AudioCodes Mediant 500L - Configuring PSTN Fallback

User's Manual 776 Document #: LTRT-10532
Mediant 500L Gateway & E-SBC
Mode Index Source IP
Group
Request Type Destination
Type
Destination
IP Group
Destination
Address
Alternative
Route Options
8 #3 [CRP
Gateway]
All IP Group #2 [CRP
Proxy]
- Route Row
9 #3 [CRP
Gateway]
All IP Group #1 [CRP
Users]
- Alternative
Route Ignore
Inputs
Note:
• 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 on page 776).
41.5 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) to the PSTN (IP Group 3). In addition, for calls from the
Proxy server to Users (IP Group 1), the device searches for a matching user in its Users
Registration database and if not not located, it sends the call to the PSTN (IP Group 3), as
an alternative route.
To enable this feature, set the ini file parameter CRPGatewayFallback to 1. When enabled,
the alternative routing rule appears immediately below the IP Group 2 to IP Group 1 rule in
the IP-to-IP Routing table.
Note:
• 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).