DMA OperationsGuide Preliminary/Postliminary Scripting
254 Polycom, Inc.
Preliminary/Postliminary Scripting
A preliminary is an executable script, written in the Javascript language, that
defines processing actions (filtering or transformation) to be applied to a dial
string before the dial rule’s action is performed.
A postliminary is an executable script, written in the Javascript language, that
defines dial string transformations to be applied before querying an external
device (gatekeeper, SIP peer, SBC, or MCU).
Transformation scripts output some modification of the DIAL_STRING
variable (which is initially set to the dial string being evaluated).
Filtering scripts may pass the dial string on to the dial rule’s action (if the filter
criteria aren’t met) or return one of the following:
•NEXT_RULE: Skips the rule being processed and passes the dial string to
the next rule.
•BLOCK: Rejects the call.
See “Sample Preliminary and Postliminary Scripts” on page258 for some
examples.
The following table describes the predefined variables you can use in a
preliminary or postliminary script. The script can evaluate a variable or
change its value (the change isn’t preserved after the script completes).
Table10-10 Predefined variables for preliminary and postliminary scripts
Variab le Initial value
CALLER_E164 Array variable initially set to the set of E.164
addresses of the caller. The length of the array is 0
if the caller doesn’t have an E.164 address.
CALLER_H323ID Array variable initially set to the set of H323ID
addresses of the caller. The length of the array is 0
if the caller doesn’t have an H323ID address.
CALLER_IS_IPV6 “TRUE” if the caller is an IPv6 endpoint. “FALSE”
otherwise.
CALLER_SIP_URI Array variable initially set to the set of SIP URI
addresses of the caller. The length of the array is 0
if the caller doesn’t have a SIP URI address.
CALLER_SITE_AREA
_CODE Area code of the caller’s site. Blank if the site
doesn’t have an area code.
CALLER_SITE_COUNTRY
_CODE Country code of the caller’s site. Blank if the site
doesn’t have a country code.
CALLER_SITE_DIGITS The number of subscriber number digits in the
caller’s site (that is, the length of a phone number at
the site, excluding area code). or Blank if the site
doesn’t have a number of digits.