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CHAPTER 25 Routing SBC
Mediant 4000 SBC | User's Manual
Parameter Description
Note:
■ The parameter can be used for normal and alternative routing.
■ The response code for redirect messages can only be 3xx.
Configuring Rerouting of Calls to Fax Destinations
You can configure the device to reroute incoming SBC calls identified as fax calls to a new IP
destination. The device identifies a fax call if it detects, within a user-defined interval, a calling
(CNG) tone on the originator side (incoming IP leg). If the device detects a fax call, it terminates the
call and reroutes it using a new INVITE to the new fax destination (new IP Group). If the initial
INVITE that was used to establish the voice call was already sent, the device sends a CANCEL (if
not connected yet) or a BYE (if already connected) to release the call (with the internal disconnect
reason RELEASE_ BECAUSE_ FAX_ REROUTING, translated to Q.850 reason GWAPP_
NORMAL_UNSPECIFIED 31).
● You must configure the originating fax to use the G.711 coder.
● If the remote side replies with T.38 or G.711 VBD, fax rerouting is not done.
● If both fax rerouting and fax re-INVITE are configured, only fax rerouting is done.
The following provides a basic example on how to configure fax rerouting.
➢
To configure fax rerouting:
1. Open the Fax/Modem/CID Settings page ( Setup menu > Signaling & Media tab > Media
folder > Fax/Modem/CID Settings ).
a. In the 'Fax Detection Timeout' field [SBCFaxDetectionTimeout], enter the duration (in
seconds) for which the device attempts to detect fax (CNG tone):
b. From the 'CNG Detector Mode' drop-down list [CNGDetectorMode], select Event Only .
2. Load an ini file to the device through the Auxiliary Files page (see Loading Auxiliary Files
through Web Interface on page 664) with the following parameter setting, which enables in-
band network detection related to fax:
EnableFaxModemInbandNetworkDetection = 1
3. In the IP Groups table (see Configuring IP Groups ), configure the following IP Groups:
● IP Group #0 "HQ": This is the source IP Group, sending voice calls and fax calls.
● IP Group #1 "Voice": This is the destination for voice calls sent from IP Group #0.
● IP Group #2 "Fax": This is the destination for fax calls sent from IP Group #0.
4. For the fax destination (IP Group #2), do the following:
a. In the Coder Groups table (see Configuring Coder Groups ), configure a Coder Group with
T.38 to enable fax transmission over IP.
b. In the IP Profiles table (see Configuring IP Profiles ), configure an IP Profile:
i. From the 'Fax Coders Group' drop-down list, select the Coder Group that you
configured above.
ii. From the 'Fax Mode' drop-down list, select Handle always .
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