Developer Guide for SIP Transparency and Normalization
Pre-Loaded Scripts
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Preloaded Scripts

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Preloaded Scripts


Preloaded Scripts


Preloaded scripts are Lua scripts that are provided as part of a Cisco Unified Communications Manager (Unified CM) basic installation. The preloaded scripts are automatically available when you upgrade to (or install) Unified CM Release 8.6 or a later release. These scripts normally have transparency- and normalization-related Lua code that you can use for a particular feature and are named with an easy-to-follow naming convention.

The administrator can select the preloaded scripts on the SIP Trunk Normalization Script drop-down menu. To add additional transparency- or normalization-related changes to a preloaded script, copy the content of the preloaded script and create a new script with the copied content plus additional desired changes.

The following preloaded scripts are provided with Unified CM Release 9.0 and later releases:

Refer-passthrough—Used to pass through an inbound in-dialog REFER (without Replaces) message to the other side of a call arc, if it is a SIP trunk.The Lua script will copy the Refer-To and Referred-By headers from the inbound REFER message and save them in the transparency object.

HCS-PCV-PAI-passthrough—This script is used to:

Pass through a P-Charging-Vector header for INVITE, UPDATE, and 200 OK

Use the configured term-ioi while adding the P-Charging-Vector to 200 OK

Pass through a P-Asserted-Identity header for INVITE

vcs-interop—Used to allow proper interoperation between Unified CM and VCS. This script specifically handles the differences in how the two nodes support SRTP and will change the right side of URIs in the From, Remote-Party-Id and P-Asserted-Id headers to use the configured top-level domain instead of the IP address of Unified CM.

diversion counter—Used to handle the diversion counter parameter for call forward and diversion scenarios. This script should be attached to both the incoming and outgoing trunks. If there is a call diversion or call forward within the cluster, then this script will adjust the counter parameter in the outgoing diversion header. If there is no call forwarding within the cluster, then this script will simply pass through the counter parameter from the inbound to the outbound side. For more information about the diversion counter script, see Diversion Counter.