Multipoint Calls And Firewall Information - Polycom ViewStation FX4000 User Manual

ViewStation FX/VS4000 User Guide

Multipoint Calls and Firewall Information

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the current conference speed and admitted into the conference (rate
matching).
However, if one of the systems cannot downspeed, the conference is
kept at the original data rate, while the incoming call keeps its own
data rate. The system with the lower data rate can send and receive
audio. It can also send video, but cannot receive video. For example,
if a system that is not capable of downspeeding connects at 384
kbps, the conference proceeds at 384 Kbps and admits the new
endpoint at 128 Kbps. The 128 Kbps endpoint will be able send and
receive audio. It can also send video, but it cannot receive video. It
can only see its own video instead.
To indicate that a particular endpoint which cannot downspeed at
the correct data rate is admitted to the multipoint call as an audio
call only, the ViewStation FX or VS4000 MCU displays a picture of a
telephone in the screen area corresponding to that endpoint call.
Downspeeding calls, either IP or ISDN, to allow another endpoint to
be added to an existing call (Dial-In Calling) is supported for mixed
protocol calls with systems that are capable of downspeeding. For
more information about inbound calls, refer to
page 237. For mixed protocol calls, see
page 224.
For a 2 or 3-way conference, the maximum allowable downspeeding
rate is 512 Kbps. For a 4-way conference, the maximum allowable
downspeeding rate is 384 Kbps.
The following information specifies how many TCP and UDP ports
need to be opened through a firewall for multipoint calls.
The port assignment is defined in the Firewall & LAN Connection
screen, under Use Fixed Ports.
Note
Dial-In Calling, on
Mixed Protocol Dialing, on
www.polycom.com