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Revision record: I-Gate 4000 EDGE General Description Dwg. Rev.

Pub. Rev.

Date Update Description

01 Oct-05 First edition and printing 02 Nov-05 Formatting corrections

A00 03 Apr-06 SW version Kalypso 5.1.1. Publication No. 05050301 Dwg. No. 480206-1000-101-95-A00

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I -Gate 4000 EDGE General Descript ion Contents

Contents 1 Introduction .............................................................................................. 1-1

1.1. New Generation Voice Switching Infrastructure.................................. 1-3 1.2. The I-Gate 4000 EDGE Media Gateway ............................................. 1-5

1.2.1. Industry-Leading Service Performance ................................ 1-5 1.2.2. Carrier-Grade Features ........................................................ 1-8 1.2.3. Ethernet and TDM Bearer Links ........................................... 1-9 1.2.4. Interoperability ...................................................................... 1-9 1.2.5. Synchronization .................................................................. 1-10

1.3. Veraz New Generation Network Solutions ........................................ 1-11 1.4. I-Gate 4000 EDGE Applications........................................................ 1-11 1.5. Examples of I-Gate 4000 EDGE Applications ................................... 1-13

1.5.1. TDM-to-VoIP Class 4/Tandem Switch Replacement -- Domestic and International Applications.............................................. 1-13

1.5.2. I-Gate 4000 EDGE in Nex-Gen Cellular Network............... 1-15 1.5.3. Static Trunking over IP or TDM Bearer .............................. 1-17 1.5.4. Business PRI Interface Applications................................... 1-21

2 Physical & Card Description ................................................................... 2-1 2.1. Introduction ......................................................................................... 2-1 2.2. Module Description.............................................................................. 2-1

2.2.1. IC4P Card -- 4-Port TDM Network Interface......................... 2-2 2.2.2. IC8P Card -- 8-Port TDM Network Interface......................... 2-3 2.2.3. ICHP Card -- 20-Port TDM Network Interface ...................... 2-4 2.2.4. BPSM Card -- Basic Processing and Switching Module ...... 2-5 2.2.5. XPSM Card -- Expanded Processing and Switching Module2-8 2.2.6. Power Supply Modules and Configurations........................ 2-11 2.2.7. EFTM -- Fan Tray Module .................................................. 2-13 2.2.8. ALARM Conn (Connector).................................................. 2-14 2.2.9. Grounding Connection........................................................ 2-14

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Contents I -Gate 4000 EDGE General Descript ion

3 Traffic Handling Features........................................................................ 3-1 3.1. Call Processing Features .................................................................... 3-2

3.1.1. Toll Quality Voice.................................................................. 3-3 3.1.2. Echo Cancellation................................................................. 3-4 3.1.3. Silence Suppression, VAD, and CNG .................................. 3-4 3.1.4. Adaptive Jitter Buffer ............................................................ 3-5 3.1.5. Packet Loss Concealment.................................................... 3-6 3.1.6. Signal Classification ............................................................. 3-7 3.1.7. Fax Quality ........................................................................... 3-8 3.1.8. Modem Support .................................................................... 3-8 3.1.9. Low System Delay................................................................ 3-9 3.1.10. DTMF Support .................................................................... 3-9

3.2. Packet Aggregation and Payload Shaping.......................................... 3-9 3.2.1. Router Load Balancing ....................................................... 3-10

3.3. CSB -- Compressed Common Channel Signaling Backhaul............. 3-11 3.4. Packet Priority Selection ................................................................... 3-12 3.5. QoS Protection Control ..................................................................... 3-12 3.6. TDM Bearer Redundancy Protections............................................... 3-12 3.7. Openness, Interoperability, and Service Quality ............................... 3-13 3.8. Announcement and Tone playing...................................................... 3-14

4 VerazView Management........................................................................... 4-1 4.1. VerazView functional modules ............................................................ 4-1 4.2. VerazView main features .................................................................... 4-1 4.3. Fault and Performance Manager......................................................... 4-3

4.3.1. Fault and Performance Manager Window ............................ 4-3 4.3.2. Event and Alarm Handling.................................................... 4-3

4.4. Configurator ........................................................................................ 4-4

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5 Technical Specifications ......................................................................... 5-1 5.1. Telephony Traffic................................................................................. 5-1 5.2. Trunk Interfaces (PSTN) ..................................................................... 5-2 5.3. Packet Network Interface (IP/TDM)..................................................... 5-2 5.4. Redundancy and Availability ............................................................... 5-3 5.5. System Synchronization...................................................................... 5-3 5.6. Power .................................................................................................. 5-4 5.7. Environmental Conditions ................................................................... 5-4 5.8. Physical Characteristics ...................................................................... 5-4

A Glossary....................................................................................................A-1

B Index..........................................................................................................B-1

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Figures Figure 1-1: Three-Layer Switch Model.................................................................. 1-4 Figure 1-2: New Generation Tandem Network Solution ..................................... 1-14 Figure 1-3: Nex-Gen Cellular Network Application ............................................. 1-16 Figure 1-4: Single Route Application .................................................................. 1-19 Figure 1-5: Point to Multipoint Configuration....................................................... 1-19 Figure 1-6: Multibearer and Multipoint Configuration.......................................... 1-20 Figure 2-1: IC4P Front Panel ................................................................................ 2-2 Figure 2-2: IC8P Front Panel ................................................................................ 2-3 Figure 2-3: ICHP Front Panel ............................................................................... 2-4 Figure 2-4: BPSM Front Panel.............................................................................. 2-5 Figure 2-5: XPSM Front Panel.............................................................................. 2-8 Figure 2-6: EACM Front Panel............................................................................ 2-11 Figure 2-7: EDCM Front Panel ........................................................................... 2-12 Figure 2-8: Fan Tray Unit - EFTM...................................................................... 2-13 Figure 2-9: Alarm Connector............................................................................... 2-14 Figure 2-10: Grounding Lug................................................................................ 2-14 Figure 3-1: Cliff Effect ........................................................................................... 3-7 Figure 3-2: Single TDM Bearer Redundancy Protection..................................... 3-12 Figure 3-3: Multiple TDM Bearer Redundancy Protection .................................. 3-13

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1 Introduction Veraz Networks, the leading new-generation network solutions vendor, provides a best-of-class telephony and multimedia switching solution that meets the challenge of converging current and future telecommunications capabilities onto a single Multi-Service Network Infrastructure.

Communication service providers face a complex set of challenges. Worldwide deregulation has increased the level of competition, forcing service providers to find new approaches to attract and retain profitable customers. While the ubiquity of the Internet has resulted in new opportunities for interactions with anyone, anywhere, the new competitive environment and the rise of the Internet has reduced the profitability potential of the traditional public voice network. At the same time, businesses and consumers are moving towards always-on digital connectivity through broadband and Web-enabled wireless devices to better take advantage of this connected world. These digitally empowered users are increasing the demand for customized communication services. Service providers require new efficiencies to serve today's Internet users and new flexibility to attract and retain tomorrow's profitable broadband users. To succeed, service providers must overcome the technical and financial hurdles of moving to increasingly efficient packet-based technologies and services while still leveraging existing circuit-switched voice networks.

Veraz Networks is fully aligned with this market and technology trend and has elected to concentrate the full weight of our experience and effort toward the development of new-generation switching solutions. Veraz Networks is committed to providing open and interoperable solutions consistent with the intent of the IETF, ITU, the International Softswitch Consortium, and other proponents of distributed architecture principles (e.g. IMS) and systems concepts. The Veraz Networks telecom products provide true best-of-class solutions meeting all of the requirements of the complete new-generation three-tiered reference model.

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Introduct ion I -Gate 4000 EDGE General Descript ion

At the media adaptation and transport level, the Veraz I-Gate 4000 series of media gateways provide toll quality transmission of voice, fax, and data traffic between the packet switching network and PSTN, and vice-versa. For the control and signaling level, the Veraz ControlSwitch and its suite of applications provide fully distributed softswitch functionality that transforms the traditional central office into a distributed Network Office. The resulting complete solution makes possible the deployment of flexible subscriber services from anywhere in the service provider's network, lowering network investment and operating costs. As a result, the service provider can quickly deliver high-value, differentiated new services for their specific markets, boosting their revenues and profits.

Veraz Networks' products provide far-reaching advantages to the service provider in the migration of the public voice networks to more efficient and flexible networks based on packet technology. While capitalizing on existing installed infrastructure investments, the service provider can solve current network challenges and prepare to capture new revenue opportunities through a new generation of differentiating services.

On the other hand, for greenfield network operators, the new-generation switching network paradigm will ensure, from the start, the most cost-effective solution that is fully aligned with industry trends.


I -Gate 4000 EDGE General Descript ion Introduct ion

1.1. New Generation Voice Switching Infrastructure The New Generation Network (NGN) voice and multimedia switching infrastructure (also called Voice over IP -- VoIP) is intended to cost-effectively deliver the full range of telephony, multimedia, and innovative value-added services, and at the same time reduce Total Cost-of-Ownership and Time-to-Market for services and increasing business opportunities. Furthermore, it improves the operator's capability to scale investment in telecom infrastructure to follow market demand and minimize risks.

Whether planning to expand an existing network or build a greenfield infrastructure, telecom operators view the three-layered switch architecture reference model as a preferential alternative to the historical hierarchical and monolithic circuit-switching infrastructure that has dominated the telephony industry for more than a century.

The three-layered switch model defines a "decomposed switch" built from interoperable components residing in a media adaptation layer (composed of media gateways and access devices), a call control and signaling layer (composed of softswitches and signaling gateways), and a service layer (composed of application and feature servers). The three-layered switch model approach, and a rich standardization within and between layers, give the telecom operator the flexibility to select the best-of-breed new-generation component(s) for each of the three architectural layers.

The new-generation switching infrastructure is becoming the preferential alternative for "cap-and-grow" expansion of existing networks (PSTN switch substitution), for implementation of new greenfield networks, and will ultimately displace the existing legacy telephony infrastructure at the end of its service life.

A critical requirement is that the new-generation switching infrastructure components and solutions must be designed to ensure Total Service Transparency for the call signals and services. This means that all the services currently offered by the PSTN network (e.g. voice, fax, modem, IN, video-conference) will be maintained and guaranteed by the VoIP infrastructure with the same quality and reliability that today's PSTN end-users are accustomed to and have come to expect.



One of the fundamental elements of the new-generation telecom scenario is the media gateway, providing the bridge between today's TDM-based legacy network and the new-generation services infrastructure. The media gateways must simultaneously execute two main tasks:

Perform inter-media network adaptation between the various circuit-switching and packet-switching network domains

Provide multiple-media switching platform for the various service and signaling payloads according to the required routing scenarios (e.g. TDM-to-TDM, TDM-to-IP).

Figure 1-1: Three-Layer Switch Model



1.2. The I-Gate 4000 EDGE Media Gateway The Veraz Networks I-Gate 4000 EDGE Carrier-Grade media gateway, is designed to meet the needs of telecom operators facing the following challenges:

Minimize CapEx and OpEx for VoIP network deployment requiring low and mid-size media gateways.

Maintenance and guarantee of Toll Quality voice performance equaling today's PSTN for highest end-user satisfaction and longer call duration.

Preservation of Total Service Transparency for voice, fax and data calls to capture all billable minutes regardless of the network impairments.

1.2.1. Industry-Leading Service Performance Telecom operators worldwide are aware that Toll Quality and Total Service Transparency are essential to maintaining and growing revenues. Increased Average Length of Call (ALOC) and Call Completion Ratio (CCR) amounts to higher carrier revenues and greater customer satisfaction. The I-Gate 4000 EDGE design is aimed to improve telecom operator's competitiveness due to the following unique characteristics:

Industry-Leading Toll Quality Voice: Toll Quality voice encoding and low-rate compression algorithms matching the quality attributes (e.g. Mean Opinion Score -- MOS) of the PSTN's wireline services.

Veraz Networks, one of the world's most experienced vendors in statistical voice compression and multiplexing equipment, has proven its ability to deliver Toll Quality voice, with its carrier-class bandwidth optimizing systems (DCME) operating in more than 700 networks worldwide. Veraz codecs are known for their spectral transparency and stability under the most severe traffic conditions.

The I-Gate 4000 series of media gateways simultaneously provide the best voice quality and the highest compression rate (also called gain or bandwidth reduction rate) in the market.



High-Performance Silence Suppression: Globally deployed Silence Suppression algorithms providing dual benefits: minimization of bandwidth needed on access and backbone network segments, and reduction in processing and throughput requirements on WAN network routers. These benefits are achieved without any degradation in voice quality.

The implementation of I-Gate 4000 EDGE's Silence Suppression utilizes Voice Activity Detection (VAD) and Comfort Noise Generation and Injection (CNG) features that ensure Toll Quality under any input signal level and/or original background noise condition.

Superior Echo Cancellation: State-of-the-art Veraz echo cancellers enabling the most pleasing conversational speech in the industry.

I-Gate 4000 EDGE's echo cancellation technology complies with ITU G.165 and G.168, and is currently delivering unrivaled field results i.e. low residual echo/ERLE (Echo Return Loss Enhancement), fast convergence time and no clipping at the ends of double-talk.

Highest Compression Ratio: I-Gate 4000 EDGE's Packet Aggregation allows the lowest possible consumption of IP-network bandwidth and processing resources, significantly lowering overall operations and life cycle costs. In particular, bandwidth consumption reduction challenges operators aiming to connect remote sites through expensive international and long-distance links or leased lines. In addition, Payload Shaping ensures smooth loading on the WAN routers.

Typical bandwidth compression performance of 12:1 for the G.729A codec (50% speech activity) and more than 14:1 for the G.723.1 codec while providing the highest voice quality performance in the market.

High Quality Fax Relay: Brand recognized fax relay algorithms providing bandwidth-efficient and very high picture quality fax transmission and full support of the T.38 standard.

Unmatched Signal Classification: Highly efficient signal detection and classification algorithms ensuring the highest levels of voice, modem, and fax call completion with the mandatory quality.



High-performance Jitter Buffer algorithm: Adaptive jitter buffer management algorithm ensuring jitter offset with the smallest buffer size to minimize end-to-end delay. The I-Gate 4000 EDGE can handle network jitter up to 300 msec.

Smart Packet Loss Concealment: Optimal substitution of lost packets in voice signals affected by loss of packets in the IP network, making the loss almost unnoticeable.

Bandwidth Efficient and Reliable Common Channel Signaling over IP Transmission: Robust SS7 and PRI signaling compression and transport mechanism (over SCTP) ensuring dual benefits: full signaling transparency despite IP-networks' packet loss impairments, and cost-effective network topology based on optimal location of the different new-generation network elements (e.g. Signaling Gateway).

Unique Smart Packet Priority Selection mechanism: Dynamically reduces the outgoing packet payload (bandwidth requirements) without any perceivable degradation of voice quality when a temporary (transient) traffic overload, bandwidth constriction, or network congestion occurs.

QoS Protection Control: Realtime detection of continuous congestion in a route to a specific IP destination and notification to the softswitch upon surpassing a packet loss threshold. This allows the softswitch to route new calls through alternative routes, facilitating restoration of the initial route.

Low System Delay: Lowest system delay, satisfying voice services realtime requirements, regardless of system configuration and traffic load.



1.2.2. Carrier-Grade Features The I-Gate 4000 EDGE is designed for nonstop carrier-grade applications providing:

Five 9's availability 1:1 redundancy for the processing: 1:1 BPSM redundancy using separate modules

1:1 XPSM redundancy using separate modules

This feature includes redundancy for TDM interface circuits, DSP resources, internal switching fabric, CPU, internal clock and Fast Ethernet interface circuits.

1:1 redundancy for the power supply cards and the power feed connections: 1:1 DC power supply redundancy for module and power feed using separate modules

1:1 AC power supply redundancy for module and power feed using separate modules

Non-traffic-affecting (hitless) software upgrade Hot-swappable and field-replaceable modules TDM Bearer Protection features, including Alternative (Redundant) TDM

Bearer, Alternative Bearer over IP and Traffic Load Sharing solutions

RTP Multiplexed packet tagging, enabling load sharing split by the external router of packets to the same destination

Ease of operation and powerful system management, reducing manpower requirements and simplifying training for operations staff

Management system providing intuitive GUI and web-based management tools for easy provisioning, monitoring, and troubleshooting

Uncompromised Stability: The I-Gate 4000 EDGE is designed to handle the full load and call completion rate as specified without loss of performance or impact on service quality.



1.2.3. Ethernet and TDM Bearer Links The I-Gate 4000 EDGE media gateway supports Fast Ethernet and E1 and T1 TDM bearer interfaces:

In addition, the TDM WAN interfaces can be implemented using the following protocols:

PPP ML-PPP Proprietary IPoTDM

1.2.4. Interoperability The I-Gate 4000 EDGE media gateway delivers an interoperability-ready solution, based on open interfaces and standards compliance, facilitating smooth integration with other vendors' network components, and seamless interconnection with other operators' networks -- e.g. MGCP, H.248 (future version), RTP/RTCP, T.38. Veraz is actively involved in standards organizations, and our media gateways maintain the highest level of compliance with published standards.

Veraz's total ownership of all the media gateway technologies, from the system platform to the DSP codes, results in additional benefits to the operator. These are:

An optimal solution for all functional and performance aspects of the media gateway. All the hardware and software components are specifically designed to maximize the media gateway's functional performance and achieve the most favorable cost structure.

Unique capability of guaranteeing interoperability with other vendors' products using special or non-standardized features (or feature variations).

Unmatched time-to-market and ability to respond, to meet the operator's customized needs.



1.2.5. Synchronization The I-Gate 4000 EDGE media gateway clock synchronization module is located in the BPSM and XPSM cards and supports one (1) primary and one (1) secondary clock sources.

The two clock sources should be standard E1 or T1 input-bit streams of any configured TDM interface.

In addition, the I-Gate 4000 EDGE includes an internal clock generator located in the BPSM and XPSM cards.

Under normal conditions the system will utilize the primary clock source. Upon failure or unavailability of primary clock source, then automatic switchover to the configured secondary clock source will take place. After normalization of the primary clock source, then automatic reversion is executed by the system.

If both clock sources, primary and secondary, are unavailable or detected as failed, then the system will utilize the internal clock source.

The I-Gate 4000 EDGE media gateway contains a redundant timing module (located in the redundant BPSM or XPSM card).

The Timing module complies with the following standards/specifications:

AT&T TR-62411 and Telcordia GR-1244 stratum 3 specifications (Jitter Wander tolerance/Transfer)

ITU-T Recommendations G.812, G.813 Type III specifications (operation modes)

Telcordia GR-2830-Core Jitter requirements ITU-T 825, ANSI T1.101 and ETS300 462-5 (1997) The free-running (internal) clock has an accuracy of 4.6 ppm (Stratum 3).



1.3. Veraz New Generation Network Solutions Consistent with its commitment to the new-generation network-switching paradigm, Veraz has developed partnerships with vendors of other new-generation network components.

The solutions offered by Veraz range from full vertical deployments including best-of-breed media gateway, softswitch, and application server gears, to horizontal solutions demanding a standards-based, open-interfaces media gateway ready to interoperate with other vendors' network components and legacy network equipment. This capability benefits the telecom operator by providing the best cost performance option for any immediate network and service requirement and for future business goals.

1.4. I-Gate 4000 EDGE Applications I-Gate 4000 EDGE is designed to fit easily into any new-generation network deployment model -- whether as a turnkey solution or horizontal solution in a multi-vendor deployment scenario -- enabling short Time-to-Market, minimal up-front investment and expenses, and controlled growth, in terms of both capacity and expanding services.

I-Gate 4000 EDGE's features make it an ideal media gateway for integration into different media adaptation and switching applications. It is eminently suitable for seamless integration into current networks starting migration towards new-generation-based infrastructure and IP-based service provision models, as well as greenfield networks.

Typical new-generation network solutions targeted by the I-Gate 4000 EDGE include:

Static Trunking (DCME over IP): For carriers currently transporting international or domestic traffic over a DCME infrastructure, or those building IP transport links, I-Gate 4000 EDGE media gateways carrying VoIP Static Trunking are a cost-effective starting point in the transition to a Voice-over-IP backbone network. As telephony traffic and signaling traffic are transferred in point-to-point mode there is no need for softswitch and signaling gateway elements.



Static Trunking over TDM Bearer: Enables the I-Gate 4000 EDGE to be used not only as a VoIP Media Gateway, but also as a DCME compression system which has the inherent capability of migrating to a VoIP bearer network. This feature can also be configured in the same chassis with a standard VoIP Media Gateway. The operator can then choose whether the bearer interface will be IP or TDM.

Softswitch controlled applications: A VoIP-based backbone network including I-Gate 4000 EDGE media gateways and softswitches (Class 4/Tandem or Class 5/Local switch replacement) allows the operator to build a carrier-grade new-generation network with a minimized cost-of-ownership (with no need to invest in legacy TDM switches). The I-Gate 4000 EDGE supports switching between any pair of end points, whether TDM-to-TDM or TDM-to-VoIP switching, controlled by a softswitch.

Combined-mode applications: The same I-Gate 4000 EDGE can simultaneously support Static Trunking mode for one group of TDM trunks and Softswitch-Controlled mode for a different group of TDM trunks.

Nex-Gen Cellular Network Applications: Cellular network operators are also planning migration scenarios towards the softswitch-based multi-tiered architecture. These migration plans differ depending on the ownership of the current infrastructure (fully owned or using leased facilities), expansion opportunities, and the operator's 3G (third generation) infrastructure development strategy.

A typical near-term new-generation network solution for cellular networks requires VoIP media gateways operating in Static Trunking or Switching mode for MSC-hub applications, tandem applications between the MSC's and PSTN switches, POI (Point of Interconnection) backhauling, and others.

Business PRI Interface Applications: Business customers using a PABX with PRI signaling interface can be directly connected to the I-Gate 4000 EDGE media gateway. This application provides reduced expenses for transmission resources and the interconnection of legacy customer equipment to a new-generation switching network.



1.5. Examples of I-Gate 4000 EDGE Applications

1.5.1. TDM-to-VoIP Class 4/Tandem Switch Replacement -- Domestic and International Applications I-Gate 4000 EDGE's features and small footprint makes it an ideal system for integration into different working environments -- incumbents' networks, as well as networks of Greenfield operators.

The economic and competitive benefits of a converged IP backbone network are compelling to operators, whether they are focused on their traditional service area or on extending their presence to additional out-of-region markets.

Today, many operators are improving their competitiveness by actively expanding their service provisioning capabilities to new markets. The main goals of such a strategy are to provide the fastest network and service rollout at the lowest cost. In addition, in some cases an existing bandwidth-rich backbone network for data services could be leveraged to offer voice services by using VoIP technology.

A new generation switching infrastructure network that includes VoIP media gateways and softswitches (Class 4/Tandem switch replacement) allows the operator to build a carrier-grade next-generation trunking network with minimal cost-of-ownership, and with no need to invest in legacy TDM switches. Furthermore, the operator of an IP-packet-based voice backbone network will immediately realize the benefits of an expected price decline in IP-based network technologies, as well as the economies of scale associated with a converged multi-service network platform.

Figure 1-2 depicts this solution, indicating various VoIP call paths (colored arrows).

In this scenario, the VoIP Class 4/Tandem network is implemented as a distributed switch using the softswitch and the I-Gate 4000 EDGE media gateways. The I-Gate 4000 EDGE media gateways are deployed at various sites and are connected to Class 4, Class 5 and/or MSC switches through standard TDM links (E1 or T1) and to distant media gateways through an IP packet-switching backbone. In the media gateway, TDM traffic is converted into VoIP packet payloads and transmitted



through the packet-switching network to a media gateway at the other end of the backbone path. At the receiving media gateway, the inverse processes take place. In addition to media adaptation, the media gateways can perform signal compression to reduce the bandwidth and routing resources of the backbone network through which the VoIP traffic runs. As an example, signal compression processes could include Silence Suppression G.729A codec, RTP Multiplexed Packet Aggregation and SS7 and/or PRI compression.

The whole process including establishment of call path and call handling is performed under control of the softswitch.

Figure 1-2: New Generation Tandem Network Solution



I-Gate 4000 EDGE interoperates seamlessly with existing PSTN networks and is completely standards-based allowing smooth and easy integration and interoperability with other vendors' media gateways operating with other protocols (e.g. H.323, SIP).

Note: Although Figure 1-2 shows I-Gate 4000 EDGE media gateways only, an actual application could include other I-Gate media gateways (e.g. I-Gate 4000 PRO) in sites with high numbers of TDM trunks (e.g. thousands of DS0s).

1.5.2. I-Gate 4000 EDGE in Nex-Gen Cellular Network Cellular network operators are also planning migration scenarios towards the softswitch-based multi-tiered architecture. These migration plans differ depending on the ownership of the current infrastructure (fully owned or using leased facilities), expansion opportunities, and the operator's 3G (third Generation) infrastructure development strategy.

A typical near-term next-generation network solution for cellular networks requires VoIP media gateway switches for MSC-hub applications, tandem applications between the MSC's and PSTN switches, POI (Point of Interconnection) backhauling, and others.

Signal compression processes could include Silence Suppression, G.729A codec, RTP Multiplexed Packet Aggregation, and SS7 and/or PRI compression.

The I-Gate 4000 EDGE media gateway also supports the GSM-EFR codec, providing a high-quality alternative for multi-hop voice compression cell paths including cellular network segments.

Figure 1-3 illustrates an example of a Nex-Gen cellular network application. The I-Gate 4000 EDGE is controlled by a softswitch and switches traffic between the MSC's (TDM-to-TDM or TDM-to-VoIP switching) or between the MSC's and the PSTN switches. The gray area shows the currently deployed legacy network components; the white area indicates the new-generation VoIP network.



Figure 1-3: Nex-Gen Cellular Network Application

Note: Although Figure 1-3 shows I-Gate 4000 EDGE media gateways only, an actual application could include other I-Gate media gateways (e.g. I-Gate 4000 PRO) in sites with high numbers of TDM trunks (e.g. thousands of DS0s).



1.5.3. Static Trunking over IP or TDM Bearer Despite trends toward plunging costs of bandwidth resources, there are still many international routes and national long-distance networks where prices are high and/or available transmission bandwidth is limited. For telecom operators carrying voice traffic over costly or bandwidth-bounded transmission links, VoIP Static Trunking systems provide a unique solution that ensures substantial savings on equipment and operations, more efficient utilization of the deployed network resources, and new opportunities for improved competitiveness and increasing profitability.

The advantages of Static Trunking are equally achievable even when no IP transmission infrastructure is available.

Typical applications that can benefit from Static Trunking include:

Transmission of long-distance international and domestic telephony services (voice, fax, modem)

Interconnection of MSC switches in mobile networks Backhaul transmission between POI's (Points of Interconnection) and MSC

applications

Call Centers/BPO As an example of Static Trunking solution, Figure 1-4 below depicts a long-distance (international or domestic) network application.



This configuration has the following characteristics:

The I-Gate media gateways are interconnected to the PSTN or MSC switches through standard E1 or T1 trunk interfaces. The TDM trunks contain 64 kbps DS0 channels carrying the uncompressed telephony signals (e.g. voice, fax, modem) and/or signaling (e.g. SS7, PRI).

At the I-Gate media gateways, the uncompressed traffic from the switches is compressed and carried over the bearer (using long-distance transmission network) to the I-Gate media gateways at the distant site where the received payloads are decompressed.

I-Gate compression algorithms allow a strong reduction in the required bandwidth resources while ensuring high voice quality performance. The compression mechanisms include low-rate encoding (e.g. G.729A, G.723.1, GSM-EFR), Silence Suppression, and RTP Packet Aggregation. In addition, Toll Quality service is ensured by a unique implementation of processing techniques that include: Echo Cancellation, Voice Activity Detection, Spectral Background Noise Injection, Packet Loss Concealment, Adaptive Jitter Buffer, and Smart Packet Priority Selection.

On the bearer (long-distance) side, the I-Gate media gateways can support IP as well as TDM interfaces.

The allocation of DS0 channels to a given destination is performed statically (semi-permanent connections provisioned by the operator), without need for softswitch or signaling gateway.

The I-Gate 4000 EDGE can interwork with the international PSTN switch via Q.50 control protocol (types A and B), which provides Dynamic Load Control (DLC) for traffic overload conditions in international links.

It should be noted that the long-distance transmission link can be implemented using an IP packet network or a TDM (PDH or SDH) network.

A Static Trunking system can be deployed according to either a single-route point-to-point configuration as shown in Figure 1-4, or in a hub point-to-multipoint configuration as shown in Figure 1-5, or in a multi-bearer and multipoint configuration as shown in Figure 1-6.



Figure 1-4: Single Route Application

Figure 1-5: Point to Multipoint Configuration



Figure 1-6: Multibearer and Multipoint Configuration

Contributing to a further OpEx reduction is the fact that one single VerazView management system can simultaneously control all the media gateways in a network and that the management information is carried in-band over the bearer links (without need for separate transmission resources).



1.5.4. Business PRI Interface Applications Business customers using a PABX with PRI interface can be directly connected to the I-Gate 4000 EDGE media gateway. In this application, the I-Gate 4000 EDGE supports the telephony traffic (e.g. voice, fax, modem) and the PRI (ISDN) signaling.

I-Gate 4000 EDGE provides termination to the PRI signaling and carries the relevant messages over IUA (SIGTRAN) to the softswitch, according to the following:

Full termination functionality for LAP-D layer in compliance with ITU-T Q.921, ETSI ETS 300 125, ANSI T1.602 and Telcordia TR-NWT-793.

Support for the ISDN variants are derived from the above standards (configurable)

IUA support enables the I-Gate 4000 EDGE to deliver connectivity to PABX's in addition to the connectivity to SS7 switches. I-Gate 4000 EDGE enables mixed ISDN and SS7 support in the same system.

This application provides reduced expenses for transmission resources and the interconnection of legacy customer equipment to a new-generation switching network.



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Physical & Card Description

2 2.1. Introduction The I-Gate 4000 EDGE Media Gateway is encased in a 1U high chassis designed to be both rugged and offer protection against electromagnetic interference (EMI). Table 2-1 provides the physical dimensions of the I-Gate 4000 EDGE terminal.

Table 2-1: I-Gate 4000 EDGE Dimensions

Dimension Terminal Width 435 mm (not including mounting brackets) Height 44.45 mm (1.00 inch, 1U) Depth 350 mm (13.8 inches)

2.2. Module Description The I-Gate 4000 EDGE has four types of modules:

TDM Network Interface cards: IC4P, IC8P and ICHP Traffic processing and Ethernet interface card: BPSM and XPSM Power supply card: EDCM and EACM Fan drawer: EFTM


Physical & Card Descript ion I -Gate 4000 EDGE General Descript ion

2.2.1. IC4P Card -- 4-Port TDM Network Interface The IC4P card provides four interfaces E1 (2.048 Mbps) or T1 (1.544 Mbps) bitstreams. The IC4P card supports the physical interface to external E1/T1 bitstreams (e.g. connected to a PSTN or MSC switch) and transmits and receives the internal bitstream signals to the operating BPSM or XPSM card located in the chassis.

This card contains four (4) RJ45 connectors providing 100/120 balanced impedance for the E1/T1 ports.

Figure 2-1: IC4P Front Panel


I -Gate 4000 EDGE General Descript ion Physical & Card Descript ion

2.2.2. IC8P Card -- 8-Port TDM Network Interface The IC8P card provides eight interfaces E1 (2.048 Mbps) or T1 (1.544 Mbps) bitstreams. The IC8P card supports the physical interface to external E1/T1 bitstreams (e.g. connected to a PSTN or MSC switch) and transmits and receives the internal bitstream signals to the operating BPSM or XPSM card located in the chassis.

An E1/T1 port can also be used in applications using a TDM bearer interface to the external backbone network.

This card contains eight (8) RJ45 connectors providing 100/120 balanced impedance for the E1/T1 ports.

Figure 2-2: IC8P Front Panel



2.2.3. ICHP Card -- 20-Port TDM Network Interface The ICHP card provides twenty interfaces E1 (2.048 Mbps) or T1 (1.544 Mbps) bitstreams. The ICHP card supports the physical interface to external E1/T1 bitstreams (e.g. connected to a PSTN or MSC switch) and transmits and receives the internal bitstream signals to the operating BPSM or XPSM card located in the chassis.

This card contains two (2) D-type connectors providing 100/120 balanced impedance for the E1/T1 ports.

Figure 2-3: ICHP Front Panel



2.2.4. BPSM Card -- Basic Processing and Switching Module

Figure 2-4: BPSM Front Panel

The BPSM card performs the following functions:

Handles up to 4 E1/T1 bitstreams connected to the IC4P, IC8P or ICHP card installed in the chassis

Handles up to 3 Fast Ethernet (100BaseT) interfaces to the external IP network Supports TDM switching fabrics Supports DS0 to DS0 cross-connection Performs signal and payload processing, packet encapsulation, continuity test,

and DTMF handling tasks.

Signal and payload processing includes:

Signal and Tone detection

Signal analysis

Voice Activity Detection (VAD), for Silence Suppression feature

Comfort Noise Generation (CNG), for Silence Suppression feature

Echo cancellation

Voice compression using low rate encoding algorithms (e.g. G.729A, G.723, GSM-EFR)



T.38 Fax and Fax Pass-through

Modem Pass-through

Packet Loss Concealment

Adaptive Jitter Buffer

DTMF handling (inband RTP/RFC 2833 and out-of-band MGCP/H.248 Package)

Compressed SS7 Backhaul (over SCTP)

Packetization (Ethernet and IP encapsulation) of the packet payloads. The processed signals are arranged into frames of a given size and added to the appropriate IP and Ethernet protocol overheads.

Packet Aggregation using RTP multiplexing

Supports the interface(s) to the IP network(s) via the Fast Ethernet (100BaseT) Interface(s)

Supports the IP protocol stacks (e.g. RTP, RTCP, UDP) and the protocol interface with the external softswitch using MGCP V1.0 or H.248/MEGACO (future release)

Supports PPP and ML-PPP protocols Supports alarms and status indications The BPSM card contains eight (8) LEDs which provide the following indications:

CRITICAL alarm

MAJOR alarm

MINOR alarm

The activation of one of these LEDs indicates that an alarm condition of corresponding severity was detected by the system.

STATUS of the System



Provides LINK STATUS for up to four (4) E1/T1 bitstreams Provides 1 (one) RS-232 CONSOLE port A RESET pushbutton is also provided in this card.

The BPSM card supports card redundancy. This optional feature is implemented using a second BPSM card in the chassis. In this configuration, one BPSM card operates in active mode and the redundant BPSM card operates in standby mode.

In the event of a failure of the active BPSM card, the redundant BPSM automatically executes switchover, ensuring full system operation. The switchover process is completed in a short period of time and the carried traffic is not affected.

The BPSM card also supports IP link redundancy. In case of IP link failure, the link leg is moved to a redundant link port.

The BPSM card also supports the following tasks:

Configuration handling Flash memory for configuration map and software version storage Built-In-Test (BIT) Software download facilities Maintenance control Communications with VerazView management system Configuration map support IP switch: Layers 2 and 3



2.2.5. XPSM Card -- Expanded Processing and Switching Module

Figure 2-5: XPSM Front Panel

The XPSM card performs the following functions:

Handles up to 20 E1/T1 bitstreams connected to the IC8P or ICHP card installed in the chassis

Handles up to 3 Fast Ethernet (100BaseT) interfaces to the external IP network Supports TDM switching fabrics Supports DS0 to DS0 cross-connection Performs signal and payload processing, packet encapsulation, continuity test,

and DTMF handling tasks.

Signal and payload processing includes:

Signal and Tone detection

Signal analysis

Voice Activity Detection (VAD) (for Silence Suppression feature)

Comfort Noise Generation (CNG) (for Silence Suppression feature)

Echo cancellation

Voice compression using low rate encoding algorithms (e.g. G.729A, G.723, GSM-EFR)



T.38 Fax and Fax Pass through

Modem Pass through

Packet Loss Concealment

Adaptive Jitter Buffer

DTMF handling (inband RTP/RFC 2833 and out-of-band MGCP/H.248 Package)

Compressed SS7 Backhaul (over SCTP)

Packetization (Ethernet and IP encapsulation) of the packet payloads. The processed signals are arranged into frames of a given size and added to the appropriate IP and Ethernet protocol overheads.

Packet Aggregation using RTP multiplexing

Supports the interface(s) to the IP network(s) via the Fast Ethernet (100BaseT) Interface(s)

Supports the IP protocol stacks (e.g. RTP, RTCP, UDP) and the protocol interface with the external softswitch using MGCP V1.0 or H.248/MEGACO (future version).

Supports PPP and ML-PPP protocols Supports alarms and status indications The XPSM card contains twenty-four (24) LEDs which provide the following indications:

CRITICAL alarm

MAJOR alarm

MINOR alarm

The activation of one of these LEDs indicates that an alarm condition of corresponding severity was detected by the system.

STATUS of the system



Provides LINK STATUS for up to 20 E1/T1 bitstreams Provides 1 (one) RS-232 CONSOLE port A RESET pushbutton is also provided in this card

The XPSM card supports card redundancy. This optional feature is implemented using a second XPSM card in the chassis. In this configuration, one XPSM card operates in active mode and the redundant XPSM card operates in standby mode.

In the event of a failure of the active XPSM card, the redundant XPSM automatically executes switchover, ensuring full system operation. The switchover process is completed in a short period of time and the carried traffic is not affected.

The XPSM card also supports IP link redundancy. In case of IP link failure, the link leg is moved to a redundant link port.

The XPSM card also supports the following tasks:

Configuration handling Flash memory for configuration map and software version storage Built-In-Test (BIT) Software download facilities Maintenance control Communications with VerazView management system Configuration map support IP switch: Layers 2 and 3



2.2.6. Power Supply Modules and Configurations The power supply cards are located at the rear of the I-Gate 4000 EDGE chassis. Two types of power supply are available:

220V AC using EACM card 48V DC using EDCM card The I-Gate 4000 EDGE supports power supply redundancy and double power feed using two separate EACM or EDCM cards.

2.2.6.1. EACM Card -- AC Power Supply Module

Figure 2-6: EACM Front Panel

The AC power supply card (EACM) has the following functions:

Provides the connection for AC voltage (110/220 VAC) AC to DC conversion (48 VDC) conversion DC to DC conversion (48 VDC to 12.5 VDC) Provides current limitation and short-circuit protection The EACM card includes a Power ON/OFF switch.

A second EACM card can be installed in the same chassis providing redundancy protection to the EACM card and the support for a separate (redundant) AC power feed connection



2.2.6.2. EDCM Card -- DC Power Supply Module

Figure 2-7: EDCM Front Panel

The DC power supply card (EDCM) has the following functions:

Provides the connection for DC voltage (-48/60 VDC) DC to DC conversion (48 VDC to 12.5 VDC) Provides current limitation and short-circuit protection A second EDCM card can be installed in the same chassis providing redundancy protection to the EDCM card and the support for a separate (redundant) DC power feed connection.



2.2.7. EFTM -- Fan Tray Module The EFTM is located on the right hand side of the front panel. The module contains four fans and also regulates their operation. In addition, a status LED is provided on the EFTM front panel.

Figure 2-8: Fan Tray Unit - EFTM



2.2.8. ALARM Conn (Connector) The ALARM Connector is located on the left hand side of the chassis' rear panel. The 9-pin, D-type, alarm connector is used to connect the I-Gate 4000 EDGE to an external alarm indication panel and to an ACO (Alarm Cut-Off) pushbutton.

Figure 2-9: Alarm Connector

The ALARM connector provides dry-contact interfaces for the following audio and visual alarm outputs:

CRITICAL (audio) CRITICAL (visual) MAJOR (audio) MAJOR (visual) MINOR (audio) MINOR (visual)

2.2.9. Grounding Connection A grounding connection is available on the left hand side of the I-Gate 4000 EDGE chassis' rear panel.

Figure 2-10: Grounding Lug


Traffic Handling Features

3 This chapter provides a description of the I-Gate 4000 EDGE traffic handling features, which include:

Unmatched voice, fax, and modem quality RTP Multiplexing based Packet Aggregation Bandwidth-efficient and Robust (Reliable) transmission of Common Channel

Signaling (SS7 and PRI)

Unique Packet Priority Selection technique Quality of Services Protection mechanism TDM Bearer Redundancy Protection TDM Bearer Load Sharing Mode


Traff ic Handl ing Features I -Gate 4000 EDGE General Descript ion

3.1. Call Processing Features New-generation network switching infrastructure must guarantee successful provisioning of all telephony services despite unavoidable network impairments and transmission over various media domains (e.g. IP) that could belong to different operators. Transporting packetized voice over an IP network in particular presents service quality challenges for carriers. In a connectionless IP network, packets are routed individually through a non-deterministic router-based network. Significant network delays, jitters, out-of-sequence packets, and packet-loss can degrade the quality of conversational speech and may adversely affect fax or modem services as well as signaling traffic performance.

The I-Gate 4000 EDGE ensures total service transparency that is based on unequaled performance of the following features:

Adaptive Jitter Buffer Packet Loss Concealment Signal Detection and Call Classification Fax T.38 and Fax Pass-through methods Modem Pass-through method Toll Quality Voice Echo Cancellation Silence Suppression, which includes Voice Activity Detection (VAD) and

Comfort Noise Generation (CNG)

Low System Delay


I -Gate 4000 EDGE General Descript ion Traff ic Handl ing Features

3.1.1. Toll Quality Voice Packet payloads from voice calls originating at a PSTN or MSC switch or from Customer Premises Equipment (CPE's, IAD's, or IP Phones) can be carried over an IP network at the original 64 kbps rate (G.711) or using low-rate encoding algorithms (e.g. G.729A, G.723.1, GSM-EFR).

Bandwidth resource bottlenecks in some network segments (despite the growing deployment of fiber facilities) and mid-term reductions in last-mile access costs for xDSL, Cable, and Wireless, combined with increased end-user bandwidth demands, provide a compelling case for the implementation of voice codecs in VoIP media gateways.

Speech codecs digitize and modify voice information streams. When used to compress voice calls, speech codecs cut bandwidth consumption by reducing the bitrate, but do so at the expense of quality and increased delay.

The codec's impact on perceived quality is determined by:

Internal encoding/decoding delay Ability to handle the different signal input levels Ability to operate efficiently when background noise and/or multiple speakers

are present

Ability to overcome transmission impairments (e.g. packet loss, jitter, and echo) Veraz's media gateways are designed to offer higher voice quality than any other comparable product on the market, whether used as a trunking media gateway (Class 4 /Tandem switch replacement) or in VoIP access applications.

Veraz, one of the world's most experienced vendors in statistical voice multiplexing equipment, has proven its ability to deliver Toll Quality compressed telephony traffic, with its carrier-class bandwidth optimizing systems (DCME) operating in more than 700 networks worldwide. Veraz's compression techniques and codecs are known for their spectral transparency and stability under the most severe traffic conditions.



3.1.2. Echo Cancellation Due to the significant delays found in some IP networks, high-performance echo cancellation is an essential element for pleasing conversational speech. Veraz echo cancellation solutions used in the I-Gate 4000 EDGE currently deliver unrivaled field results (e.g. low residual echo, fast convergence time, no clipping at the ends of double-talk voice spurt) in thousands of systems deployed worldwide.

I-Gate 4000 EDGE's echo cancellation complies with ITU G.165 and G.168.

3.1.3. Silence Suppression, VAD, and CNG Silence Suppression is an efficient solution for reducing bandwidth consumption and backbone network routing processing with almost no additional delay or signal degradation cost.

During a voice call, active signals are present for an average of 40% to 50% of the time. Between these active periods are silence gaps that are generated by the half-duplex nature of normal conversation and by pauses between words and sentences.

When properly implemented in the media gateway, Silence Suppression benefits the carrier in the following two ways:

Reducing IP payload bandwidth requirements by up to 60% on average on point-to-point calls. Despite the growth in the laid fiber optic cables, bandwidth resources are still limited in many network segments.

Reducing router CPU utilization in the periphery and core of the packet network. Voice packets are usually smaller and more numerous than data packets. Silence suppression reduces the number of packets generated during an average voice call, thus reducing network overhead and router CPU utilization.

These bandwidth and router CPU utilization reductions can result in significant cost savings to the carrier.



When applying Silence Suppression, two important issues need to be considered:

Detection of the beginning and the end of active speech (VAD -- Voice Activity Detection)

Generation and injection of background noise (Comfort Noise Quality) Both of these issues, if not properly addressed, can greatly degrade conversational speech quality. Periods of complete silence during a telephone conversation are uncomfortable for both parties, often giving the sensation that the call has been disconnected. During intervals of complete silence, injection of appropriate background noise (called Comfort Noise Generation -- CNG) at the receiving end enhances the subjective quality of the call.

The challenge is to properly detect the beginning and end of a speech interval (this ensures that the CNG is applied to the receiving end only within complete-silence intervals) and that the noise signal is injected with the same spectral characteristics as the original background noise at the transmit side. VAD must be very responsive, and it must at the same time be efficient and immune to background noise. This eliminates the clipping of speech signals or erroneous detection of false signals.

The I-Gate 4000 EDGE's VAD and CNG features fully meet the above requirements, ensuring Toll Quality under any signal level and/or original background noise condition.

3.1.4. Adaptive Jitter Buffer Packetized speech requires a jitter buffer to offset the delay variation (jitter) that typically occurs in IP networks. Jitter is caused by the varying length of queues in the routers located in the packet transmission path and by the transmission of packets of the same voice call over different routes. Jitter has a degrading effect on speech quality.

Veraz's adaptive jitter buffer management algorithm ensures jitter offset with the smallest buffer size to minimize end-to-end delay.

The I-Gate 4000 EDGE uses an adaptive jitter buffer algorithm that dynamically changes the buffer length in response to actual network (packet paths) conditions.



This dynamic manipulation of the jitter buffer minimizes the effects of jitter without resulting in significant increases in delay.

The I-Gate 4000 EDGE can offset network jitters of up to 300 msec.

3.1.5. Packet Loss Concealment Another quality aspect of the I-Gate 4000 EDGE media gateway is the implementation of a smart Packet Loss Concealment (PLC) algorithm.

Packet loss is a normal occurrence in IP networks. In IP networks, packets are lost due to path congestion conditions, overflow of the router buffers, and discarding of packets upon detection of errors or late arrival.

Figure 3-1 depicts the impact of packet loss on voice quality. For low packet loss rates, there is a gradual degradation on the quality of the voice signals. Above a packet loss threshold, quality degrades significantly (Cliff Effect) and becomes unacceptable.

For packets carrying audio or voice signals, PLC algorithms are designed to minimize the impact of the lost packets on the perceived quality of the received signal. When a loss-of-packet condition is detected on the receiving side, PLC algorithms generate signals that substitute for the missing signals. A well-designed PLC algorithm should generate substitute signals that have the same timbre and spectral profile as the lost signals.

Veraz media gateways employ a smart PLC algorithm that exploits the characteristics of the human voice and ear and generates optimal substitute signals, making the loss almost unnoticeable.

Some standard speech encoders have embedded PLC algorithms (e.g. G.723.1 and G.729A). For G.711 voice signals, Veraz media gateways utilize a smart PLC algorithm, which is based on ITU Rec.G.711 Appendix I, and includes several enhancements to the standard that guarantee the optimal substitute signals for the packets lost from any location of a voice signal stream.

Human voice signals can be characterized by parameters that change in a continuous way. Most of the time, noticeable changes take place at a low rate, compared to the PCM frame or packetization intervals. For these signals and for low packet loss rate



conditions, substitute signals can be synthesized based on the characteristics of the previous (not lost) signals.

Packet Loss Rate (Pkt/sec)

Voice Quality (MOS)

Cliff Effect

Packet Loss Rate (Pkt/sec)

Voice Quality (MOS)

Cliff Effect

Figure 3-1: Cliff Effect

When the lost signals belong to a voice stream interval characterized by quick and/or strong changes (e.g. after a silence interval) or under high packet loss rate conditions, a highly elaborate PLC algorithm is needed to guarantee that no unnatural artifacts will be created to substitute for the missing signals.

Veraz's smart PLC combines both determination of predictable lost signals based on the short- and long-term speech characteristics, and the best estimate of unpredictable signals using methods that take into account human audition characteristics.

3.1.6. Signal Classification Varying types of traffic (e.g. voice, modem, fax, signaling) undergo different processing. The ability to rapidly detect and classify a signal and determine how to best handle the traffic is crucial. Veraz media gateways use signal detection and classification algorithms that ensure that almost all voice, modem, and fax calls are followed to completion with the mandatory quality.



3.1.7. Fax Quality Fax performance remains a critical issue for telephony equipment. Fax traffic still makes up a significant percentage of telephone calls, and this is not expected to change significantly in the foreseeable future. Deployment of a network infrastructure inconsistent with today's fax handling methods would be a source of continuing operational problems and customer dissatisfaction.

Demodulation (Fax Relay) of fax calls is an essential process for guaranteeing picture integrity, whether the fax call is carried over a TDM or an IP transmission network. The typical impairments of IP networks make high-quality fax demodulation a key requirement.

Over the years, Veraz has developed unique, patented methods of detecting and demodulating fax calls, used in DCME equipment worldwide. These methods are employed in the I-Gate 4000 EDGE to successfully detect and process fax transmissions carried over IP. Veraz media gateways provide the highest fax-completion rate and picture quality in the industry, while complying with the T.38 standard.

In addition to Fax Relay mode, the I-Gate 4000 EDGE supports Fax Pass-Through mode. This allows successful interoperation with other media gateways that do not support T.38.

3.1.8. Modem Support Modem/VBD (Voice Band Data) calls must be seamlessly handled when transported over an IP network between PSTN ends.

The I-Gate 4000 EDGE dynamically allocates modem calls to be transparently transmitted over IP as G.711, 64 kbps unrestricted mode payload, without echo cancellation. An optional payload redundancy mechanism allows reliable transport of modem calls over IP networks with packet loss impairment. This optional protection mechanism supports various degrees of redundancy depths that can be configured by the operator.



3.1.9. Low System Delay The I-Gate 4000 EDGE delivers the lowest possible overall system delay, so critical to realtime voice applications. Veraz has consistently demonstrated the ability to design systems that meet the low-delay demands of realtime voice applications operating in today's most demanding global networks.

3.1.10. DTMF Support DTMF signaling is the basic component of many special or value-added services.

DTMF tones must be successfully carried over IP to the remote media gateway (or any other media device). After detection, the media gateway controller/softswitch is notified.

The I-Gate 4000 EDGE supports DTMF over RTP transfer according to RFC 2833. In addition, it supports the DTMF package via MGCP/H.248 protocol (with the media gateway controller/softswitch).

3.2. Packet Aggregation and Payload Shaping Bandwidth consumption reduction challenges operators aiming to connect remote sites through expensive international and long-distance links or leased lines.

In addition to high-quality codecs and silence suppression voice compression algorithms, the I-Gate 4000 EDGE's Packet Payload Aggregation feature provides a further reduction in required transmission bandwidth resources.

VoIP packets include a payload section carrying the encoded voice samples (e.g. G.711, G.729A) encapsulated within RTP, UDP, and IP protocol stack overheads of fixed size (12, 8, and 20 octets, respectively).

In order to improve the transmission efficiency (highest ratio of packet length to overhead length), the payload section should have a large length. The payload size is a function of the packetization interval (e.g. 10, 20, 30, or 40 msec). Large packetization intervals provide a better bandwidth compression rate but add higher end-to-end delay.



A better approach for higher transmission efficiency is payload aggregation based on the stacking of multiple voice call streams into a packet, using a shared overhead. This solution has nearly no impact on the end-to-end delay.

Packet Payload Aggregation benefits the carrier in the following two ways:

Reduction of bandwidth requirements on the WAN network with a compression of almost 12:1 for G.729A codec, or higher for G.723.1 codec

Reduction of the processing requirements (CPU loading) on the WAN routers due to a significant reduction (more than 96%) in the packets-per-second payload transmitted by the I-Gate 4000 EDGE

It must be stressed that the I-Gate 4000 EDGE RTP Multiplexing technique provides a high compression figure with no impact on voice quality.

In addition, the Payload Shaping mechanism ensures that the IP packets leaving the I-Gate 4000 EDGE media gateway are smoothly distributed over time, further reducing the load and processing requirements on the WAN resources.

3.2.1. Router Load Balancing The I-Gate 4000 EDGE also allows the routers (of the WAN IP network) to perform load-balancing in order to optimize the utilization of the WAN resources. The I-Gate 4000 EDGE tags the RTP Multiplexed packets, allowing the routers to split the packets to a given destination over two different IP paths (routes). The separation is done according to the UDP source port (same Destination IP address, different UDP SP).



3.3. CSB -- Compressed Common Channel Signaling Backhaul SS7 and ISDN PRI signaling is a fundamental component of the PSTN network and must be seamlessly handled by new generation infrastructure fulfilling two key requirements: highly reliable performance and maximal overall network cost-effectiveness.

The I-Gate 4000 EDGE Compressed Common Channel Signaling Backhaul feature is designed to benefit the operator with two main advantages:

A bandwidth-efficient solution for traffic loads including SS7 and/or PRI links between network loads

A robust (reliable) solution for the transmission of SS7 and PRI signaling over IP networks. The I-Gate 4000 EDGE Compressed CCS Backhaul feature uses Stream Control Transmission Protocol (SCTP) to carry the signaling messages over IP, providing a solution that is aligned with current industry trends and operators' requirements.

The I-Gate 4000 EDGE Compressed CCS Backhaul feature is based on the following:

Common Channel Signaling (CCS) channels (SS7 and PRI links) received on the trunk side are compressed and tunneled over IP to the far-end media gateway. At the far-end media gateway, the CCS messages are regenerated and transmitted to the PSTN switch.

I-Gate 4000 EDGE supports agnostic SS7 signaling compression (any MTP2 variant).

Transmission to the far-end media gateway is performed using the SCTP protocol. The SCTP may handle simultaneous associations with up to eight different destinations for signaling channel compression. CCS compression supports up to eight CCS channels in one to eight SCTP associations.

VerazView-xMS displays status and statistical reports for the compressed CCS links.



3.4. Packet Priority Selection The I-Gate 4000 EDGE supports a unique, smart, Packet Priority Selection (PPS) mechanism which dynamically reduces the outgoing packet payload when a temporary (transient) traffic overload, bandwidth constriction, or network congestion occurs. The Packet Priority Selection mechanism ensures smooth packet payload control without any perceivable degradation in voice quality.

The PPS mechanism allows a higher utilization of the bearer transmission resources (more traffic throughput) while maintaining the voice quality level.

3.5. QoS Protection Control The I-Gate 4000 EDGE supports a Quality of Service Protection Control mechanism designed to perform realtime detection of a continuous congestion condition in a route to a specific IP destination and notification to the softswitch upon surpassing a packet loss threshold. This allows the softswitch to route new calls through alternative routes, facilitating the restoration of the initial route.

3.6. TDM Bearer Redundancy Protections For TDM bearer applications, the I-Gate 4000 EDGE media gateway supports Alternative (Redundant) bearer protection and Multiple-bearer protection.

Figure 3-2 shows a 1:1, Alternative (Redundant) Bearer protection implementation. Under normal link conditions the traffic is carried over the Primary Bearer. Upon primary bearer failure the I-Gate 4000 EDGE media gateway automatically executes traffic switchover to the Alternative Bearer, without impacting the carried calls.

Figure 3-2: Single TDM Bearer Redundancy Protection



The I-Gate 4000 EDGE media gateway also supports Load Sharing operational mode. When using this traffic-carrying mode, the bearer traffic is distributed between both physical bearer links, the Primary and the Redundant links, respectively. Upon failure of one of the bearer links, the total traffic will be handled by the other bearer link.

Figure 3-3 shows a multiple bearer configuration including 2+1 bearer links. From a traffic capacity and quality perspective, the bearer traffic can be carried by two (2) bearer links, only. However, in order to provide bearer link protection, an additional bearer link is used. Under normal operational conditions (no link failure), the I-Gate 4000 EDGE media gateway traffic is distributed among all the physical bearer links (3 links in the figure). Upon failure of one of the bearer links, the total traffic will be handled by the other two bearer links.

Figure 3-3: Multiple TDM Bearer Redundancy Protection

3.7. Openness, Interoperability, and Service Quality Operators planning to deploy new-generation telephony network solutions are concerned with guaranteeing quality of services in a multi-operator and multi-vendor market environment.

The I-Gate 4000 EDGE is an open and standards-based media gateway designed to guarantee full interoperability in any new-generation switching infrastructure scenario. This allows operators to smoothly interconnect the I-Gate 4000 EDGE to any operating network based on existing or emerging standards without disruption of service and without the creation of "islands" of capability. This characteristic allows carriers to deploy newer technologies and to enjoy their benefits without isolating or forklift-replacing deployed systems and services.



Veraz media gateways provide interoperability at all levels with any IP telephony network element that complies with the following standards: MGCP, H.248 (future release) RTP, T.38, and SNMP.

Veraz's media gateway has been tested for interoperability with other IP telephony vendors' products such as media gateways, CPE's, and softswitches. This interoperability-ready capability benefits the operator with a short time-to-market response to enter new markets or satisfy growing business opportunities.

3.8. Announcement and Tone playing The I-Gate 4000 EDGE can play recorded audio announcements and tones towards the TDM channels, under control of the Media Gateway Controller (MGC) or softswitch.

The Announcements and Tones playing feature has the following characteristics:

I-Gate 4000 EDGE has a capacity of up to 100 unique messages (announcements/tones) of 10 seconds each (this is an average calculation, part of the announcements may have longer duration).

The announcement/tones files are stored in a non-volatile memory in the I-Gate Media Gateway. The operator may add new files or change existing files using the "Announcements and Tones" page in the VerazView-xMS management system. Announcement files can be replaced in run-time, without interrupting the voice traffic. The updated file will be used instead of the old one immediately after the download action.

Up to 100 different announcements/tones files may be downloaded to the Media Gateway.

The total duration of all announcements is 50 minutes (100X30 seconds). There is no limitation regarding the number of simultaneously playable

announcements. Announcements may be played simultaneously on all established connections/calls.

A specific announcement file may be played simultaneously to any number of TDM channels.



The audio packets of the announcement/tone files may be sent simultaneously to all TDM channels (or connections) instead of the incoming traffic. When a command to play an announcement is received from the MGC, the traffic packet stream is replaced by packets from the announcement file.

The user may store his database of announcement files anywhere in its network. From this database the user can download/replace the already downloaded announcement files. All downloaded announcements can be used immediately by a command from the MGC towards any TDM channel.


VerazView Management

4 The standard management tool for the I-Gate Media Gateways is the VerazView-Management System.

VerazView provides the network operator with enhanced Fault, Configuration, Performance, and Security management of the I-Gate 4000, I-Gate 4000 PRO and I-Gate 4000 EDGE media gateways.

4.1. VerazView functional modules The VerazView media gateway management feature consists of two functional modules:

Fault and Performance Manager: This module is in charge of gathering, formatting, and presenting status information from every media gateway. This module also includes:

Gateway access control functionality: performs network security tasks and ensures that only authorized VerazView stations are allowed access to the media gateways.

Software Version Management (SVM) functionality: controls software downloads and manages the various versions of all the network element software.

Configurator: This module is responsible for configuration and provisioning of the various services.

4.2. VerazView main features The main features of VerazView are:

A single station can manage all the media gateways in the network


VerazView Management I -Gate 4000 EDGE General Descript ion

Management protocol: SNMP & FTP Allows simultaneous operation by multiple operators Web-based management (WBM): an operator can manage a media gateway from

anywhere in the world by using a Web Browser (as a Client application) to access the GUI and functionalities of the VerazView (as a Server application).

Integrated Event Browser, showing a summary of events originating from the equipment sites, as well as events related to certain user operations with the VerazView application

Supports configuration validation at all levels Runtime configuration capability: changing configuration parameters for a

media gateway without shutting it down or rebooting

Security management: Authorization and authentication of users, audition of operator actions, access control and management, and management of multiple operators.

Access level (access rights): defines the set of procedures that a user is permitted to carry out. Multiple authorization levels may be defined (where each level can perform the stated tasks as well as the tasks of all previous levels):

History log of events/alarms, with filter and search utilities, for ease of use Comprehensive reports: display of vital information concerning system

management, traffic monitoring , and traffic statistics

Backup and Restore operations: for maps, managers, embedded software and Topology Tree.

Runtime Configuration: the ability to change the working parameters of the I-Gate 4000 EDGE without the need to reset the gateway and disrupt its traffic. In order to change a gateway's working parameters, the operator uses the VerazView Configurator. By working with a GUI similar to the one used during the static configuration process, the operator can change a gateway's working parameters one by one, and instruct the gateway to implement the new working parameters.


I -Gate 4000 EDGE General Descript ion VerazView Management

4.3. Fault and Performance Manager The Fault and Performance Manager is the main user interface of the VerazView management system for the management of media gateways. The Fault and Performance Manager is in charge of gathering, formatting, and presenting status information from every media gateway. From this window, the operator can perform all the functions required to monitor, manage and control the gateways easily and efficiently. The extent of a user's access is based on the assigned authorization level.

4.3.1. Fault and Performance Manager Window The Fault and Performance Manager window contains all the necessary tools to view and handle network element events, view reports and define new users. When the Fault and Performance Manager is accessed, the Fault and Performance Manager window contains the Network View.

The Network View displays the highest current alarm severity for any network element, regardless of whether the tree is expanded. For example, a site will show the highest severity of an alarm on any network element that is defined in that site. Expanding a branch enables viewing the specific network element from which the alarm originates. The highest alarm severity among all network elements is displayed beside the Network icon (Root icon).

The Fault and Performance Manager tree enables easy access to detailed information for the network elements displayed on the tree, and performance of pertinent operations. The workspace (also called the List View) of the Network View contains region, area, site, or network element icons depending on the branch of the Fault and Performance Manager tree that is selected. Right-clicking a region, area, site or network element displays additional information and permits access to a wide range of operations.

4.3.2. Event and Alarm Handling

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