Nortel AS 5300 User manual

Nortel Media Application Server 6.0 for AS 5300
Fundamentals
NN44470-100

Document status: Standard
Document issue: 01.01
Document date: 03 June 2008
Product release: Release 6.0
Job function: Product Fundamentals
Type: NTP
Language type: English
Copyright © 2008 Nortel Networks. All Rights Reserved.
Sourced in Canada and the United States
Nortel, the Nortel logo and the Globemark are trademarks of Nortel Networks.

- 3 -
Contents
Nortel Media Application Server 6.0 for AS 5300
Fundamentals
NN44470-100 01.01 Standard
Release 6.0 03 June 2008
Copyright © 2008, Nortel Networks
Contents
New in this release 5
Features 5
Other changes 5
Introduction 6
MAS installation 7
Architecture and supported hardware and software 7
Session controller 8
VXML browser 8
SIP Multimedia Conductor (SIPMC) 8
Multimedia Controller 8
IVR media processor (IVRMP) 9
Conference media processor 9
Multimedia Content Store 9
Stream source 9
Reporter 9
MAS installation 9
Options for MAS application deployment 10
Application deployment options 11
Maintenance Releases 12
MAS commissioning 13
AS 5300 commissioning for MAS 13
Packaged applications 13
MAS clusters 14
SIP signaling 17
Media conferencing 19
Media settings 21
Continuous streaming 24
MAS administration and security 26
Access security setup 26
Remote Desktop Protocol 28
IPSEC configuration 29
Security tools 29
Certificate management 30
Service and configuration data backup 31
Automatic and manual backups 31
System maintenance 33

- 4 -
Contents
Nortel Media Application Server 6.0 for AS 5300
Fundamentals
NN44470-100 01.01 Standard
Release 6.0 03 June 2008
Copyright © 2008, Nortel Networks
MAS performance management 34
MAS fault management 35
Fault management architecture 35
SNMP management 36
Supported MIBs 36
Syslog 37
Event logs 37
Security Logs 38
Alarms 39
Nortel MAS Console 42
Counters & Gauges 42
Nortel MAS Console 43
Dialog boxes 45
Terminology 58

Nortel Media Application Server 6.0 for AS 5300
Fundamentals
NN44470-100 01.01 Standard
Release 6.0 03 June 2008
Copyright © 2008, Nortel Networks Nortel Confidential
New in this release
The following sections detail what is new in Media Application Server 6.0 for
AS 5300 Fundamentals (NN44470-100).
Navigation
•Features (page 5)
•Other changes (page 5)
Features
See the following sections for information about feature changes:
•MAS and AS 5300 integration (page 5)
•Administration and security (page 5)
MAS and AS 5300 integration
The Media Application Server (MAS) 6.0 supports integration with the
Application Sever (AS) 5300. For more information, see see the figure MAS
commissioning.
Administration and security
The MAS 6.0 for AS 5300 release contains new features that include SIP TLS,
Secure SRTP, and platform security. For more information, see see the figure
MAS administration and security.
Other changes
The MAS 6.0 documentation suite contains reorganized content from the
MAS 5.1, 5.0, and 4.0 documentation suites.

Nortel Media Application Server 6.0 for AS 5300
Fundamentals
NN44470-100 01.01 Standard
Release 6.0 03 June 2008
Copyright © 2008, Nortel Networks
Introduction
The Media Application Server (MAS) is a software platform for hosting
multimedia applications. This document explains MAS platform fundamentals.
Navigation
•MAS installation (page 7)
•MAS commissioning (page 13)
•MAS administration and security (page 26)
•MAS performance management (page 34)
•MAS fault management (page 35)
•Nortel MAS Console (page 42)
•Terminology (page 58)

Nortel Media Application Server 6.0 for AS 5300
Fundamentals
NN44470-100 01.01 Standard
Release 6.0 03 June 2008
Copyright © 2008, Nortel Networks
MAS installation
This chapter explains MAS installation fundamentals. For step-by-step
information about how to install the MAS platform, see Nortel Media
Application Server 6.0 for AS 5300 Installation (NN44470-300).
Navigation
•Architecture and supported hardware and software (page 7)
•MAS installation (page 9)
•Options for MAS application deployment (page 10)
•Maintenance Releases (page 12)
Architecture and supported hardware and software
This section details the system architecture for MAS 6.0 for Application Server
(AS) 5300 release as well as the supported hardware and software for that
platform. For more information, refer to Media Application Server 6.0 for AS
5300 Planning and Engineering (NN44470-200).
System architecture
The MAS platform is a software-based, media processing server. Software on
the host server performs all media processing. The MAS architecture permits
scalability for all core functions of the platform, including signaling, application
execution, content management, and media processing.
Network architecture
The MAS platform can scale from a small, duplex server solution. The system
exploits a multiprocess, multithreaded architecture that is designed to take
advantage of multiple processor core and hardware platforms. The server
achieves scalability across multiple computers by replicating the entire
system.
Supported hardware and software
The MAS platform uses commercial operating systems and commercial
hardware platforms for all processing.

- 8 -
MAS installation
Nortel Media Application Server 6.0 for AS 5300
Fundamentals
NN44470-100 01.01 Standard
Release 6.0 03 June 2008
Copyright © 2008, Nortel Networks
Supported hardware platform
You can install the MAS software on an IBM X3550. The X3550 has an Intel
XEON 5140 2.33 GHZ processor, 2 GB of RAM and a SCSI hard drive.
Supported operating system
You can install the MAS software on Windows 2003 operating system (OS). To
comply with the Defense Information Systems Agency (DISA) Security
Technical Implementation Guideline (STIG) and GR-815 compliancy, you must
install additional OS hardening patches and security software must be installed
on the MAS before you install MAS platform or MAS application software.
MAS platform core components
The MAS platform software includes the following core components:
•Session controller (page 8)
•VXML browser (page 8)
•SIP Multimedia Conductor (SIPMC) (page 8)
•Multimedia Controller (page 8)
•IVR media processor (IVRMP) (page 9)
•Conference media processor (page 9)
•Multimedia Content Store (page 9)
•Stream source (page 9)
•Reporter (page 9)
Session controller
The Session Controller (SC) provides the application execution environment
and manages all platform resources. The Media Controller provides the
conduit for communication between components and is the core of the
platform.
VXML browser
The VXML Browser (VXMLI) provides the execution environment for VXML
based applications.
SIP Multimedia Conductor (SIPMC)
The SIP Multimedia Conductor (SIPMC) provides SIP signalling and session
management capabilities.
Multimedia Controller
The Multimedia Controller (also called the SoftIVR Controller, or SC) is the
core of the MAS platform. The SC provides the conduit for communication
between components, provides the environment for application execution,

- 9 -
MAS installation
Nortel Media Application Server 6.0 for AS 5300
Fundamentals
NN44470-100 01.01 Standard
Release 6.0 03 June 2008
Copyright © 2008, Nortel Networks
and manages all platform resources. The SC is a client with respect to all other
components. The SC connects to all components identified as part of one
virtual system.
IVR media processor (IVRMP)
The IVR media processor IVRMP provides audio and video streaming, digit
collection, automatic speech recognition (ASR) and Text-to-Speech (TTS)
capabilities.
Conference media processor
The Conference media processor (ConfMP) provides audio and video
conferencing functions to the remainder of the platform.
Multimedia Content Store
The Multimedia Content Store (CStore) manages all content types and
ensures that you can access content reliably and consistently within a
platform cluster.
Stream source
The Stream source (streamsource) provides continuous pretranscoded real-
time audio to the IVRMP to facilitate a radio broadcast effect. Multiple IVRMP
channels use this feature to listen to the same real-time audio stream without
transcoding the stream on each channel or connecting each channel to a
remote server. Primarily, the SSRC is used for music-on-hold streaming or
connecting to Internet streaming radio servers.
Reporter
Reporter (reporter) generates scheduled reports (CSV, HTML) with optional
FTP/SMTP delivery. Reporter also replicates OM and call detail records.
MAS installation
The MAS platform and its associated applications are installed together on a
commercial off-the shelf (COTS) server. The server is shipped with a
hardened version of Microsoft Windows Server 2003 preinstalled. After you
power on the server, change the IP address, netmask, gateway, and host
name. A Gigabit Ethernet (GbE) (recommended) or 100 MB full-duplex
network connectivity is required. Quality of service (QoS) policies on the
switch connecting directly to the server must trust the server to allow
Differentiated Services Code Point (DSCP) markings to flow through the
switch.

- 10 -
MAS installation
Nortel Media Application Server 6.0 for AS 5300
Fundamentals
NN44470-100 01.01 Standard
Release 6.0 03 June 2008
Copyright © 2008, Nortel Networks
Uninstallation
Under normal circumstances, you need not uninstall the MAS platform unless
you want to perform a clean installation. Before you install the platform, you
must uninstall all applications and close all instances of the Nortel MAS
Console. If instances of the Nortel MAS Console are running when you
uninstall the MAS platform, you must restart the server.
Reinstallation
If you need to reinstall the MAS platform, you can use the MAS installation
DVD. The MAS installation DVD contains an automated installer. The MAS
platform is contained in a single installer; each application is bundled in a
separate installer. After you insert the DVD, locate and run the setup program.
MAS installation verification
After you install the MAS platform, you must verify that the IP address and
host name are correct.
Supported third-party software
Nortel supports McAfee VirusScan Enterprise Edition 8.5 only.
Options for MAS application deployment
The following sections provide an overview of the applications. available for
use on the MAS 6.0 platform, as well as the application deployment options
for the platform.
Meet Me Conferencing
The Meet Me Conferencing application provides reservation-less audio
conferencing on the MAS platform. You can use Meet Me Conferencing for
private conferencing at any time. Meet Me Conferencing is controlled by the
chairperson, who is assigned the role by an Application Administrator (AA).
For more information about Meet Me Conferencing, see Nortel Media
Application Server 6.0 for AS 5300 Meet Me Conferencing Fundamentals
(NN44470-103).
Ad Hoc Conferencing
Use Ad Hoc Conferencing to join together multiple simultaneous calls into a
single conference call. You can initiate a conference call from any client. To
initiate a conference, place a number of calls on hold and then select the Join
button in the Multimedia PC Client to transfer the calls to the conference
server and start the conference. The conference originator may leave the
conference without interrupting the call. The conference server terminates
the call when there is only one participant left. For more information about Ad
Hoc Conferencing, see Nortel Media Application Server 6.0 for AS 5300 Ad
Hoc Conferencing Fundamentals (NN44470-104).

- 11 -
MAS installation
Nortel Media Application Server 6.0 for AS 5300
Fundamentals
NN44470-100 01.01 Standard
Release 6.0 03 June 2008
Copyright © 2008, Nortel Networks
Music On Hold
With the Music On Hold application, a system administrator can provision the
MAS system to play music while a caller is hold. The Music on hold application
lets a caller know that the call is still connected. It is possible to implement the
Music on Hold application for the following types of hold: end-user, transfer,
and Call park. This application continuously plays for the user on hold and
does not restart the tune each time a user is put on hold. For more information
about Music on Hold, see Nortel Media Application Server 6.0 for AS 5300
Music on Hold Fundamentals (NN44470-106).
Announcements
The Announcements application plays recordings for branding, causes, and
treatments. You can use announcements to indicate the status of calls and
internal session manager conditions (treatments); which are used in all-circuit
busy situations. Announcements also provides treatment when calls fail to
complete, and provides branding (for example, Welcome to Nortel Networks).
For more information about Announcements, see Nortel Media Application
Server 6.0 for AS 5300 Announcements Fundamentals (NN44470-105).
Unified Communications
The Unified Communications application provides users with integrated
access to their voice-mail messages from a preferred client device, such as a
PC, voice over IP (VoIP) phone, wireless phone, or a traditional circuit
switched telephone. One single mailbox can be used by multiple telephony
devices and the messages deposited in this common mailbox may optionally
be mailed to a user’s e-mail client, offering another convenient access option
for voice mail message playback. Users manage their account through a
traditional Telephony User Interface (TUI) or through the web-based Personal
Agent (PA), which may be optionally configured for the user. For more
information about Unified Communications, see Nortel Media Application
Server 6.0 for AS 5300 Unified Communications Fundamentals (NN44470-
102).
Application deployment options
In Release 6.0, Media Application Servers are deployed as duplex clusters
(pairs) to ensure redundancy. In a duplex cluster, the MAS applications are
installed on both servers. The only exception to this rule is Meet Me, which can
be installed in an N+1 cluster configuration. You can deploy MAS applications
in one of three different deployment scenarios:
• Dedicated Deployment
• Co-resident Application Deployment (including Meet Me)
• Co-resident Application Deployment (excluding Meet Me)
The deployment scenario you select is determined by your capacity
requirements.

- 12 -
MAS installation
Nortel Media Application Server 6.0 for AS 5300
Fundamentals
NN44470-100 01.01 Standard
Release 6.0 03 June 2008
Copyright © 2008, Nortel Networks
Dedicated deployment
In a dedicated deployment scenario, each application is deployed on its own
MAS pair to the maximum capacity of that single application. However, for the
most efficient use of resources, a combination of dedicated deployment and
multi application deployment is required.
Co-resident deployment
In a co-resident deployment, up to five MAS applications (Meet-Me, Ad Hoc,
Music on Hold, Announcements, and Unified Communications) can be
deployed on the same MAS duplex.
If you choose a co-resident deployment, you must stay within the engineered
capacity limits for that co-resident deployment. You cannot, for example,
expand the capacity for Meet Me and balance that by reducing Unified
Communications capacity. If you require additional application capacity, you
can add an additional MAS pair and deploy a dedicated service to
accommodate the additional capacity requirements for that service. For
example, if you currently have a combination five deployment, and you require
additional Meet Me capacity, you can purchase additional Meet Me licenses
and servers and deploy a dedicated Meet Me server cluster to handle the
increased capacity.
The available co-resident deployment options are defined in the following
sections.
Co-resident Application Deployment (including Meet Me)
In a Co-resident Application Deployment (excluding Meet Me), all five MAS
applications are deployed on the same MAS pair.
Co-resident Application Deployment (excluding Meet Me)
In a Co-resident Application Deployment (including Meet Me), Ad Hoc, Music
on Hold, Announcements, and Unified Communications are deployed on one
MAS pair and a separate MAS pair is dedicated to Meet Me Conferencing.
Maintenance Releases
The MAS is updated or downgraded using executable installers (DVDs). To
update the MAS to the latest maintenance release, you must obtain the latest
maintenance release DVD and install the software. To downgrade to an earlier
maintenance release, you must run the installer on desired maintenance
release DVD. For the procedures to update and downgrade maintenance
releases, see Nortel Media Application Server 6.0 for AS 5300 Installation
(NN44470-300).

Nortel Media Application Server 6.0 for AS 5300
Fundamentals
NN44470-100 01.01 Standard
Release 6.0 03 June 2008
Copyright © 2008, Nortel Networks
MAS commissioning
This chapter describes the items that you can configure on the MAS platform.
For detailed information, see Nortel Media Application Server Commissioning
(NN44470-301).
Navigation
•AS 5300 commissioning for MAS (page 13)
•MAS clusters (page 14)
•SIP signaling (page 17)
•Media conferencing (page 19)
•Media settings (page 21)
•Continuous streaming (page 24)
AS 5300 commissioning for MAS
For more information about commissioning the Application Server (AS) 5300
system for use with MAS, see Nortel Media Application Server
Commissioning (NN44470-301) and the AS 5300 documentation suite.
Packaged applications
You can deploy packaged applications on the MAS platform. Packaged
applications are prepackaged applications that you configure on the system
using an installer.
Attention: This release does not currently support custom applications.
Packaged application installation and licensing
You can install packaged applications after you install and configure the MAS
platform. As part of the installation process, you must configure license keys
for all packaged applications that you install.

- 14 -
MAS commissioning
Nortel Media Application Server 6.0 for AS 5300
Fundamentals
NN44470-100 01.01 Standard
Release 6.0 03 June 2008
Copyright © 2008, Nortel Networks
To view installed packaged applications, use the Nortel MAS Console. The
Nortel MAS Console lists the application version and the current operational
state for that application. An example of a packaged application would be
Recorder.
Configuration data
Each packaged application has one or more configuration parameters that
you can modify to alter the behavior of the application. To view and modify
these application-specific parameters, use the Nortel MAS Console.
Operational state
Each packaged application has an operational state that you can view and
modify. To view and modify the operational state of an application, use the
Nortel MAS Console.
You can select one of the following operational states:
• Unlocked—This is the default. Normal call processing is performed for the
application.
• Locked—When the application enters a Locked state, existing sessions for
that application are terminated and the system redirects new traffic. You
typically place the application into a Locked state when performing
maintenance (for example, application upgrades) to the application.
• Pending Lock—When the application enters a Pending Locked state, the
system redirects new traffic for that application, while existing sessions are
preserved.
MAS clusters
A MAS cluster is a collection of MAS nodes that work closely together. A MAS
cluster shares the following resources:
• SNTP server for clock synchronization
• persistent content storage
• Controller Peer Ring
• redundant license servers
A cluster consists of N+1 active MAS servers where N is a maximum of 7 for
high availability and redundancy. An additional server is used as a spare to
accommodate one server failure. The spare server is active and handling
traffic, but the entire system is engineered to N servers of capacity (not N+1).
This ensures that enough remaining capacity is available to handle peak traffic
if one server fails.
The following terminology describes the different cluster types:
• Duplex—a cluster consisting of two MAS nodes

- 15 -
MAS commissioning
Nortel Media Application Server 6.0 for AS 5300
Fundamentals
NN44470-100 01.01 Standard
Release 6.0 03 June 2008
Copyright © 2008, Nortel Networks
• N-way—a cluster consisting of three or more MAS nodes
Because the cluster is based on system replication, you must configure the
same applications on all of the MAS servers in the same cluster and provision
any application data (such as subscriber information) for that cluster. The SIP
proxy must support load balancing across multiple MAS nodes in the same
cluster.
Persistent content storage
Configuration of the persistent content storage depends on
• the number of nodes in a cluster
• the applications that are provisioned for that cluster
• how those applications make use of the persistent content storage
For duplex configuration, the cluster consists of two nodes. On both nodes,
configure the Content Store Local Function key to Master, configure the
Content Store Peer Master Server key to contain the IP address of the peer
master node, and configure the Content Store Remote Server(s) key to a
blank value. To view an example of a duplex cluster, see CStore duplex cluster
configuration (page 15).
CStore duplex cluster configuration
For N-way configuration, the cluster consists of three or more nodes. On the
first two nodes, configure the Content Store Local Function key to Master,
configure the Content Store Peer Master Server key to contain the IP address
of its peer master node, and configure the Content Store Remote Server(s)
key to a blank value. Disable the CStore for all other nodes.
For all other nodes, configure Content Store Local Function to Idle and
configure the Content Store Remote Server(s) key to contain the IP address
of both CStore masters. Configure the Content Store Peer Master Server key
to blank. To view an example of an N-way cluster, see CStore N-way cluster
configuration (page 16).

- 16 -
MAS commissioning
Nortel Media Application Server 6.0 for AS 5300
Fundamentals
NN44470-100 01.01 Standard
Release 6.0 03 June 2008
Copyright © 2008, Nortel Networks
CStore N-way cluster configuration
Controller Peer Ring
Applications use the Controller Peer Ring to send and receive events to the
various MAS nodes in the cluster. Configuration of the Controller Peer Ring
depends on the number of nodes in the cluster and if the provisioned
applications use the Controller Peer Ring. To create the ring, configure each
MAS node with a primary and backup controller peer. You can then
dynamically add or remove MAS nodes to and from the Controller Peer Ring.
For duplex configuration, configure the Controller Peer Primary Server key to
the IP address of the other media server and configure the Controller Peer
Backup Server key to the IP address of the same server. To view an example
of a duplex controller ring, see Duplex controller ring (page 16).
Duplex controller ring
For an N-way configuration, for Node n, configure the Controller Peer Primary
Server key to the IP address of Node n+1 and the Controller Peer Backup
Server key to the IP address of Node n+2. To view an example of a 4-way
controller ring, see 4-Way controller ring (page 17).

- 17 -
MAS commissioning
Nortel Media Application Server 6.0 for AS 5300
Fundamentals
NN44470-100 01.01 Standard
Release 6.0 03 June 2008
Copyright © 2008, Nortel Networks
4-Way controller ring
SIP signaling
SIP configuration is broken into the following categories: General, Domains,
Accounts, Trusted Nodes, and Routes. The following sections describe these
categories in more detail.
SIP properties
You can modify the following SIP properties.
SIP domains
You must define all SIP domains on the MAS. You must configure a SIP
domain before you can configure SIP accounts and routes.
SIP properties
Property Description
Always use SIP default
outbound proxy
If enabled, the system routes SIP requests, which
do not match domain proxy configuration, through
the default outbound proxy (if configured), even if
the IP address is specified in the host portion of the
destination Universal Resource Indicator (URI).
Answer Delay (rings) Represents the number of rings before an
incoming SIP call is answered. To configure the
duration of a ring, use the Ring Interval engineering
parameter. Zero rings means that the call is
immediately answered.
Hide SIP User-Agent Header If enabled, the User-Agent header is not included
in SIP messaging.

- 18 -
MAS commissioning
Nortel Media Application Server 6.0 for AS 5300
Fundamentals
NN44470-100 01.01 Standard
Release 6.0 03 June 2008
Copyright © 2008, Nortel Networks
The platform has an internal domain called the wildcard domain, which is
represented with an asterisk and is the default domain if no matching domain
is found.
SIP accounts
SIP accounts are used for application registration in the SIP network. The
MAS registers all accounts against the registrar servers. For information about
the servers, see SIP registrar servers (page 19). You can view, add, and
delete SIP accounts.
SIP trusted nodes
MAS processes SIP traffic from trusted nodes only (for example, proxies and
gateways). Any requests from a nontrusted node are rejected. You can view,
add, and delete trusted nodes.
Attention: If you add or delete a trusted node, you must restart the platform
for the change to take effect.
SIP routes
Use SIP routes to define all proxy and registrar servers with which a MAS
node communicates. You can configure up to 32 routes for each domain.
SIP proxy servers
A SIP proxy server accepts MAS requests and queries the SIP registrar server
to obtain the recipient addressing information. The proxy server then forwards
the request directly to the recipient if the recipient is in the same domain or to
another proxy server if the recipient is in a different domain.
The MAS platform uses proxy server routes to route outbound SIP requests
to the appropriate proxy server for outbound traffic load sharing and failover.
Routes are selected based on the domain (or subdomain) lookup. If no
matching domain is configured, the default wildcard (*) route is used. For
example, if an outbound call is made to [email protected], the routes
associated with the techtrial.com domain are selected.
On the first routing attempt, the MAS platform selects active routes that are
online based on the lowest priority only. The weight is used to select routes
within the same priority level. Route selection from the next priority level is
chosen automatically only if the lower priority routes are either offline or fail to
respond.
For load sharing configurations, you can define multiple routes with the same
priority. For failover configurations, configure the primary routes with
priority = 0 and weight = 10 and configure the secondary routes with
priority = 1 and weight = 10.

- 19 -
MAS commissioning
Nortel Media Application Server 6.0 for AS 5300
Fundamentals
NN44470-100 01.01 Standard
Release 6.0 03 June 2008
Copyright © 2008, Nortel Networks
SIP registrar servers
A SIP registrar server is a database that contains the location of all user
agents within a domain. MAS registers its applications with all configured SIP
registrars. Registration is optional based on MAS configuration. Digest
authentication is supported.
Media conferencing
MAS supports multimedia conferencing for both audio and video streams. You
can use one of the following conferencing algorithms: basic and premium.
Basic conferencing algorithm
The basic conferencing algorithm mixes the two audio streams with the
highest energy and provides the mixed audio to the remaining participants.
The two participants with the highest energy audio streams receive only the
other active participant's audio so they do not hear themselves. The
participant with the highest energy with of the two highest energy speakers is
known as the primary active speaker. The other participant is the secondary
active speaker. (The system continually monitors the energy of all participants
in a conference, and using threshold algorithms, changes the conference
focus point.)
When some or all of the participants in the conference have corresponding
video streams, the video streams of the primary active speaker are replicated
and sent to those participants. The primary and secondary speakers see only
each other if they have video-enabled clients. The system attempts to provide
video participants with video when possible. If the active speaker does not
have video capabilities, participants receive a configurable replacement video,
which by default is an icon of a megaphone.
Premium conferencing algorithm
A more advanced conferencing algorithm (called premium conferencing)
mixes up to four parties simultaneously. Each channel runs a voice activity
detector (to determine speech versus background noise), an automatic gain
control algorithm, and a dynamic jitter buffer with compaction and packet loss
concealment. This algorithm is suitable for mixing large conferences.
Number of conferences and participants
MAS has no hard limitations on how many simultaneous conferences can
exist on the system, or how many participants can be in each conference. The
maximum number of participants in a single conference, without bridging
multiple conferences together, is limited only by the capacity of the scaled
system, which can vary based on hardware and the operating system.

- 20 -
MAS commissioning
Nortel Media Application Server 6.0 for AS 5300
Fundamentals
NN44470-100 01.01 Standard
Release 6.0 03 June 2008
Copyright © 2008, Nortel Networks
Mixing different codecs
The system can mix participants with potentially different codecs in the same
conference. To achieve this, the system transcodes the incoming streams into
a common format, mixes, and then provides each participant with the correctly
mixed audio. The system optimizes for multiple participants by transcoding the
resulting mixed audio based upon a grouping of conference participants. If
every participant uses identical codecs, at least three groups exist in a
conference.
The first group contains the primary speaker, the second group contains the
secondary speaker, and the third group contains the remainder of the
participants. The groups describe the different versions of the mixed audio
required in a conference. The first and second groups exist because the
primary and secondary speakers do not hear their own voice, thus they must
receive a different version of the audio than other participants. The third group
is for all other participants who require the mixed audio of both active
speakers.
The system must transcode all incoming audio streams to test for energy.
However, if the basic conference algorithm is used, the system must
transcode only the audio of each group and then replicate for each participant
as needed. This conserves system resources. If multiple codecs exist in a
single conference or if the premium conference algorithm is used, additional
groups are required. The system can, therefore, optimize conferences with
more than three participants because the additional system resources
required for each participant includes transcoding the incoming audio stream
and testing for energy. The additional participants are assigned to existing
groups as needed so they receive the same audio as other group members.
The MAS can provide additional media processing functions for conferences
on a global conference basis or for each participant. Optionally, the system
can allocate a global announcement port that provides broadcast
announcement capability to all participants. Additionally, the system can
allocate a pseudo resource for each participant that enables the system to
perform digit collection, speech recognition, and whisper-like functions for a
specific individual.