CHAPTER39 CRP Configuration
Mediant 1000 Gateway & E-SBC | User's Manual
● 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 Fallback).
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.
● 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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