Using Dial Plan Tags For Routing Destinations - AudioCodes Mediant 4000 SBC User Manual

CHAPTER 20 SIP Definitions

Using Dial Plan Tags for Routing Destinations

You can use Dial Plan tags for determining the destination (IP Group) of an IP-to-IP Routing rule.
One of the benefits of using Dial Plan tags is that it can reduce the number of IP-to-IP Routing rules
that you would normally need to configure. For example, assume that you need to route calls from
IP Group "A" to two different IP Groups, "B" and "C", based on called (destination) prefix number
(e.g., 102 and 103). When not using Dial Plan tags, you would need to configure two IP-to-IP
Routing rules, where one rule sends calls with prefix number 102 to IP Group "B" and another rule
sends calls with prefix number 103 to IP Group "C". However, when using Dial Plan tags, you
would need to configure only a single IP-to-IP Routing rule whose destination IP Group is based on
a Dial Plan tag.
The following briefly describes the process for using Dial Plan tags in IP-to-IP Routing rules:
1. The device searches the Dial Plan Index, associated with the source IP Group of the incoming
SIP dialog, for a Dial Plan rule whose 'Prefix' parameter is configured with the same called
prefix number as the SIP dialog (e.g., 102). If found, the device inspects the tags in the 'Tag'
parameter (e.g., "Country=England;City=London;Essex") configured for that Dial Plan rule.
2. The device searches for a matching rule in the IP-to-IP Routing table and if the 'Destination
Type' parameter is configured to Destination Tag, it checks the tag name configured in the
'Routing Tag Name' parameter and compares it with the tags found in the Dial Plan rule. If the
'Routing Tag Name' parameter is configured as "default", the device selects the first tag name
in the Dial Plan rule that is configured without a value, for example, "Essex" (see Step 1). If the
'Routing Tag Name' parameter is configured with a specific tag name (e.g., "Country"), the
device selects the tag name with its value (e.g., "Country=England") in the Dial Plan rule.
3. The device searches the IP Groups table and IP Group Set table for an IP Group whose 'Tags'
parameter is configured with the same tag as selected from the Dial Plan rule. If found, the
device routes the call to this IP Group.
The following figure displays the device's SIP dialog processing when Dial Plan tags are used to
determine the destination IP Group:
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