Live Communications Server 2005 Glossary

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Access Proxy
A Live Communications Server 2005, Access Proxy resides in the perimeter network, where it acts as a gateway between internal users and trusted remote users. The Access Proxy has two network addresses: a private address for the internal network and a public address for the external network. All external traffic passes through the Access Proxy before entering the internal network. Trusted external users include employees who are outside the internal network or located in branch offices, as well as users employed by federated partners. The Access Proxy authenticates remote servers, parses messages for validity checking, throttles connections, and blocks domains as configured by the administrator. See Federation, Private network address, Public network address, and Remote user.

Active Directory
The directory service included with Windows 2000 Server and Windows Server 2003. Live Communications Server uses Active Directory to store user and server information, including the server on which each user resides.

Allow and block list
A list of users who are allowed to, and blocked from, seeing presence information for other users of Microsoft Office Live Communications Server 2005. By default, all users can see presence information for all other users in a forest. Users can edit their own allow and block list to limit publication of their presence information, and administrators can edit allow and block lists to control the publication of presence information across an organization.

Application Manifest
An XML document defining a Microsoft SIP Processing Language (MSPL) application or a SIP application to Live Communications Server. An MSPL script is contained in a CDATA section within the Application Manifest itself. In a SIP application, the Application Manifest is incorporated in the compiled executable. See Microsoft SIP Processing Language and SIP Application.

Application Proxy
A Live Communications Server 2005, Proxy that hosts applications. The Application Proxy receives messages originating from within the organization's network, passes them to one or a succession of two or more of its hosted applications, which in turn filter or process the messages before passing them on. See Forwarding Proxy and Proxy.

Archiving agent
The component on each Live Communications Server that archives instant messages and dispatches them to the Archiving back end. Although the Archiving agent is installed on all servers, it must be explicitly enabled before archiving can commence. See Archiving back end and Archiving service.

Archiving back end
The logical entity that receives and stores instant messages sent by archiving agents from Live Communications Servers. The Archiving back end consists of the Archiving back-end queue and the Archiving back-end database. See Archiving back-end database and Archiving back-end queue.

Archiving back-end database
An SQL database for storing archived messages. Note: This database should not be confused with the Live Communications Server 2005, Back-End Database, which stores user information. See Back-End Database.

Archiving back-end queue
A MSMQ (Microsoft Message Queuing) infrastructure that receives messages from the Archiving Agent. The Archiving service reads messages from the queue and writes them to the Archiving back-end database. The queue and Archiving service can be located either on the same server as the Archiving back-end database or on a different server.

Archiving service
Live Communications Server 2005, Archiving service. Archives instant messages for organizations in need of compliance with government or corporate regulations or conducting usage analysis. Administrators can configure archiving to include all users, no users, or only certain users. The Archiving agent is installed by default on all Live Communications Server 2005 servers, but it must be enabled for archiving to occur. To archive a pool, archiving must be enabled for all servers in the pool.

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Back-End Database
The Live Communications Server 2005, Back-End Database. A SQL Server 2000 database containing user information for an Enterprise pool. The Back-End Database is hosted on a separate server and shared by all servers in the pool. Note: This database should not be confused with the Archiving back-end database, which stores archived instant messages.

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Clearing house
An organization that federates directly with multiple partners and serves to redirect traffic among them. In the typical default route configuration, the clearing house routes messages for all domains that are not explicitly configured by their administrators. The clearing house is trusted for all messages it sends to each domain. This configuration allows an organization to federate with a large number of partners without incurring the overhead of maintaining those connections. See Direct federation, Gated community, and Open clearing house.

Client
An application that initiates real-time communications and presents presence information on behalf of Live Communications Server users. See SIP client and Windows Messenger.

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Default route
When configured, the default route is used by an Access Proxy to route traffic to external domains for which direct federation or a gated community has not been defined.

Direct federation
A form of federation in which two organizations explicitly designate each other as trusted federated partners for purposes of exchanging instant messages and sharing presence information. Also known as direct peering or explicit peering. An organization can specify up to 300 federated partners for each Access Proxy deployed in its perimeter network.

Direct federation list
See Federated partner list and Federation.

Direct peering
See Direct federation.

Director
A Live Communications Server with no users hosted on it. The Director authenticates users and directs traffic to the appropriate server pool. It authenticates remote connections passed to it by the Access Proxy and eliminates the overhead of one pool having to forward traffic intended for another pool. In a typical deployment, the Director is the Access Proxy's internal next hop. Internal clients may also connect to the Director.

Domain Name System (DNS)
A hierarchical naming system used for mapping user-readable computer names to computer-readable IP addresses.

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Enterprise Edition
Live Communications Server 2005 Enterprise Edition. Enterprise Edition server consists of a pool of servers connected to a separate, shared SQL Server Back-End Database for storing user information. The servers in the pool function collectively as a single home server.

Enterprise pool
See Enterprise Edition.

Explicit peering
See Direct federation.

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Federated partner
An external organization with which you have established a direct federated connection. See Access Proxy and Federation.

Federated partner list
A list of federated domains that are authorized to connect to an organization through a particular Access Proxy. Each Access Proxy has its own list of federated partners; each federated partner can connect only through those Access Proxies where it is listed.

Federation
The ability to connect one Live Communications Server deployment to other Live Communication Server deployments in other organizations. Each federated partner deploys an Access Proxy, through which all SIP traffic crossing the network boundary is routed. The two most common types of federation are direct federation and clearing house. See Access Proxy, Direct federation, and Clearing house.

Flat-file logging
A feature of Live Communications Server 2005 whereby logged events can be written to and retrieved from a readable text file. See Logging.

Forwarding Proxy
A Live Communications Server 2005, Proxy that simply receives and forwards messages originating from within the internal network. A Forwarding Proxy is typically (but not exclusively) deployed in organizations or branch offices where no Enterprise pool is installed. The Forwarding Proxy forwards all outbound messages to an Access Proxy in the organization's perimeter network, which in turn passes them to internal Live Communications Servers. See Application Proxy and Proxy.

Front-end server
In Live Communications Server 2005 Enterprise Edition, a server that is deployed within the internal network but outside the Enterprise pool. Front-end servers include Access Proxy, Application Proxy, Forwarding Proxy, Director, and SIP/PSTN gateway. See Access Proxy, Application Proxy, Director, Forwarding Proxy, Front-End Server, and SIP/PSTN gateway.

Front-End Server
In Live Communications Server 2003 Standard Edition, a server that redirects incoming SIP requests to the appropriate home server. In Live Communications Server 2005, this role has largely been assumed by the Director. See Director, Front-end server, and Home server.

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Gated community
A closed community of federated organizations served by a single clearing house. The clearing house determines membership in the gated community. Individual members can choose to use the clearing house for all other members or can choose to federate directly with certain members but not others. Each member can also directly federate with other organizations outside the gated community. Federation with a member of the gated community, however, does not enable access to other members of the community. See Clearing house, Direct federation, and Open clearing house.

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Home server
A Live Communications Server on which a user is registered. Such a user is said to be hosted on that server. In addition to registering users, a home server routes SIP messages and maintains user data, such as contact lists, allow and block lists, and endpoints. A Standard Edition server functions as a stand-alone home server. It is functionally equivalent to a Live Communications Server 2003 Standard Edition home server. An Enterprise pool consists of multiple servers that function collectively as a single home server. See Enterprise Edition and Standard Edition.

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Instant Messaging (IM)
The ability of users to send and receive messages in real time. Windows Messenger is the recommended IM client for Live Communications Server 2005.

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Kerberos protocol
An authentication mechanism used by Live Communications Server to authenticate internal clients. The Kerberos protocol is not offered to external clients because they do not have access to internal domain controllers. See NTLM.

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Listening address
A number that enables IP packets to be sent to a particular process on a computer connected to the Internet. The default listening address for Live Communications Server is 5061.

Listening port
See Listening address.

Load balancer
Third-party hardware that balances IM traffic and, if necessary, routes it away from failed nodes. A Director passes incoming messages to the load balancer of the appropriate pool, which distributes them among servers in the pool. Load balancers can also be deployed with Access Proxies or other servers.

Logging
In Live Communications Server, logging is the recording of information about SIP traffic flowing through each server, events connected with server operations, and metadata related to the logging operation itself for the purpose of providing an audit trail, troubleshooting data, and information about system usage. This is distinct from the content archiving performed by the Live Communications Server 2005, Archiving service. See Archiving service and Flat-file logging.

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Microsoft SIP Processing Language (MSPL)
A scripting language for writing simple message filtering and routing applications. MSPL scripts run in the same process as Live Communications Server. See SIP Application.

Microsoft SQL Server 2000 Desktop Engine (MSDE 2000)
A desktop database engine based on Microsoft SQL Server 2000. Live Communications Server 2003 and Live Communications Server 2005 Standard Edition use MSDE 2000 to store user data, such as contact lists, allow and block lists, and endpoints.

Multiple points of presence (MPOP)
A feature whereby Live Communications Server 2005 can keep track of single user activity on multiple SIP clients? a desktop computer, telephone, and cellular phone, for example. See Presence.
Mutual TLS
See TLS.

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Next hop
From any given server in a network topology, the next server in line to which a message is routed.

NTLM
An authentication mechanism used by Live Communications Server to authenticate remote users who do not have access to internal Kerberos domain controllers. See Kerberos protocol.

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Open clearing house
Term used to distinguish a clearing house that is not a gated community. See Clearing house and Gated community.

Outside user
See Remote user.

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Pool
A collection of Enterprise Edition servers connected to a shared Back-End Database and functioning as a single home server. See Enterprise Edition and Enterprise pool.

Port number
See Listening address.

Prep domain
Prepares a domain for installation of Live Communications Server 2005. Creates six domain global groups and grants administrative credentials to the domain global groups on Live Communications Server objects using ACEs (access control entries).

Prep forest
Creates Live Communications Server objects in the forest root domain, including global settings container, global settings objects, and server container.

Prep schema
Extends the schema in Active Directory for Live Communications Server 2005. This is the first procedure that you need to run to prepare your enterprise for the first deployment of Live Communications Server 2005.

Presence
Information that describes whether a particular user is available to communicate in real time. For example, users who sign in to Windows Messenger can specify that they are "Online," "Busy," or "On The Phone." See Multiple points of presence.

Private network address
An Access Proxy's internal network address. Outbound traffic originating from within the internal network is routed to this address. See Access Proxy and Public network address.

Proxy
1. A Live Communications Server 2005, Proxy. A proxy can be configured as a Forwarding Proxy or an Application Proxy. A Forwarding Proxy simply receives and forwards messages originating from within the internal network. An Application Proxy hosts applications that filter or otherwise process messages before passing them along. A Proxy is deployed inside the network boundary but outside of any pools. It does not home users and is not connected to the user database. See Application Proxy and Forwarding Proxy.
2. In Live Communications Server architecture, the server component or module that receives and forwards SIP requests.

Public network address
An Access Proxy's external network address. Inbound traffic originating from outside the internal network is routed to this address. See Access Proxy and Private network address.

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Registration
The process by which a Session Initiation Protocol (SIP) client notifies Live Communications Server that a user has signed in and that the client is running on a particular device (such as a computer) at a particular network address (typically an IP address). See Client and Home server.

Remote user
An authorized user connecting from outside the private network. Also called an outside user.

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Session Initiation Protocol (SIP)
A signaling protocol used by Live Communications Server and clients to initiate, manage, and terminate real-time communications and multimedia sessions over an IP network. See SIP for Instant Messaging and Presence Leveraging Extensions.

Session Initiation Protocol (SIP) URI
The name by which Live Communications Server identifies a user account. SIP URIs typically take the form: sip:UserName@ DomainName. UserName is typically the name of the user account in Active Directory, and DomainName is typcially the name of the Active Directory domain of that user. See Phone URI.

SIMPLE
See SIP for Instant Messaging and Presence Leveraging Extensions (SIMPLE).

SIP
See Session Initiation Protocol (SIP).

SIP Application
A managed code application that runs in a separate process from Live Communications Server. It consists of an application manifest and at least one Server Agent object, which is the point of communication between the application and Live Communications Server. SIP applications use classes defined in the Microsoft.Rtc.Sip namespace and register with Live Communications Server through the MSFT_SIPApplicationsSetting class defined in the Live Communications Server Windows Management Instrumentation schema. See Application Manifest, Microsoft Sip Processing Language (MSPL), and WMI (Windows Management Instrumentation) classes.

SIP client
An RTC (real-time communications) client, such as Windows Messenger, that uses SIP (Session Initiation Protocol) to establish and maintain RTC sessions with a SIP server. See Client, Session Initiation Protocol (SIP), and SIP server.

SIP Domain
A domain enabled for SIP messaging; for example, a Live Communications Server domain.

SIP for Instant Messaging and Presence Leveraging Extensions (SIMPLE)
An extension to the Session Initiation Protocol (SIP) that supports sharing instant messages and presence information in an IP network.

SIP Processing Language (SPL)
See Microsoft SIP Processing Language.

SIP protocol stack
The Live Communications Server component responsible for initiating, maintaining, and terminating SIP sessions.

SIP server
A server, such as Live Communications Server 2005, that uses SIP (Session Initiation Protocol) to manage real-time communication among SIP clients, such as Windows Messenger. See Client, Session Initiation Protocol (SIP), and SIP client.

SIP/PSTN gateway
A protocol conversion application situated at the boundary between the PSTN (public switched telephone network) and an IP network enabled for SIP (Session Initiation Protocol). The gateway converts SIP signaling protocols to PSTN equivalents, and vice-versa, thereby enabling call conversion between the two networks. See Session Initiation Protocol (SIP).

Standard Edition
Live Communications Server 2005 Standard Edition. Standard Edition server consists of a single home server and includes a local MSDE 2000 (Microsoft SQL Server Desktop Engine) database for storing user information. The functional equivalent of a Live Communications 2003 Standard Edition home server.

Static Route
An IP address designating, typically, a SIP/PSTN gateway or voice mail server. A list of such addresses is maintained in a static routing table. If an entry is found in the static routing table that matches the Request-URI in the message, then the request is marked as authorized for routing, and routing is complete. If the IP address does not match an entry in the static routing table, then the request is failed at this point. See SIP/PSTN gateway.

Subscriber
A SIP client that requests presence information about a SIP user.

Subscription
The process whereby a SIP (that is, Live Communications Server) client, acting on behalf of a SIP user, requests presence information about another SIP user. See Client and Presence.

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Throttle
Restrict the number of permitted connections and the permitted transaction rate to a server or pool. Trusted servers are permitted a larger number of connections and a higher transaction rate than clients.

TLS
Transport Layer Security protocol. An industry standard designed to protect the privacy of information communicated over the internet. In TLS, a server proves its identity to a client by sending it a certificate obtained from a trusted certificate authority. In MTLS (Mutual TLS), the client also presents a certificate to the server. Live Communications Server users MTLS to help established trusted connections between servers.

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Unprep
Undo preparation of a domain, forest, or Active Directory schema. See Prep domain, Prep forest, and Prep schema.

URI
Uniform Resource Identifier. See Session Initiation Protocol (SIP) URI.

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Windows Messenger
The recommended SIP client for Live Communications Server 2005.

WMI (Windows Management Instrumentation) classes
The Microsoft extension to the Distributed Management Task Force (DMTF) Web-Based Enterprise Management (WBEM) initiative. WMI classes for Live Communications Server 2005 enable administrators to programmatically configure and manage their deployments. Most WMI class properties correspond to settings that also can be manually configured using the Live Communications Server 2005 user interface.