Configuring Isdn Channel Bonding Settings For Downspeeding - Cisco 3521 Administrator's Manual

Chapter 3 Configuring the Cisco IPVC 3500 Series Gateway
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Configuring ISDN Channel Bonding Settings for Downspeeding

In the Bonding section of the Settings tab, you can configure ISDN channel bonding parameters that
affect downspeeding functionality. Downspeeding is the ability to complete and maintain a call when
ISDN conditions are bad. In downspeeding, call capabilities are automatically renegotiated when a call
fails. Downspeeding contributes to a higher percentage of call completion on the network. The
Cisco IPVC 3500 Series Gateway supports downspeeding at call setup and in mid-call.
With downspeeding, when connection problems occur at call setup, the gateway attempts to connect a
call at a lower bit rate than that requested. Administrators can configure the gateway to attempt to
connect a video call at a specified minimum bit rate, or to attempt to connect the call as a voice call.
In downspeeding, when connection problems occur in mid-call, the gateway attempts to connect a video
call at the specified lower bit rate. When downspeeding is complete and the call is connected at the
specified lower bit rate, the gateway notifies the Internet Protocol (IP) endpoint of the new call rate.
Procedure
In the Gateway interface, on the sidebar, click Gateway (if not already selected).
Step 1
Step 2 Click the Settings tab.
Step 3 Click the Bonding button.
Step 4 Select the Enable bonding check box to enable ISDN bonding support.
In the Maximum B channels for bonded call field, choose the maximum number of B channels—3, 4,
Step 5
5, 6, 8, 12, 23, or 30—that you want to allow for a single bonded call. The default setting for BRI
gateways is 8. The default setting for PRI gateways is 30.
When the number of B channels required to process a bonded call exceeds the number specified in this
field, the gateway performs downspeeding as shown in
Table 3-4
Call Direction
IP (LAN) to WAN
(ISDN)
IP (LAN) to WAN
(ISDN)
WAN (ISDN) to
LAN (IP)
WAN (ISDN) to
LAN (IP)
Administrator's Guide for Cisco IPVC 3521 BRI Gateway, Cisco IPVC 3526 PRI Gateway, and Cisco IPVC 3540 PRI Gateway
OL-7995-01
Select the Enable T.120 check box to enable transparent support for T.120 capabilities.
Select the Enable FECC check box to enable transparent support for Far End Camera Control
(FECC) capabilities.
Downspeeding Policy Operation
Downspeed Advanced
Command Parameter
enable (default)
disable
enable (default)
disabled
Configuring Gateway Settings
Table 3-4.
If Call B Channels Exceed the Maximum:
Gateway tries to call at the maximum number
of B channels.
Call disconnects.
Call disconnects.
Call disconnects.
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