When you use SIP, you can use the URI format to address an end user. Intercluster URI calls are routed based on the host part of a URI. Therefore, each cluster must use a different URI host part. GDPR, an ILS application, provides a mechanism that allows the same host part to be used in URIs across clusters by exchanging URI call-routing information across clusters.
The dial plan implementation in large deployments with lots of Cisco Unified Communications Manager clusters is complex and time-consuming. GDPR substantially simplifies dial plan implementation in large Cisco Unified Communications Manager deployments because it allows clusters to exchange numbers, patterns, and PSTNfailover call-routing information.
In this section, we describe the purpose of ILS and GDPR, the services they provide, and how they are implemented.