A Logical-host is a database configuration of related resources. Each TDP can use the resources of only one Logical-host. A Logical-host is identified by a Host Number, an arbitrary number between 1 and 1023. Each also has a Host Type, which identifies client characteristics (such as a default character set type and the structure of numeric data). For IBM mainframes the Host Type is designated by 'IBM', which is assigned the value zero. The Host Number is added to the Host Type to create a Logical-host id. TDP is informed of the Logical-host id when it establishes communication with the database.
Channel Processors (CPs), Network Processors (NPs), and Session Processors (SPs) are resources associated with a Logical-host. If a TDP is to use a Logical-host, then at least one CP or NP, and SP must be associated with that Logical-host. CPs, NPs, and SPs are discussed in the subsequent sections. See Teradata® Tools and Utilities for IBM z/OS Installation Guide (B035-3128) for more information on configuring a Logical-host and its resources.