Overview
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Selecting an appropriate User Integration model is key to implementing multi-cluster
successfully. An approach must be chosen to meet all user integration requirements.
Both methods require consideration for Directory integration requirements, which
are covered in detail. Several options are provided for both provisioning paradigms,
which the preferred deployment practice being to utilize CUCM’s LDAP Search feature.

Top-Down Syncs make VOSS-driven provisioning simpler, but current LDAP Server
functionality may not be sufficiently flexible to meet all customer LDAP integration
Requirements. Bottom-Up Syncs can work well when paired with Overbuild deployment
models, but careful consideration is needed for directory integration due to the
limited options afforded by Model Instance Filters.