The Configuration and Data Distribution Server, CDD Server, is a dedicated database server. A CDD Server is a necessary component in a network which includes several switches or TETRA Servers.
The CDD Server keeps track of user data across the network. In short:
Small networks with a single switch or TETRA Server do not need a separate CDD Server.
The CDD Server's counterparts in the TETRA system are
The switches in big TETRA networks have different roles. Some switches serve as home location registers (HLRs) and store the permanent user data. Other switches are visitor location registers (VLRs) and temporarily store the data on visiting users.
The CDD Servers work between the two types of switches – they are the database servers that make subscriber and talk group data accessible throughout the network.
As a result, any authorized dispatcher can get the necessary data on any user, regardless of their location in the network area.
The CDD Server is not involved in call setup.
Each CDD Server is fully duplicated.