converged networks - recursos voipfigure 2: migrating to converged networks to support the migration...
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Contact Centers Unified Communication ServicesIP Telephony
C o n v e r g e d N e t w o r k s
White Paper
March 2003
T a b l e o f C o n t e n t s
S e c t i o n 1 : Executive Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
S e c t i o n 2 : Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
S e c t i o n 3 : Converged Network Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
S e c t i o n 4 : Converged Network Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
S e c t i o n 5 : Converged Network Services . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
S e c t i o n 6 : Converged Network Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
6 . 1 IP Telephony/Multimedia Communciation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
6 . 2 Unified Communication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
6 . 3 Multimedia Contact Center . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
S e c t i o n 7 : Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
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S e c t i o n 1 : E x e c u t i v e S u m m a r y
Businesses today are faced with many evolutionary technologies. As Enterprises are evolving their IT infra-
structure to a common IP based network, also known as “converged networks,” IT professionals must
understand these evolutionary technologies and their implication to the bottom line in order to be
successful. The goal of this paper is to offer a technology overview of the converged networks. This paper
discusses the enterprise IT infrastructure evolution trend, key components and services of the converged
networks, and applications that are supported by the converged networks including IP telephony, multi-
media-contact center, and unified communications. This paper is complementary to the white paper titled
Converged Communications: Delivering Business Value Through IP Telephony in the sense that this
paper focuses on technology aspects of the converged networks while the other focuses on business value
of the converged networks.
S e c t i o n 2 : I n t r o d u c t i o n
Enterprises seem to be evolving now more than ever. Driven by the need to become more virtual and
global, we find that many enterprises are evolving their IT infrastructures in three phases1 as shown in
Figure 1. In the traditional phase, enterprises have separate infrastructures for voice and data networks,
with time division multiplexing (TDM) for voice and IP for data. This is where the majority of enterprises
are today.
In the converged networks phase, enterprises build out their IP networks to leverage a common infrastruc-
ture for both voice and data. The points of emphasis in this phase are on enhancing the IP network to make
certain it meets enterprise-class criteria, and improving its performance via QoS and reliability features to
enable real-time, mission-critical business and communication applications. Note that applications can be
in phase two, but linked to infrastructure that is still in phase one.
As enterprises become more distributed and business performance needs dictate enhanced end user
capabilities, converged communications applications will be deployed.
Communication without boundaries
1 Avaya white paper, “The Evolution to Converged Comunications .
Figure 1: Evolution to Converged Communications
When enterprises migrate from traditional to converged networks and then to converged communications, there
is increasing disaggregation and modularization of components and applications, with a corresponding
increase in flexibility and cost efficiency. As systems become more modularized, their services can be
deployed in more configurations. They become easier to integrate into heterogeneous and multivendor
environments, and can be distributed anywhere within the network. This increased level of reusability
gives enterprises more flexibility to create new, higher-value applications. This enables a dynamic service
creation environment that can be modified or customized as needed to meet the ever-changing needs of the
virtual enterprise. Avaya is taking the lead in disaggregating its software and systems into an open communication
architecture that will enable its customers to transition to converged communications.
Enterprises will evolve portions of their infrastructures from one phase to the next according to their
business needs and will often be in more than one of these phases at the same time. The majority of
enterprises today are transitioning between traditional and converged networks, with some leading-edge
enterprises starting to transition to converged communications. Due to the gradual nature of this migration, it
is essential that an enterprise deploys an architecture that is evolutionary enough to accommodate existing
infrastructures and investments, but extensible enough to provide a foundation for deployment of new applications
and services.
Increasing flexibility & cost efficiency of software applications
Incr
easi
ng
rel
iab
ility
& r
ob
ust
nes
s o
ver
IP
ConvergedCommunications
� Federated applicationsintegratingcommunications andbusiness services
� Dynamic service creationenvironment
� Rich multimodal userexperience
� End point intelligencewith user control
� Focus on software, openserver, Internettechnologies &methodologies in multi-vendor environment
FederatedServices
Distributed Software
Converged Networks� IP infrastructure for voice
& data� Scaleable reliable call
processing
� Multimedia contact center� Multimodal portals� Separated
communicationsapplications to leverageIP infrastructure
� Build out of webinfrastructure
IP QOS
Modular Systems
Traditional� Separate voice
and datanetworks
� Call center� Voice messaging� Best effort IP
BestEffort
Integrated
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This paper focuses on technologies and components enabling the second phase of the evolution —
Converged Networks. It describes key issues and benefits of the converged networks, services provided by
converged network and applications supported by the converged networks.
S e c t i o n 3 : C o n v e r g e d N e t w o r k O v e r v i e w
The initial driver for converged networks is often cost reduction. In fact, by leveraging the same infrastruc-
ture to carry voice and data traffic, enterprises can significantly reduce tariffs and can lower operational
costs by simplifying the operation, administration, and management (OA&M) requirements. Increasingly,
though, enterprises are transitioning to converged networks due to the ease with which new functionality
can be added and deployed to improve productivity for end users. There are two business models
enterprises can follow in transitioning to the converged environment: The Utility Model and The
Value-Added Model. In the Utility Model, an IT organization must:
• Satisfy the requirements of the majority of the company’s business and functional managers
• Have performance levels that are appropriate for the business requirements
• Have a cost structure that is low when compared to companies that provide a similar set of services at
analogous performance levels.
In the Value-Added Model, an IT organization must continually deploy some new functionality that helps
the company’s business and functional managers to achieve their goals. More detailed discussions on these
two models are covered in Converged Communications: Delivering Business Value Through IP
Telephony which is either available on www.avaya.com or can be obtained from your Avaya
representative or Authorized Business Partners.
Converged networks require that the IP infrastructure be enhanced with reliability and QoS features so that it
can support more business critical and real time transactions. Critical building blocks include fault
tolerant and redundant network designs with reliable network components (e.g., switches, routers,
gateways, VPN, feature servers), as well as the ability to support end-to-end IP-based differentiated
services by using congestion management, traffic policy and shaping, access control, and QoS signaling.
Figure 2: Migrating to Converged Networks
To support the migration to converged networks, Avaya has disaggregated its PBX, with embedded call
processing software and integrated communication applications, into three components (refer to Figure 2):
• IP QoS-enabled network components, including media servers, media gateways, VPNs, and LAN
switch, where some of the components support “hot standby” configurations.
• Scalable and reliable call processing software that can be distributed between headquarter and branch
offices, or among multiple sites, as necessary, to fit the needs of a virtual enterprise.
• Standalone applications — including contact center, unified communication, and IP telephony — that
support the same user capabilities over both IP based and TDM based network infrastructures, in a
heterogeneous multi-vendor environment.
This is the first step in Avaya’s evolution of its solution portfolio to a modular and open communication
architecture. Even at this first step, the benefits of modular systems can be realized. For example, the new
call processing software can be coupled with the appropriate combination of media servers and gateways
as needed by the various different sites in a virtual enterprise. In cases where it is imperative that a branch
office survives a link failure, it can be outfitted with the appropriate media server.
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In the following sections, we will discuss converged network components, converged network service
(IP QoS), and converged applications in more detail. Security issues of the converged networks are
addressed in the Security in Converged Networks white paper which is either available on
www.avaya.com or can be obtained from your Avaya representative or Authorized Business Partners.
S e c t i o n 4 ; C o n v e r g e d N e t w o r k C o m p o n e n t s
Figure 3 shows an example of converged enterprise network.
Figure 3: Converged Enterprise Network
Key components of a converged network include core data networking components such as LAN switches,
WAN routers and converged telephony/multimedia components including endpoints, gateways, and
servers. Their functions are described as follows:
IPPhone
IPPhone
Branch OfficeBranch Office
HeadquartersHeadquarters
PSTN
VPN/Firewall
VPN/FirewallWireless
Access Pointwith VPNenabledclients
IPSoftphonewith VPN
client
Media ServerMedia Gateway
Media Server
IPPhone
IPPhone
WAN
ISP
ISP
Internet
Mobile WorkersMobile Workers
Notebook with VPN remoteClient and IP Softphone
TelecommutingTelecommutingWorkersWorkers
DSL orCable
VPN
PC
PC
withVPNclient
withVPNclient
MediaGateway
ApplicationServers
LAN switch
LAN switch
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• LAN switches: A device that filters and forwards packets between LAN segments. LAN switches operate
at the data link layer (layer 2) and sometimes the network layer (layer 3) of the OSI Reference Model.
• Routers: A device that connects any number of LANs. Routers also allow remote offices to connect over
a WAN. Communicating layer 3 paths via routing protocols allows routers to select the best possible
path for traffic. Routers also provide traffic shaping and other QoS features that enhance multi-media
communication.
• VPN device: A networking device that implements encryption and other security mechanisms to permit
organizations to establish secure, end-to-end, private network connections over third-party networks,
such as the Internet or extranets. Some of these VPN appliances are capable of elementary QoS.
• Firewall device: A device designed to prevent unauthorized access to or from a private network.
Firewalls can be implemented in both hardware and software, or a combination of both.
• Wireless Access Point: A device that functions as a radio transceiver and bridge for wireless LAN clients
and also transfers data from the client radios to wired LAN.
• Endpoints and User Agents: In a general sense, an endpoint is a source and/or receiving side of media such
as audio or video. Examples of endpoints are a PC running an audio/video communication applica-
tion or an IP telephone. While this probably suggests that a person uses the endpoint, an endpoint can
be an automated device, such as a voice mailbox. The endpoint also terminates a signaling protocol,
such as SIP or H.323, and may be controllable from some application via an API.
A special type of endpoint is the conference bridge, also known as a mixer or Multipoint Conference
Unit (MCU). No user is associated with the conference bridge, but it acts like an endpoint.
• Gateways: A gateway provides the translation between two different networks. Such a gateway trans-
lates between the different bearer or media streams (for example, between a synchronous stream on a
DS0 in an ISDN and an asynchronous packetized stream in a packet network), and also between the
different signaling protocols (for example, between Q.931in an ISDN and SIP or H.323 in a packet
network). “Traditional” or “legacy” gateways are typically “single box” gateways, since they provide
all translation functions within a single physical box. The traditional gateway can be decomposed into
its functional parts: media gateway, signaling gateway, and media gateway controller.
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• Servers: Many functions would logically reside in a central place, such as in a server. One such function
is known as a registrar (SIP) or a gatekeeper (H.323). This service allows an endpoint to register its
current location (i.e., it maps between an IP address and an alias address, such as a SIP URI). Other
functions can reside in a server as well, such as a feature server that provides a set of “call processing”
features. The feature server can provide a wide variety of features, and can be invoked in varying
degrees depending on the call. A simple feature server can act as a redirection server or a SIP proxy. A
more complicated server might provide group or contact center features.
Network components are the basic building blocks of the converged network. They need to be available
and reliable. One of the concerns on migrating to a converged environment is network availability and
reliability. Most customers require the network and systems to be always available and to work correctly.
This is especially the case for any communications concerning emergency or other mission-critical
applications. A reliable converged network requires redundancy and fault-tolerance to be built in the
network components as well as overall network design including WAN connections and power
considerations. “99.999% reliability” also involves issues like fast fail-over protocols and the ability to
down load code into a device without taking it out of service; also known as, hot swappable hardware
and software.
S e c t i o n 5 : C o n v e r g e d N e t w o r k S e r v i c e s
Network Services in this section refer to the capabilities or services that the network infrastructure can
provide to the applications that are running on the networks. One of the key network services in the
converged networks is the Quality of Service (QoS). In the converged network environment, networks are
required to serve as a transport for a variety of applications, including mission critical business applica-
tions such as Enterprise Resource Planning, delay-sensitive voice traffic, bandwidth intensive video and
eCommerce applications. These business applications have different requirements on network resources.
Applications such as voice have stringent delay requirements and can tolerate only minimal packet loss,
while others cannot tolerate packet loss but do not have tight delay requirements. To meet the different
needs of the business applications and provide different level of network services, Quality of Service (QoS)
functions are required. QoS functions here refer to a combination of different complementary technologies
that come together to enable the delivery of differentiated services in the converged network environment.
Most commonly used QoS functions are:
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• Marking & Classification: Packet marking marks or colors packets according to policy and business rules.
Packet classification identifies and partitions the packets into different priority levels or classes of
service based on the value of one or more header fields, such as source address, destination address,
DS field, protocol ID, source port and destination port numbers, and other information such as
incoming interface. The output of the classifier is fed through a scheduler into the queuing system,
where different queuing strategies can be applied for congestion management purpose. Classification
typically takes place at the edge of network, either in the wiring closet or within the voice endpoints
themselves.
• Congestion Management: Congestion management involves packet scheduling and resource allocation. It
provides capability to control congestion by using queuing algorithms to sort and place the traffic onto
different queues and then determining how to serve the queues onto an output link based on certain
priority. Examples of these techniques include Priority Queuing (PQ), Weighted Fair Queuing (WFQ),
etc.
• Congestion Avoidance: Congestion avoidance techniques monitor network traffic loads in an effort to
anticipate and avoid congestion before it becomes a problem. Congestion avoidance techniques
involve a variety of packet dropping mechanisms, including Random Early Detection (RED) and
Weighted Random Early Detection (WRED).
• Policing and Shaping: Policing is to ensure traffic rate fit within a specified contract. Excess packets are
dropped or marked down to a lower priority to maintain network integrity. Traffic shaping buffers
traffic and distributes traffic peaks over time for smooth flows.
• Signaling: QoS signaling provides a way for an end station or network node to signal its neighbors to
request special handling of certain traffic. QoS signaling plays a key role in configuring successful
overall end-to-end QoS service across networks. Either in-band (packet coloring) or out-of-band
(RSVP) signaling can be used to indicate that a particular QoS service is desired for a particular traffic
classification.
• Call Admission Control: Accept or reject a traffic flow based on availability of network resources.
• Link Efficiency Mechanisms: Link efficiency can be used on a low speed link to improve the bandwidth
efficiency. Link efficiency mechanisms include: Compressed Real-Time Protocol (CRTP) and Link
Fragmentation and Interleaving (LFI).
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QoS functions needs to be engineered end-to-end. Depending on the traffic load and congestion situation,
different QoS functions can be used at different parts of an enterprise network to achieve required
end-to-end performance. The commonly used QoS functions at endpoints, LAN, and WAN are described
as follows:
• QoS at Endpoints: QoS functions such as packet marking and simple queuing need to be supported, at
least, by voice endpoints with embedded L2 switch. Endpoints with advanced QoS capability such as
RSVP signaling have additional advantages of being able to reserve the network resources for the
applications in a RSVP-aware network.
• QoS at LAN: QoS functions in the LAN are recommended if real-time audio and video will be transported
on the LAN. In a properly designed network, LANs do not experience significant link congestion since
the amount of traffic is often low relative to the amount of bandwidth available. However, temporary
congestion may occur in the LAN routers/switches when multiple large file transfers temporarily
occupy LAN router/switch queues. This temporary condition can cause either delay variation to
become noticeable or voice/video packets to be dropped. In order to ensure that high-bandwidth
traffic bursts do not adversely affect voice or mission-critical applications, QoS mechanisms such as
congestion management (queuing) and congestion avoidance can be used.
• QoS in the enterprise WAN: QoS functions in the WAN are useful in optimizing expensive resources since
bandwidth on a WAN link is typically more limited. QoS functions on WAN include classification,
congestion avoidance, congestion management, policing, shaping, and link efficiency mechanisms. All
or some combinations of these mechanisms can be used together to improve link efficiency, reduce
delay and jitter for delay-sensitive applications.
QoS administration and management is also a critical area. Centralized policy based tool and management
functions can be used to control and administer QoS functions end-to-end across the network to ensure
consistent QoS policy enforcement.
Avaya’s MultiService Network Infrastructure solutions (MSNI) and Enterprise Class IP Solutions (ECLIPS)
are QoS enabled. By implementing advanced QoS functions in the switches, gateways, and endpoints,
Avaya provides end-to-end QoS capabilities for converged networks to deliver the required performance
on various applications.
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S e c t i o n 6 : C o n v e r g e d N e t w o r k A p p l i c a t i o n s
Voice and voice-enabled applications are one of the most critical business applications in a converged
network. Migrating traditional voice and voice-enabled applications onto a converged network holds the
promise of lower costs and the opportunity for new features and functionalities. This section focuses on
applications such as IP telephony, multi-media contact center, and unified communications.
6.1 – IP Telephony/Multimedia Communication
Key considerations in migrating voice/multimedia communication onto a converged network include
network and system availability/reliability, scalability, voice quality, telephony feature sets, security,
manageability, standards compliance, protocol interoperability, and migration path/investment protection.
The following subsections will discuss issues related to these areas, specifically; voice quality, converged
telephony systems, migration, and protocol interoperability such as running IP telephony over a VPN.
Security issues related to IP Telephony applications are addressed in the Security in Converged
Networks white paper which is either available on www.avaya.com or can be obtained from your Avaya
representative or Authorized Business Partners.
Voice Quality In the Converged Network
Voice quality can be affected significantly, and adversely, by packet delay, packet jitter, packet loss, echo,
and choice of audio codecs. They are discussed in the following2:
• Delay: refers to the amount of time that a voice packet takes from the sender to reach the receiver
including the time it takes to do the processing inside them. Sources of delay in the network can be
processing delay at codec, buffer/queuing delays that occur in switches and routers, and transmission
delay. Very good sound Quality is achieved with one-way delay of 0-150 msec (millisecond) from user
to user. Depending upon requirements longer delays may be acceptable.
• Jitter: refers to the variation in delay, which can lead to the perception of “choppiness” in speech. Jitter
is caused by a variety of network factors, including congestion, varying packet sizes, packet mis-order,
or packet loss. Engineering QoS at network components such as routers, switches and gateways to
give voice priority treatment and/or using a Jitter buffer, can mitigate jitter. A jitter buffer is designed
to smooth packet flow by holding incoming packets for a specified period of time before forwarding
them to the decompression process. However, in so doing, it can also add packet delay.
2 Avaya IP Voice Quality Network Requirements,http://www1.avaya.com/enterprise/solutions/convergence/eclips/whitepapers/.html
• Echo: is the reflection of an audio signal back to its source. The reflection can be caused by acoustic
reverberation, electrical cross-talk in telephones or facilities, and impedance mismatches in analog
telephone lines and trunks. The perception of echo is commonly described as the experience hearing
your own voice come back through the earpiece as incoming sound and is technically measured by
determining the delay of the echoed signal and the strength of the reflected signal.
• Packet loss: Loss of packets in the network could happen due to heavily loaded networks i.e., packets
may be dropped due to queue or buffer overload in the intermediate nodes (routers, switches etc.,) or
completely filled jitter buffer at the endpoints causing choppy sounding of conversation.
• Network Packet Mis-Order: Packets can arrive out of order if they are sent over different routes. This can
be a result of an intentional situation, such a load balancing, or an un-intentional situation such as
re-routing due to network congestion. Packets that arrive out of order are discarded if they arrive
later than the jitter buffer can hold them. In this situation, network packet mis-order becomes
equivalent to packet loss.
• Codec Selection: The choice of the appropriate type of codec is typically made as a trade-off between the
cost of bandwidth and the quality of the voice communications. Table 1 lists the common speech
coding standards, the bandwidth they require, and the Mean Opinion Score (MOS) associated with
each type of codec. The MOS is a well-established method of determining voice quality by ITU.
According to ITU a MOS of 4.0 or higher is needed for toll-quality voice. Note that the bandwidth
listed in Table 2 does not include overhead associated with protocols such as UDP, and RTP.
Standard Coding Type Bandwidth (Kbps) MOS
G.711 PCM 64 4.3
G.729 CS-ACELP 8 4.0
G.723.1 ACELP 6.3 3.8
MP-MLQ 5.3
Table 1: Comparison of Speech Codec Standards
Delay cannot be eliminated completely from a VoIP path as it includes the inevitable processing time in the
endpoints and the transmission time. However, delay, jitter, and packet loss can be reduced and controlled
by enabling appropriate QoS functions at networks as described in Section 5 and other techniques such as
jitter buffer, echo cancellation, and packet loss compensation at endpoints to further improve voice quality
in the converged networks.
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Converged Telephony Systems
There are a few architectural variations of converged telephony systems. The most dominant architectures
are IP-enabled or pure LAN-based (Pure-IP)3.
IP-enabled PBX: Figure 4 shows an example of an IP-enabled system at central site.
Figure 4: IP-Enabled PBX at Central Location
In this architecture a variety of network interface cards, including integrated gatekeeper/gateway
port circuit boards, are added to existing PBXs, enabling them to interface with other devices on an IP
network, such as IP phones and soft phones connected to local and remote LANs. The call-processing
software is embedded in the PBX. Communication applications are either embedded within the PBX or
standalone but communicate with the PBX via proprietary protocols over TDM connections.
Remote Site
Central Site
WAN
PSTNPBX
Call ProcessingServer
Circuit Switch
Port Cards/Gateways
RouterRouter
ApplicationServer
IP SoftPhone
DigitalPhone
AnalogPhone
IPPhone
IP SoftPhone IP
PhoneAnalogPhone
DigitalPhone
Gateway(Survivable)
IP-enabled PBX
3 IP LAN Telephony: The Technology Migration Imperative,http://www1.avaya.com/enterprise/solutions/convergence/eclips/whitepapers/.html
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LAN-Based Telephony: In this architecture, illustrated in Figure 5, the call processing software is built on
standard hardware and runs a standard operating system. Applications can be either integrated or
separated from call processing software. The standalone applications communicate with call processing
via standard interfaces over IP infrastructure.
Media gateways in both architectures are used to provide inter-working with PSTN via either analog or
digital trunks and existing analog devices, such as fax machines and analog phones. The gateways can be
further decomposed into media gateway controller, media gateway and signaling gateway as specified in
the H.248/Megaco standard. This approach has some desirable attributes:
• Separation of application from hardware. Since hardware is separated from the application, it allows
the creation of very flexible systems. For example, it would be possible to add a media gateway to a
small or branch office to provide local survivable communications while maintaining the application
at a central location.
Figure 5: LAN-Based Telephony System
Remote Site
Central Site
IP WAN
PSTN
Call ProcessingServer
ApplicationServer
Router
IP SoftPhone
DigitalPhone
AnalogPhone
IPPhone
Router
IP SoftPhone IP
Phone AnalogPhone
DigitalPhone
Gateway
Gateway(Survivable)
AnalogPhone
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• Vendor independence – Implementation of product according to adopted standards allows mixing of
components to fit the unique requirements of any network. IT allows the enterprise to optimize
existing infrastructure investments.
Deployment/Migration: IP-enabled and LAN-based architectures offer different benefits and limitations. In the
IP-enabled architecture, the feature functionality, application support, and the reliability of the traditional
PBX are preserved. Customer’s existing traditional phones and port-cards can be reused. Therefore, this
approach offers enterprises maximum investment protection and the easiest path to migrate to the con-
verged environment. The LAN-based telephony approach offers several networking advantages. It allows
the use of a single cable plant that can scale with the network. This approach enables enterprises to
manage a single infrastructure as well as possibly combine the telecom and data IT departments into one.
The most common approach enterprises use today, as shown in Figure 6, is to deploy an IP-enabled PBX at
the central location to leverage the existing TDM infrastructure and a LAN-based PBX at new locations.
Figure 6: Deployment Scenarios
IP SoftPhone
Remote Site
Central Site
WAN
PSTNPBX
Call ProcessingServer
Circuit Switch
Port Cards/Gateways
Router
Router
ApplicationServer
IP SoftPhone
DigitalPhone Analog
Phone IP
Phone
IP SoftPhone IP
Phone AnalogPhone
DigitalPhone
Gateway(Survivable)
Call ProcessingServer
Router
DigitalPhone
AnalogPhone
IPPhone
Gateway
New Site
IP-enabled PBX
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The Avaya ECLIPS portfolio supports both implementations. With the recently announced additions to the
ECLIPS portfolio, Avaya greatly enhanced its converged telephony offerings. With the introduction of the
two new media servers and new gateways, the ECLIPS portfolio has become far more modular. Virtually
unlimited scalability can be achieved easily by adding more local or remote media gateways.
The modularity of ECLIPS portfolio and Avaya MultiVantage™ Software solution increases the
opportunities for 3rd parties to develop applications that can be supported by the Avaya ECLIPS portfolio.
Avaya’s ECLIPS achieves up to five 9s availability4 in a converged environment by combining different
levels of redundancy with a distributed network architecture and comprehensive telephony survivability
at remote sites.
With its Distributed Networking architecture, Avaya can install an S8700 Media Server with its dual Linux
processors running Avaya MultiVantage Software at a central site and can serve remote sites over a
converged WAN. This use of centralized call processing and networked applications delivers complete
and consistent telephony features and applications across the enterprise.
With Avaya’s MultiVantage Software based solutions, an enterprise’s investment can be preserved. When
Avaya introduced the ECLIPS portfolio in the Fall of 2001, Avaya’s DEFINITY® Servers could be IP-enabled
by adding an IP telephony gateway card so small to medium sized locations could take advantage of the
Avaya™ IP600 Internet Protocol Communication System. In the latest release, that migration can be
extended to a full IP-centric configuration, while still preserving the original PBX investment. In fact the
capacity for a single server can be extended to support up to 36,000 endpoints of which up to 12,000
can be IP.
VoIP over VPN
VPN and Firewall technologies are an integral part for providing security for Enterprises. Enterprise com-
munications via VPN offers opportunity for cost saving, flexible communications, and simplified network
administration. However, IP Telephony over VPN/Firewall presents certain technical challenges. The most
important challenges include achieving compatibility between IP Telephony and security protocols. One of
the examples is the issue of IP Telephony with Network Address Translation (NAT) since most VPNs and
Firewalls embed a Network Address Translation (NAT) function.
4 Avaya™ IP 600 and DEFINITY® IP Solutions: Reliability and Availability,http://www1.avaya.com/enterprise/solutions/convergence/eclips/whitepapers/.html
NAT has difficulties with protocols that embed IP address information within the payload of the IP packet.
SIP and H.323 devices allocate ports dynamically (for reception of media over UDP), and then pass these
addresses within the protocol. A typical NAT device will not be aware of this, and their translated packets
will have conflicting addresses in the IP header and in the payload. If the far end device replies back to the
payload’s address, the packet is undeliverable. Two generally accepted solutions to this problem are to:
• Use IPSec Tunneling to tunnel the NAT sensitive protocol through the public network so NAT is never
applied to the NAT sensitive protocol.
• Use application-aware NAT devices, such as H.323 or SIP aware NAT that parse application specific
messages to find addresses.
When an enterprise uses non-overlapping IP addresses across their multiple locations, either site-to-site or
site-to-SOHO, IPSec Tunneling can be used to tunnel the VoIP traffic through the IP WAN. However, when
an enterprise uses overlapping IP addresses across their multiple locations, IPSec Tunneling cannot be used
since NAT cannot be avoided. An H.323- or SIP-aware NAT is required here.
Avaya’s award-winning VPN solutions have embraced these alternatives and support IPSec and three
types of NATs today and will support H.323-aware NAT soon.
Avaya’s ECLIPS portfolio also includes an additional solution that allows H.323 traffic NATed without
upgrading VPN/Firewall for some IP Telephony configurations. By implementing a patent-pending auto-
detection/auto-compensation method on IP telephony servers and voice endpoints, a voice endpoint can
detect whether NAT is H.323-aware or not and make correction based on the info provided by VoIP server.
If the NAT is H.323-aware, no action is taken. If the NAT does not support H.323, action is taken by VoIP
servers and endpoints to correct the situation. This solution provides investment protection for customers
who do not want to upgrade their VPN/Firewall to add a VoIP application across their multiple enterprise
locations.
6.2 – Unified Communication
Voice mail and e-mail are two seemingly omni-present communication applications in the enterprise. In the
traditional networks, voice and email are run on separate networks: voice network and data networks. As
enterprises are evolving to converged networks, a new model for enterprise communications is taking
shape. The new model promises to bring consistency and seamless communication capabilities to the
enterprise and its customers by integrating communication infrastructure that spans the enterprise’s
existing and future communication channels. The new model is called Unified Communication.
a higher plane of communication
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a higher plane of communication
17
The basic building blocks for Unified Communication are:
• Multimedia Collaboration – for quick and easy voice, video and data interaction.
• Message Management – for simplified and integrated management of voice, fax, email and video
images.
• Contact Direction – for seamless access to integrated directories from anywhere and any device.
• Personal Assistant and Mobility Management – for setting personal rules for controlling how others find
me/hide me/reach me and for handling important messages.
Avaya’s Unified Communication offerings include traditional solutions such as voice messaging, unified
messaging, and audio and video conferencing, as well as new solutions that combine simplified voice,
video, and data collaboration. Avaya Unified Communication lets customers communicate within and
beyond their enterprise for better, faster decision-making and superior responsiveness to customers,
associates and suppliers.
Avaya Unified Communication Center (UCC) solutions that deliver seamless access via speech, Web, and
wireless to a suite of personal productivity tools including Avaya™ Contact Information Management,
Avaya™ Message Management, and Avaya™ Calling and Conference Management for the in-office and
mobile workers. Whether through a Web browser, a wireless device, or a speech command, Avaya Unified
Communication Center allows users to seamlessly access rich calling and conferencing capabilities for easy
collaborative working sessions. Avaya Unified Communication Center has quick and easy message
handling for effective message management, integrated access to directories and databases for contact and
information management, and virtual 24/7 assistance to calendars and tasks for increased personal
efficiency. The result? Facilitation of better, faster decisions for a more competitively differentiated
enterprise.
6.3 – Multimedia Contact Center
Businesses today are interacting with customers across more channels than ever before. More traditional
call centers are evolving to Multi-media Contact Centers to service interactions via email, Web, chat, and IP
telephony. Customers must be treated with consistent business rules, consistent service levels, and consis-
tent knowledge regardless of whether the channel of communication is traditional TDM-based telephone,
IP telephone or via one of the many other points of contact that customers are using on a daily basis.
a higher plane of communication
18
In the Multimedia Contact Center, interaction with customers includes phone, Web, email, and fax, and
new channels such as VoIP and wireless are emerging rapidly. Providing consistent customer experiences
across all these channels requires an integration of channel technologies around a single customer view
with common business decision-making, routing, management and interaction delivery. The Avaya™
Multi-media Contact Center provides a fully integrated multi-vendor, multi-platform, multi-channel
solution. Avaya’s solution integrates best in class skills based routing algorithms, runs on industry
standard platforms, supports a variety of interaction over both IP and non-IP infrastructures, as well as a
heterogeneous PBX switching environment. Avaya can deliver the customer to where ever your agent is,
in whatever way the customer prefers and then provides the management tools to enable the management
that tomorrow’s complex geographically dispersed Multi-media Contact center require.
S e c t i o n 7 : C o n c l u s i o n
Converged networks involve many evolutionary technologies and applications.. Even though the list may
seem long, Avaya is committed to help enterprises make a smooth transition to Converged Networks by
maximizing ROI and providing extremely high quality, manageable solutions. The Avaya ECLIPS portfolio,
MultiService Network Infrastructure (MSNI), Unified Communication Solutions, and Multi-media Contact
Center solutions provide enterprises a smooth migration path to the converged environment today. Avaya
is committed to providing enterprises with solutions that create an infrastructure that is evolutionary
enough to optimize existing investments, but extensible enough to provide a foundation for deployment
for new applications and services.
L e a r n M o r e
For additional information on our IP telephony solutions, please contact your Avaya Client Executive,
Authorized BusinessPartner, or visit us at avaya.com/learnmore/ip. For more information about Avaya
and our other award-winning solutions, visit avaya.com.
avaya.com
© 2003 Avaya Inc.All Rights Reserved. Avaya and the Avaya logo are trademarks of Avaya Inc. and may be registered in certain jurisdictions. All trademarks identified by the ®, SM or TM are registered trademarks, service marks or trademarks, respectively, of Avaya Inc. All other trademarks are the property of their respective owners.Printed in the U.S.A.03/03 • Ef-LB1893
About Avaya
Avaya enables businesses to achieve superior
results by designing, building and managing their
communications networks. More than one million
businesses worldwide, including 90 percent of
the FORTUNE 500®, rely on Avaya solutions and
services to enhance value, improve productivity
and gain competitive advantage.
Focused on enterprises large to small, Avaya is a
world leader in secure and reliable IP telephony
systems, communications software applications and
full life-cycle services. Driving the convergence of
voice and data communications with business
applications – and distinguished by comprehensive
worldwide services – Avaya helps customers
leverage existing and new networks to unlock value
and enhance business performance.
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a higher planeof communication
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