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Call Server Configuration
Polycom, Inc. 251
See also:
Dial Rules on page 239
The Default Dial Plan and Suggestions for Modifications on page 241
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 page 255 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).
Resolve to external address Determines if the dial string is a well-formed instance of an external address type to
which the rule applies, and if so, uses the resolution procedures specified in the
applicable standard for that address type.
After selecting this action for a rule, select the address type or types to which the
rule applies. The address types and applicable standards used to resolve them
are:
• SIP URI: RFCs 3261 and 3263
• H.323 Email-ID: H.225.0 specification, Appendix IV
• H.323 url-ID: H.323 specification, Annex O
Resolve to conference room
ID
Looks for a conference room (virtual meeting room, or VMR) that matches the dial
string.
Resolve to virtual entry
queue
Looks for a shared-number entry queue that matches the dial string.
Variable Initial value
CALLER_E164 For H.323 calls only, an 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. Blank otherwise.
For this action: The system attempts to resolve the address as follows: