Appendix A: Glossary

Microsoft Office Communications Server 2007 and Microsoft Office Communications Server 2007 R2 will reach end of support on January 9, 2018. To stay supported, you will need to upgrade. For more information, see Resources to help you upgrade your Office 2007 servers and clients.

Term Definition

A/V Authentication Service

A service that authenticates media transactions originating outside the enterprise firewall. The A/V Authentication Service is collocated on the Audio/Video Edge Server.

Address Book Service

A service that runs on an Office Communications Server Front End Server and daily synchronizes phone numbers on the client with refreshes from Active Directory.

Advanced Media Gateway

A PSTN gateway that tightly integrates the functionality of the Basic Media Gateway with the signaling and media translation services of the Mediation Server in a single piece of hardware.

Audio Conference Provider

A third-party telephony provider that enables conferencing on legacy PBX systems.

Audio/Video Edge Server

An Office Communications Server that resides in the perimeter network and provides a trusted point through which media traffic can traverse firewalls.

Auto Attendant

A set of voice prompts that gives external users access to the Exchange 2007 Unified Messaging system. An auto attendant lets the user use either the telephone keypad or speech inputs to navigate the menu structure, place a call to a user, or locate a user and then place a call to that user.

Basic Hybrid Media Gateway

A PSTN gateway collocated with Mediation Server on a single computer. The functionality of gateway and Mediation Server are separate, just as they are with a basic media gateway, but they are collocated on a single piece of hardware rather than deployed on separate ones.

Basic Media Gateway

A PSTN gateway that uses SIP and RTP to communicate with a Mediation Server, and various telephony signaling and media protocols to communicate with the PSTN (or a PBX).

Call Forwarding

The process of automatically forwarding a missed call to a user-designated number, which can be another user, a PSTN number, or voice mail. In Enterprise Voice, call forwarding consists of sending a SIP INVITE to the designated number.

Call Notification

The process of alerting a user that a call has been received. In Enterprise Voice, the alert is typically in the form of e-mail from Exchange UM.

Call Route

A named association of a defined set of target numbers, one or more gateways, and one or more phone usage records. An Enterprise Voice call route specifies the gateways to which target numbers matching a certain pattern are to be directed and the permissions that a caller must have to make calls that use the route.

Departmental Deployment

An Enterprise Voice deployment in a department or workgroup within an organization where other users remain deployed on a legacy PBX. In a departmental deployment, a user is enabled either for Enterprise Voice or the PBX, but not both, as is the case with PBX Integration.

Dial Plan

The expected number and pattern of digits in telephone numbers for a given location. For instance, the North American Numbering Plan (NANP) uses a 10-digit dial plan that includes a 3-digit area code and a 7-digit telephone number. Also see Exchange UM Dial Plan.


A standard industry format for number normalization. The E.164 format consists of a country code (1–3 digits) and a National Significant Number (12–14 digits). Excluding prefixes, E.164 numbers cannot exceed 15 digits.

Enterprise Voice

Microsoft's SIP-Powered VoIP Solution. An implementation of VoIP telephony based on the industry standard SIP protocol.

Exchange UM Dial Plan

A data structure in Exchange that maps Communications Server users to a particular set of UM servers and assigns configuration parameters to that set of users and servers.

Exchange Unified Messaging

An Exchange Server 2007 server role that combines voice messaging, fax, and e-mail into one Inbox, which can be accessed from the telephone and the computer. Exchange UM can be configured to provide voice mail and other services to Enterprise Voice deployments where such services are not already provided by a PBX.

Greenfield Deployment

An Enterprise Voice deployment in an environment where no legacy PBX system exists. A new company or a new facility are typical examples.

Hunt Group

A group of PBX resources or extension numbers that are shared by users. A hunt group is used by Exchange UM to efficiently distribute calls into or out of a given business unit or set of Enterprise Voice users.

Inbound Routing

A component on the Communications Server Front End Server that manages the routing of calls received by Enterprise Voice users.

IP Telephony

A telephony system in which signaling and media are carried over an IP network. In other words, VoIP.


A PBX that has a network adapter and is capable of sending and receiving data packets over the Internet, including VoIP calls.

Location Profile

A location profile defines all phone numbers that can be dialed from a named location. A location contains one or, typically, more normalization rules.

Media Gateway

A device that connects the PSTN to your LAN. A media gateway translates both signaling and media between an Enterprise Voice infrastructure and the PSTN or a legacy PBX.

Mediation Server

An Office Communications Server that translates signaling and media for calls (SIP transactions) flowing between Communications Server and a media gateway connected to the PSTN. A Mediation Server combined with a Basic Media Gateway is required for PSTN connectivity. An advanced media gateway integrates the functionality of gateway and Mediation Server in a single piece of hardware.

Normalization (phone number)

The process of converting user phone numbers in various formats to a numeric string of uniform format. The format used by Enterprise Voice is E.164.

Normalization Rule

A regular expression that specifies how to convert phone numbers following a particular pattern to E.164 format.

PBX Integration

An Enterprise Voice deployment that coexists with an IP PBX such that users are enabled on both systems, and each system forks incoming calls to the other.

Phone Usage Record

In Enterprise Voice, an arbitrary label that identifies a collection of routes. Examples include Local, Area Code, State, Province, USA, Singapore, and International.

Primary Phone Number

A user's primary work number as specified in the Active Directory msRTCSIP-line attribute. Communications Server performs reverse number lookup on a user's primary phone number to obtain all the users SIP endpoints.


Public Switched Telephone Network. The traditional worldwide circuit-switched telephone network.

Real-time Transport Protocol (RTP)

A standardized format for delivering audio and video over the Internet.

Remote Call Control

The ability to manage and control a PBX phone using a CSTA (Computer Supported Telecommunications Application) such as Office Communicator.

Remote Worker

An external user with a persistent Active Directory identity within the organization.


See Call Route.


Real-time Transport Protocol.

Secure Real-time Transport Protocol (SRTP)

A form of RTP designed to provide encryption, authentication, and data integrity for media packets carried over the Internet.

Session Initiation Protocol (SIP)

An IETF (Internet Engineering Task Force) signaling protocol for real-time communications, including IM, multimedia conferencing, and VoIP. Communications Server and Enterprise Voice use SIP as the standard signaling protocol.


Session Initiation Protocol.

SIP Endpoint

A device that terminates a SIP transaction; an end node in a SIP network. In Communications Server, a user's SIP endpoints are all the devices on which a user can receive A SIP INVITE request.


A software application, such as Office Communicator, that can act as a telephone in a VoIP network.


Secure Real-Time Transport Protocol.

Subscriber Access

An Exchange UM service that provides dial-in access for company users.


Time-division multiplexing, a method for sending multiple signals over a single phone line. A TDM PBX lacks a network adapter and cannot pass IP packets. For these reasons a TDM PBX cannot be enabled to integrate with Enterprise Voice.

UM IP Gateway

An Exchange UM Active Directory container object that represents a physical media gateway separating Exchange UM and Enterprise Voice.

UM SIP Dial Plan

An Exchange UM Active Directory container object that logically represents the set of extension numbers shared by a group of Enterprise Voice users.

Unified Communications

Microsoft's software-powered, user-centered, multimode communications solution. Unified Communications enables a user to send IM, view presence data of contacts, participate in real-time conferences, and place calls using VoIP from a desktop computer or other client device.

Voice Policy

A named set of Phone Usage Records. A voice policy defines call privileges for one or more users.


Voice over Internet Protocol.