All channels on both sides of the R2MFC MBM are bidirectional: they accept both incoming and
outgoing calls. If unidirectional trunks are used, the direction is handled by the far ends (BCM and
CO); the direction need not be configured in the R2MFC MBM.

In order to handle bidirectional calls, and eliminate internal collisions (when both sides originate a
call on the same channel simultaneously), the R2MFC MBM allows flexible channel
inter working; calls originating on a channel can use any free channel on the opposite side.

On incoming calls to the BCM, the far-end (for example, CO switch) selects the MFC channel.
The R2MFC MBM presents the call to the BCM by PRI and allows the BCM to determine which
channel to use.

On outgoing calls, the BCM selects on which PRI channel the call starts. The R2MFC MBM
selects a free MFC channel, and originates the outgoing call on it. For this purpose, the R2MFC
MBM supports 3 search methods to select a free MFC channel:

•

Round robin (default)

•

Linear ascending

•

Linear descending

The MFC channel selection method can be modified through the CLI. See

Chapter 7, “Command

Line Interface (CLI),” on page 73

for commands available through the CLI.