723), a decode channel of another type (for example G.729A or G.726), and connect them both to the same endpoints. Each connection carries data in a different direction (and possibly encoded according to a different algorithm), but together the connections make up a full duplex data path.

RTP multiple unicast

Create a series of RTP simplex send endpoints (up to eight) and connect all of the these RTP endpoints to a DS0 endpoint through a voice encoder channel.

For example, in the following illustration the application creates an asymmetric duplex connection between RTP simplex endpoints (IPv4 or IPv6) and a DS0 endpoint by creating a simplex G.723.1 encode connection in one direction, and a simplex G.711 decode connection in the opposite direction. Since both connections share the same endpoints, data flowing across the channel is encoded and/or decoded according to a different algorithm, depending on the direction in which it flows. The following illustration shows a pair of asymmetrical MSPP simplex connections: