Suppression Of Dtmf Forwarding; Star Cascading Topology; Master-Slave Cascading - Polycom 1500 Administrator's Manual

RealPresence Collaboration Server (RMX) 1500/1800/2000/4000 Administrator's Guide

Suppression of DTMF Forwarding

Forwarding of the DTMF codes from one conference to another over an ISDN cascading link is not
automatically suppressed as with IP cascading link and it can be limited to basic operations while
suppressing all other operations by a system flag: DTMF_FORWARD_ANY_DIGIT_TIMER_SECONDS.
System Flag Settings
The DTMF_FORWARD_ANY_DIGIT_TIMER_SECONDS flag determines the time period (in seconds) that
MCU A will forward DTMF inputs from conference A participants to MCU B.
Once the timer expires, most of the DTMF codes (excluding five operations as for IP links) entered in
conference A will not be forwarded to conference B. This is done to prevent an operation requested by a
participant individually (for example, mute my line) to be applied to all the participants in conference B.
Flag range (in seconds): 0 - 360000
This flag is defined on MCU A (the calling MCU).
If a flag is not listed in the System Flags list it must be added to the system.cfg file before it can be modified.
For more details on defining system flags, see

Star Cascading Topology

In the Star topology (as well as in the Basic topology), the MCUs are usually installed at different locations
(states/countries) and participants connect to their local MCU to facilitate the connection and save long
distance call costs. Star Topology Cascading requires that all cascaded MCUs reside on the same network.
Although participants in Star Cascading conferences can connect to their local conference using IP
(H.323, SIP) and ISDN, the Cascading Links between conferences must connect via H.323.
Content sharing is available to all conferences over the H.323 Cascading Link.
In this topology, the MCUs are networked together using two modes:
● Master-Slave Cascading
● Cascading via Entry Queue

Master-Slave Cascading

It is similar to MIH (Multi Hierarchy) cascading, with only two levels: one Master MCU on level 1 and several
Slave MCUs on level 2.
The cascading hierarchy topology can extend to four levels
Configuration ) and should be deployed according to the following guidelines:
● If an Collaboration Server is deployed on level 1:
 Collaboration Server systems can be used on level 2
 MGC with version 9.0.4 can be used on level 2 if Collaboration Server version 7.0.2 and higher is
deployed in level 1
Polycom®, Inc.
Modifying System Flags
(MIH Cascade - a Sample 3-Level Cascading
on page 745.
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