AudioCodes Mediant 1000B User Manual page 736

Note: When tags are used in the IP-to-IP Routing table to determine destination IP
Groups (i.e., 'Destination Type' parameter configured to Destination Tag), the device
searches the Dial Plan for a matching destination (called) prefix number only.
The Dial Plan itself is a set of dial plan rules having the following attributes:

Prefix: The prefix is matched against the source and/or destination number of the
incoming SIP dialog-initiating request.

Tag: The tag corresponds to the matched prefix of the source and/or destination
number and is the categorization result.
You can use various syntax notations to configure the prefix numbers in dial plan rules.
You can configure the prefix as a complete number (all digits) or as a partial number using
some digits and various syntax notations (patterns) to allow the device to match a dial pan
rule for similar source and/or destination numbers. For more information, see the
description of the 'Prefix' parameter (DialPlanRule_Prefix) described later in this section.
The device employs a "best-match" method instead of a "first-match" method to match the
source/destination numbers to prefixes configured in the dial plan. The matching order is
done digit-by-digit and from left to right. The numbers are first matched to the rule
configured with the most constrained (specific) character set. Most constrained implies that
the dial plan pattern that has the fewest possible matches for a digit is matched first. For
example, if one rule contains the "x" wildcard character, which has ten possible matches
(i.e., 0-9) and another rule a specific digit (e.g., 4), the rule with the specific digit is selected
as the matching rule. The best match priority is listed below in chronological order:

Specific character (prefix)

Number range

"x" wildcard, which denotes any digit (0-9)

Suffix, where the longest digits is first matched. For example, ([001-999]) takes
precedence over ([01-99]) which takes precedence over ([1-9]).

. (dot), which denotes any character
For example, the table below shows the best match priority of an incoming call with prefix
number "5234":
Dial Plan
Prefix
523x
523([4]) or [(5234)]
523[2-6]
523.
5234
The following examples show how the best-matching method is done. Each example has
two dial plan rules which are shown listed in chronological order as they would be
configured in the table.

For incoming calls with prefix number "5234", the rule with tag B is chosen (more
specific for digit "4"):
User's Manual
Table 36-1: Dial Plan Best Match Priority
Best Match Priority (Where 1 is Highest)
Tag
A
A
A
A
B
736
Mediant 1000B Gateway & E-SBC
3
4
2
5
1
Document #: LTRT-27055