Configuring Pstn Fallback - AudioCodes E-SBC User Manual

CHAPTER 39 CRP Configuration
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Configuring PSTN Fallback

You can enable the CRP to route emergency calls (or PSTN-intended calls) such as "911" from the
Proxy server (IP Group #2 "CRP Proxy") to the PSTN (IP Group #3 "CRP Gateway"). In addition,
for calls from the Proxy server to Users (IP Group #1 "CRP Users"), the device searches for a
matching user in its Users Registration database and if not located, it sends the call to the PSTN
(IP Group #3 "CRP Gateway") as an alternative route.
➢
To enable CRP Gateway fallback:
1. Open the SBC General Settings page (Setup menu > Signaling & Media tab > SBC folder >
SBC General Settings).
2. From the 'CRP Gateway Fallback' drop-down list, select Enable.
3. Click Apply; the alternative routing rule is added to row index #7 ("CRP Proxy" to "CRP
Gateway" routing) in the IP-to-IP Routing table.
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The destination for the routing rule at Index 2 is the source IP Group (i.e., from
where the REGISTER message is received).
Routing rule at Index 7 appears only if the CRPGatewayFallback parameter is
enabled (see Configuring PSTN
Enabling this feature (this routing rule) may expose the device to a security "hole",
allowing calls from the WAN to be routed to the Gateway. Thus, configure this
feature with caution and only if necessary.
This PSTN routing rule is not an alternative routing rule. In other words, if a match
for a user is located in the database, this PSTN rule will never be used regardless
of the state of the user endpoint (e.g., busy).
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Fallback).
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