Microsoft Exchange 2000 Operation Manual page 114

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Microsoft Exchange 2000 Operations Guide — Version 1.0
Messaging Application Programming Interface – MAPI
The API that is used by Microsoft messaging applications such as Outlook to access
collaboration data. MAPI, or more specifically, MAPI Remote Procedure Calls (RPC), is
also used as the transport protocol between Outlook clients and servers running Exchange.
Metabase
A store that contains metadata such as that used by Internet Information Server IIS to
obtain its configuration data. The metabase can be viewed through utilities such as
Metaedit.
Metabase update service
A component in Exchange 2000 that reads data from Active Directory and transposes it
into the local IIS metabase. The metabase update service allows the administrator to make
remote configuration changes to virtual servers without a permanent connection to each
system.
Metadata
Data about data. In relation to Exchange, this term can be used in the context of Active
Directory, but can also be used to describe the structure within the store or the MTA.
Mixed-vintage site (also known as "PtOz")
An Exchange 5.x site that also contains servers running Exchange 2000.
Multipoint Control Unit – MCU
A reference to the T.120 protocol that allows clients to connect to data conferencing
sessions. MCUs can communicate with each other to transfer conferencing information.
Name Service Provider Interface – NSPI
Part of the DSProxy process that can accept Outlook client directory requests and pass
them to an address book provider.
Namespace
A logical collection of resources that can be managed as a single unit. Within Active
Directory, a domain defines a namespace.
Naming context
A self-contained section of a directory hierarchy that has its own properties, such as
replication configuration and permissions structure. Active Directory includes the domain,
configuration, and schema naming contexts. Exchange Server 5.5 also uses naming con-
texts; Organization, Address Book Views, Site, Configuration, and Schema.
Network News Transfer Protocol – NNTP
A standards-based protocol that includes simple command verbs to transfer USENET
messages between clients and servers, and between servers. NNTP uses Transmission
Control Protocol/Internet Protocol (TCP/IP) port 119.