Sidewinder G2 6.1.2 Administration Guide - Glossary of Technical ...

Configuring the H.323 Filter tab
Chapter 6: Configuring Application Defenses
Creating Multimedia Application Defenses
This tab allows you to select H.323 codecs you will allow your users to access.
You can select from the following options:
• Required—Select this option to allow only the codecs required by H.323 for
compliance.
• Required + Low Bandwidth Audio—Select this option to allow the required
H.323 codecs as well as low bandwidth options.
• Required + All Audio—Select this option to allow all H.323 codecs except
the codecs that allow video.
• Required + All Audio + Video—Select this option to allow all available
H.323 codecs.
• Custom—Select this option to specify which codecs you want to allow. To
allow a codec, select the appropriate check box. A check mark appears in
the corresponding check box when a codec is allowed.
• Select All—Click this button to select all of the H.323 codecs (all codecs will
be selected).
• Deselect All—Click this button to deselect all of the H.323 codecs (all
codecs will be deselected).
Note: If you select an option other than Custom and then make modifications to
the selected codecs, the Custom option will automatically become selected.
The following list provide an example of codecs commonly used by Microsoft’s
NetMeeting:
• G.711—The G.711 codec options can transmit audio at 48, 56, and 64 kB
per second (kBps). Select this codec for audio that is being passed using
high speed connections.
• G.723—The G.723 codec options determine which format and algorithm will
be used for sending and receiving voice communications over a network.
This codec transmits audio at 5.3 and 6.3 kBps, which will reduce
bandwidth usage.
• H.261—The H.261 codec will transmit video images at 64 kBps (VHS
quality). Select this codec for video that is being passed using high speed
connections.
• H.263—The H.263 codec determines which format and algorithm will be
used to send and receive video images over a network. This codec
supports common interchange format (CIF), quarter common interchange
format (QCIF), and sub-quarter common interchange format (SQCIF)
picture formats. It is also a good match for Internet transmission over lowbit-rate
connections (for example, a 28.8 kBps modem).
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