Microsoft 1 manual Internet Messaging Access Protocol version 4 IMAP4, Joint Engine Technology JET

Glossary 105

Messaging service in Exchange 2000 uses a Microsoft published protocol called Rendezvous Protocol (RVP) while IMPP is being ratified

Internet Messaging Access Protocol version 4 – IMAP4

A standard-based protocol for accessing mailbox information. IMAP4 is considered

to be more advanced than POP3 because it supports basic online capabilities and access to folders other than the Inbox. Exchange Server 5.x and Exchange 2000 both support IMAP4.

Joint Engine Technology – JET

Defines the low-level access to underlying database structures in Exchange Server 4.0 and

5.0.JET was superceded with the Extensible Storage Engine (ESE) in Exchange Server 5.5 and Exchange 2000.

Lightweight Directory Access Protocol – LDAP

A standards-based protocol that can be used to interact with conformant directory ser- vices. LDAP version 2.0 allows for reading the contents of a directory database, whereas LDAP version 3.0 (defined under RFC2251) allows users and applications to both read and write to a directory database. LDAP was developed by Tim Howes and the University of Michigan.

Link State Algorithm – LSA

The algorithm used to propagate routing status information between servers running Exchange 2000. Based on ‘Dijkstra’s algorithm’, link state information is transferred between routing groups using the X-LINK2STATE command verb over Simple Mail Transfer Protocol (SMTP)SMTP and within a routing group using a Transmission Control Protocol (TCP) connection to port 691.

Mail-based replication – MBR

A mechanism to replicate directory information through a messaging transport. This term applies to Exchange 5.x inter-site directory replication, and additionally, Active Directory replication through SMTP.

MD (Message Digest Algorithm, MD4, MD5)

Developed by Rivest, this takes a message of arbitrary length and produces a 128-bit message digest. The algorithm is optimized for 32-bit machines. Description and source code for MD4 and MD5 can be found as Internet RFCs 1319 – 1321.

MDB

An instance of a database implemented in Exchange server. A single MDB is normally identified as being public or private depending on the type of data that it stores. A single server running Exchange 2000 can accommodate up to 20 active MDBs.

Message Transfer Agent – MTA

The component in all versions of Exchange Server that transfers messages between servers using the X.400 protocol.