Obr.: a. SI2000/SI3000 ics integrated Call Server

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1 SI2000/SI3000 integrated Call Server

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3 Preface The deregulation and removal of monopolies in the telecommunications market and the arrival of new technologies has enabled service providers to reduce their operating costs and seek new sources of revenue. These new technologies make possible a convergent service that offers voice and data services to both types of traditionally separated voice and data service providers. However, this represents a great challenge to service providers, who must transform their networks to meet these new challenges, while at the same time protecting their previous investments. Because voice, internet, video, and VPN services were strictly separated in the past, we have witnessed the development of two parallel networks with different core technologies. Voice services were (and still are) offered on top of networks, and data services were offered on top of packet networks. But in the 1990s it became clear that voice services could be offered with packet technologies. As a result of this technological development it became clear that next generation networks would be packet based, and convergent voice and data services would be offered on the same infrastructure. An important part of the successful deployment of packet voice services is the intelligent network element with call-processing capabilities the call server. For the successful deployment of packet voice services other new network functions must be deployed to the network. Signaling gateways, media gateways, access gateways, media servers and application servers must be deployed alongside the call server to offer voice services with all the features that are familiar with from the world. The interconnection of all these network elements into a single solution is a very complex task involving the configuration of many network elements and complex protocols. This is why service providers are very careful when deploying packet voice services with distributed network elements. The demand for a simpler, but still effective solution, has dictated the development of integrated solutions for voice packet services within a single platform the integrated Call Server.

4 Integrated Call Server Introduction Today we are converging voice and data networks, but most voice services are still being offered on top of networks. Special, purpose-built network elements, the switches, are used to control voice services and to offer voice services to customers. Some of the basic functions performed by the network elements are: Call control and circuit switching Signaling Subscriber access Trunking Media server Advanced services (Centrex, prepaid, etc.) Call control and the circuit-switching function perform some of the key operations necessary for voice services, like charging, subscriber and trunk provisioning and the interconnection of incoming and outgoing channels. Signaling is used between switches to transfer call-relevant information between elements to enable successful call control and circuit switching. Subscriber access enables the connection of to the network. Trunking enables the interconnection of switches. The media-server function enables conferences, a variety of announcements and DTMF recognition. Advanced services include, e.g., Centrex or prepaid. These services were traditionally available with switches. network elements Functions Call Control and circuit switching Subsriber access network Media server links

5 All these functions are performed with dedicated hardware platforms. Because of the proprietary nature of these platforms, expansion and upgrading were very expensive and vendor specific. Service providers were not happy with these solutions and so vendors introduced some decomposition of the hardware platforms based on different functions. Some examples of this decomposition include special subscriber access elements. These network elements interconnected with switches using standard protocols. But the decomposition of switches was very limited and hardware elements were mostly still purpose built. Decomposed NGN architecture With new technologies, like improved processing capabilities, a common packet-based infrastructure, cheap and fast interconnections through 100Mb and 1Gb Ethernet and the basic standardization of different protocols, it became possible to decompose voice services, enabling functions to different, widely used products. Because of the huge number of installed networks, the packet voice and voice services will have to co-exist for quite some time. Interconnecting packet voice services with installed voice services is essential for the acceptance of packet voice services. This introduced some new and known basic functions that are needed for the successful deployment of packet voice services. Because and packet networks are very different in their core operation, different gateway functions must be deployed in the network: Signaling gateway Media gateway Access gateway The signaling-gateway function transforms signaling from the switch to the call server, and back. The media-gateway function performs the transformation from time slots to RTP packets, and the different protocols (G.711, G.729, G.723.1, T.38, etc.) used in packet networks. The access-gateway function enables the interconnection of terminals to a packet network. There is no need for an access function in Vo terminals because the packet core NGN network enables the interconnection of Vo terminals directly to the call server. Decomposed NGN arhitecture Functions Call Control VXML, ParlayX TTS, ASR Media gateway network network Signaling gateway MSAN Vo terminals switching Subsriber access (POTS, ISDN) Media server Advanced services

6 The call-control function is stand-alone in the NGN architecture and is performed by the call server. The decomposition of the call-control and switching functions is the main characteristic of NGN networks, and it makes possible a truly decomposed network architecture. The convergence of voice and data services resulted in the development of different protocols and functions. Some examples of convergence are VXML and ParlayX. These functions are deployed to the network on offthe-shelf servers, as required. Integrated NGN solutions In the late 1990s the concept of network development was a revolutionary one. The theory for NGN network development was build new and discard old. But it soon became clear that such a revolutionary approach was too optimistic and the introduction of NGNs would be more conservative. The technology was not mature enough to meet expectations. The interconnection of various NGN elements is very complex and the standardization of interconnecting protocols is not mature enough to allow the interconnection of elements from different vendors. And because the NGN technology is still very young, providers are very cautious when installing NGN equipment. Vendors responded to these demands with an evolutionary concept of network transformation toward a pure NGN. The key component of this evolutionary approach is the integrated call server. Vendors developed NGN network elements, but then realized that the market is just not ready for the large-scale deployment of NGN solutions, especially for CLASS 5 applications, because these applications are very complex in terms of the interconnection of different NGN network elements. So vendors started to offer integrated solutions in which they integrated different NGN functions into a single product. SCP Integrated Solution Functions Call Control VXML, ParlayX TTS, ASR Media gateway network network Signaling gateway MSAN Packet terminals switching Subsriber access (POTS, ISDN) Media server Advanced services Different vendors have chosen different strategies for integrating NGN functions. Some vendors have chosen to integrate some functions; others have chosen to integrate all functions. An example of partial integration is the integration of the media-gateway and signaling-gateway functions. An example of full NGN integration is the integrated call server, where all the functions are integrated into a single product. The interconnection of call control and other functions is done internally within the product, which is preconfigured to minimize the possibility of errors.

7 The is an integrated NGN solution that is part of the SI2000 and SI3000 product line. Iskratel has developed its own NGN deconstructed solution with all the necessary network elements to offer the full advantages of a NGN to service providers. When it become clear, especially in CLASS 5 applications, that the deployment standardization and interconnection of network elements from different vendors was just not happening, the integrated solution was developed. Different network functions developed by Iskratel for NGNs are integrated in a compact solution. This integrated solution is a mix of hardware and software integration. The heart of the integrated solution is the call-server software. This software was developed for a standard computing platform and operating system for the NGN environment. The call-server software is highly flexible and can be ported to different platforms and operating systems. This enabled Iskratel to integrate call-server software on different hardware platforms that were targeted toward a mainly narrowband solution or mixed narrow- and broadband solutions. Vo DSPs Software integration Hardware integration Integrated functions

8 Integrated solution The solution is an ideal solution for the evolution of to NGN networks. Its broad selection of and packet-signaling interfaces enables the interconnection of the in a mixed environment of and packet networks. With interfaces the enables service providers to protect their investment in technology. Access interfaces make it possible to interconnect different access-network elements with standard protocols, like V5.2, to offer an analog and an ISDN subscriber service. With trunking we can connect the to existing networks on all levels of the network with a variety of signaling, like SS7 or CAS, in different national variants. The switching functionality enables the deployment of the in a pure environment and it is future-ready for a pure NGN environment when needed. With interfaces the enables service providers to optimize their networks with a common packet transport layer and thus reduce OPEX. Trunking capabilities over packet networks make it possible to interconnect the with other call servers and media gateways using standard S-T, H.323 and S NNI protocols. On the access plane the can control packet terminals with standard S and H.323 protocol. The access plane of the enables triple-play solutions and Centrex. For additional revenue for service providers, advanced services can be created on servers with standard VXML and ParlayX interfaces to interconnect to the. Integrated Solution Addvanced services (VXML, ParlayX, TTS, ASR) switch (SS7, CAS) Call Server (S-T) PBX (PRA, CAS) MGW (H.323) Access (POTS, ISDN BRA) Access (analog) Vo terminals (H.323, S)

9 Major applications switching The various signaling and switching capabilities of the enable the interconnection of existing equipment to an NGN core network. All major signalings and their national variants are supported within the. These signalings include SS7, CAS, DSS1, Q.SIG and V5.2. Supported signaling protocols enable the interconnection of public switches, PBXs and access-network elements in today s networks with standard protocols. With switching capabilities the can be connected to the network with trunks and have alternative trunks configured for back up. This functionality enables the reliable and undisturbed operation of voice services even in the event of problems on the packet network. With switching functionality, service providers are able to fully protect their previous investments in a network. transit switch trunks trunks (alternative) local switch PBX Access node Universal access With its wide range of network interfaces, service providers can deploy subscriber service for all types of, from to packet. All CLASS 5 services are supported. Conference call, forwarding, call transfer, caller ID and many other services are integrated into the and can be offered to all for additional revenue. This gives service providers the ability to deploy a packet subscriber service in the same manner as they deploy a subscriber service. The service offering for packet is equivalent to the service offering for. Analog, ISDN and PBXs can be connected on the interfaces of the. Packet subscriber, PBX and analog (access gateway) can be connected on the interface of the. PBX PBX ISDN POTS Vo

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11 trunking The most widely used Vo application today is trunking. It was first used by alternative service providers to offer cheap international calling. Because of the fierce competition in telecommunications markets, service providers are trying to cut down OPEX. A common packet infrastructure enables a much cheaper operation for service providers and greatly improves the capacity of the network. Many traditional data and internet service providers today have a high-quality, large-capacity packet backbone and are starting to deploy the packet voice service via trunking solutions. This is a cheap alternative to traditional voice service providers and they are forced to deploy cheaper packet-backbone transport. With the service providers can build a common packet core network and interconnect with an existing network. trunking can be deployed with the using the H.323 or S-T / S NNI protocols. The S-T protocol is becoming the defacto standard for softswitch interconnection. Because the S-T protocol incorporates the transfer of SS7 signaling, the trunking is becoming equivalent to trunking in terms of functionality, but with clear advantages, like a higher capacity and lower OPEX. Different types of codecs (G.711, G.723.1, G.729, T.38, clear channel) and packetization periods are supported for an optimal traffic configuration. Integrated callserver software also enables switching between different trunks, thus enabling solutions beyond simple point-to-point trunking to multi-point trunking. SS7 Point-to-point SS7 S-T / S NNI H.323 SS7 Multi-point CAS DSS1 S-T / S NNI H.323 SS7 Lawful interception The possibility for lawful interception (LI) is mandatory in today s telecommunications equipment. The interfaces to equipment for LI functionality are well defined. With the deployment of a packet core network and trunking the LI must be provided over the packet network when necessary. The equipment for LI that controls functionality, also called the monitoring center, is today still mostly based. The equipment must guarantee the correct transfer of LI information over the packet network and change this information to a format for the monitoring center. The LI interface has three information streams, one for the administration of monitoring subjects, one for the transfer of call data (duration, number dialed, etc.) and one for the transfer of voice. All three components must be successfully transferred over the packet network. The solution for LI over a packet network, within the, implements all the requirements for a reliable LI solution. In some countries the regulations for LI request that service providers must guarantee an E1 link (31 channels) for LI purposes. This is very expensive, especially for small systems. With the

12 solution for LI over a packet network this is not necessary. The service provider can configure the with a small number of special trunks for LI. On these special trunks the transfer of data only occurs when there is some activity to be monitored. The solution is very economical in terms of traffic flow. For the purpose of LI over a packet network, a special VLAN interface is configured within the to strictly separate the LI information and other traffic. This separation ensures the integrity of the LI information, which is the main requirement for LI solutions. The aggregation of LI information for different network elements is possible with the. Within the solution the LI functionality can be applied to all types of and packet. analog LIo (SORMo) LIo (SORMo) E1 links Monitoring center Vo ISDN subscriber analog Centrex Telecommunications services are historically divided into the public and enterprise domains. Service providers typically offered a service for the public domain (mainly residential customers). The enterprise telecommunications service stayed in the enterprise domain and was usually solved with PBX switches. These switches were similar to the switches in the public domain, with some additional enterprisespecific services (abbreviated dialing, call pick-up, etc.). With the progress of technology more and more services were integrated into the public switches, and public service providers began to deploy Centrex solutions. With a Centrex solution the telecommunications services for enterprises were managed and deployed by service providers within their own public switches. Enterprise were connected directly to public switches. This eliminated the need for PBX systems and huge investments by enterprises. Enterprises received a Centrex service for a monthly fee; this service was managed by the service provider, which eliminated the need for highly trained technical personnel, thus reducing expenses. And a Centrex service could be easily spread to a large area to cover remote enterprise locations, even if these locations were not controlled by one switch, because Centrex information can be easily transferred within SS7 signaling. With the deployment of packet technologies it became possible to offer a Centrex solution to packet voice. This eliminated the need for connectivity for enterprises as the voice service could be offered directly via the packet data links. With packet connectivity directly from enterprises to service providers, a Centrex solution become even more powerful and attractive as a managed service by service providers. All the variants of a Centrex solution can be deployed with the. All types of can be integrated into the Centrex. And Centrex can be spread throughout the service provider s domain over the and the packet core network. A Centrex solution within the can be offered over a packet core network because of integrated call-server software with S-T protocol support. The S-T protocol transfers SS7 signaling, and the Centrex solution can be controlled via S-T.

13 Centrex analog Centrex Vo SS7 (centrex info) S-T (centrex info) Centrex analog Advanced services Centrex ISDN Centrex analog Centrex Vo Although the main reason for the deployment of NGN solutions today is the optimization of operation via a common packet backbone, the true power of an NGN lies in the ability to create advanced, new services very rapidly with standard interfaces. Service providers today are facing the price erosion of standard services (basic telephony, etc.) and are being forced to seek new sources of revenue. The most advanced NGN protocols integrated into the enable the creation of new services based on the latest technologies, even from third-party vendors if needed. The web-services interface is the latest technology for service creation and is integrated into the via a ParlayX interface. Another popular interface for advanced voice services today is VXML. With a VXML interpreter integrated into the, any standard VXML file can be interpreted in the. A combination with other servers, like TTS or ASR, is possible. This makes it possible to realize many advanced services. Voice portal, prepaid, personal assistant, web management and provisioning of services, IVR and many other services can be deployed with the for service providers and enterprises. Advanced services servers (VXML, ParlayX, TTS, ASR,...)

14 Some deployment scenarios Local switch Iskratel has a long history as a manufacturer of cost-effective, small, local switch solutions. This tradition is continued with the solution, as it brings true NGN technology to local switch solutions. Although the latest trends in telecommunications favor plain subscriber accesses at the local level of networks, there is still a big demand for local switch solutions in some countries where the telecommunications infrastructure is still not fully developed. The reasons for the deployment of local switch solutions are: An unreliable and small-capacity uplink network connection Access to emergency services in the case of network uplink problems A lot of local traffic because of flat-rate local tariffs Traffic optimization For these reasons, access solutions are very hard to deploy as they need a much bigger network uplink capacity and reliability. That is why local switch solutions are deployed to increase the penetration of the telecommunications infrastructure and increase the potential for country development. The is ideal for a local switch solution as it is reliable and cost effective. It incorporates the latest NGN technology and can utilize the small-capacity network uplink with bandwidth-optimized trunking. With this technology the uplink can be transformed to an uplink (with technology for the transfer of traffic over an E1 link, for example) to increase voice-channel uplink capacity. To satisfy the regulation, the LIo (SORMo) technology can be used to successfully deploy a fully regulative, compliant local switch solution. Because the incorporates the latest NGN technology, it is very straightforward to upgrade the solution toward a deconstructed NGN solution when the small-capacity network uplinks will be replaced with largecapacity, reliable uplinks (the deployment of optical, for example). E1 links SS7 * overe1 S-T, LIo (SORMo) Monitoring center * ISDN analog The pure solution is fully NGN ready, when adequate packet uplink will be set up

15 Enterprise solutions The enterprise market for telecommunications equipment is rapidly changing with the advances in technology. The voice-over-packet technology is giving enterprises the possibility to deploy a common packet infrastructure for converged services and reduce OPEX. Even though new technologies are developing very quickly, there is still a lot of installed equipment, and enterprises want to protect their previous investment. And new NGN protocols enable the development of new, converged services to improve enterprise productivity and reduce expenses, thus improving the profitability of enterprises. All these expectations can be met with the. The is very flexible and cost effective for enterprise solutions because of its broad range of and packet interfaces. And the possibility to deploy advanced services through NGN standard protocols gives it the ability to deploy an advanced NGN enterprise solution. The rich selection of interfaces enables enterprises to protect their previous investment (analog phones, wiring, etc.) and to connect to a service-provider network, as many service providers today offer only uplinks. The packet interfaces make it possible to deploy a converged infrastructure for the transport of voice and data traffic. This is ideal for new locations where only a packet core network can be built, or for the expansion of existing locations with a converged infrastructure. The can be deployed as a true PBX system and can be connected to a service provider, directly through a packet uplink. The NGN protocols integrated in the enable the creation of new services based on the latest technologies (Web services, VXML, etc.), even from third-party vendors, if required. The brings the power of NGN technology to the enterprise. And the compact form of the simplifies the deployment and maintenance of the solution. Addvanced services (VXML, ParlayX, TTS, ASR) uplink Existing infrastructure Analog terminals Enterprise solution Packet uplink in case of operation of Si2000SI2000 as PBX Packet link for connection of remote locations New packet infrastructure ISDN terminals Analog terminals Analog terminals Vo terminals

16 Triple-play solutions (VoDSL) Triple play is the combination of voice, data, and video services offered as a bundled service for a price that is less than the price of the individual services. Regarding the technology, triple play represents the ability to offer voice, video and data services from the same service provider. The access providers of xdsl traditionally offered data service. And with advances in technology they started to offer a video (TV) service, and lately also a voice-over-packet service to compete with other xdsl providers, with cable operators and with public operators. The deployment of a voice service in the xdsl environment has the same technological background as the voice-over-packet service. With the a voice service can be provided for xdsl service providers. Besides the basic voice service, advanced services can be offered to additionally attract customers and to generate additional revenue. Conference call, forwarding, call transfer and many other services can be deployed to guarantee the same level of voice service that is known from the world. And if a service provider has a good network with an adequate quality of service for voice, the voice-over-packet service offered by xdsl providers has the same level of satisfaction for customers, except for life-line functionality. It is possible to deploy different models for billing within the solution. Besides a flat-rate tariff, prepaid or postpaid deployment for the voice packet service is possible. The and trunk interfaces enable the interconnection of a voice-over-packet service with other service providers to guarantee the ability to connect to voice all over the world. To satisfy the regulations the LIo (SORMo) technology can be used to successfully deploy a fully regulatory compliant solution. The brings the power of NGN technology to xdsl service providers. And the compact form of the simplifies the deployment and maintenance of the solution and guarantees high profitability. uplink, SS7 Addvanced services (VXML, ParlayX, TTS, ASR) Packet uplink, S-T xdsl service provider Packet voice solution for triple play IAD TA Vo terminals Analog terminal

17 Network modernization Because of the deregulation of telecommunications and the development of converged packet technologies, the competition in the telecommunications market is more intense than ever. Traditionally separated dataand voice-service providers are now offering comparable services. This causes price erosion and lower revenues. This is why service providers are trying to optimize their network performance, reduce OPEX and offer new, advanced services to preserve revenues. Optimization of the network is very important, especially for traditional service providers as they have networks that are expensive to expand and operate. And a lot of service providers have already deployed parallel data networks for data services and are now struggling with the operation of two parallel networks and the high costs of operation. That is why service providers are beginning to modernize the network and are starting to deploy a common, converged packet core network. A packet core network has a much higher voice channel density and is easier to operate. Packet technology is in a sense self-routing, as lower layer protocols take care of routing, and thus the operation of traffic optimization is more efficient. Operational savings regarding the deployment of NGN networks are the main driver for network modernization today. Network modernization will not occur overnight on all levels of the network at the same time. Modernization of the whole network is associated with big expenses, with little or no improvements in revenue for some parts of the network. The biggest improvements in revenue with network modernization are expected to be in the large transit plane. The modernization of the network will continue in the rest of the transit plane. The last part of network modernization will be on the small, local plane (rural areas), because of the smaller number of and the long cycles of return on investments. With the the transit network can be modernized with its trunking capabilities. A great deal of signaling support on the side of the enables the modernization of transit networks on all levels of the network, thus providing the maximum protection of previous investments. Because the is fully NGNready, the transition toward a pure NGN with a central call server is straightforward when fully decomposed NGN networks will be ready for large-scale deployment. The NGN protocols integrated into the enable the creation and delivery of new services to end customers based on the latest technologies (Web services, VXML, etc.) for additional revenues for service providers. S-T SS7 Deployment of standalone SI3000 CS (call server) SS7 SIGTRAN SAN Upgrade of SI2000 SAN to S-T V5.2 CAS V5.2 CAS

18 Alternative service provider Telecommunications services were traditionally provided by public service providers. Alternative, privately held service providers started to appear with telecommunications deregulation. Alternative service providers usually deployed the latest technology and new services to attract customers. One of the most common scenarios of deployment for alternative voice service providers today is to buy adequate bandwidth from a data service provider or to build its own data network, and then deploy a voice packet service. This is a cheap alternative to public service providers because data bandwidth today is relatively cheap compared to a public service provider s operation and a cheaper service can be offered. A lot of alternative service providers combine a voice packet service with data services and thus offer a complete telecommunications service. The latter is usually the case for an enterprise solution. A lot of alternative service providers are focused on enterprise solutions. And because they know the technology very well, they are usually able to offer new, advanced services before public service providers. The solution is suited to alternative service provides as it incorporates the latest NGN technology. And because of its compact form it is very cost effective. To satisfy the regulations, the LIo (SORMo) technology can be used to successfully deploy a fully regulatory-compliant solution if necessary. And NGN protocols integrated into the enable the creation of new services based on the latest technologies (Web services, VXML, etc.) for additional revenues for alternative service providers. The Centrex solution within the makes it possible to offer voice packet services to enterprises on the same location and with common equipment, thus reducing the costs and increasing revenues.

19 Summary The convergence of voice and data services is a reality. But the deployment of decomposed NGN solutions is slower than expected. Integrated solutions have emerged to ease the transition toward NGNs. With the, integrated NGN-solution service providers can: Fully protect their previous investments Optimize network performance, thus lowering OPEX Make a smooth evolution toward NGN, as the upgrade to a decomposed NGN solution is straightforward Increase revenues by deploying new, advanced services

20 Abbreviations ASR automatic speech recognition CAS channel-associated signaling DSP digital signal processor DTMF dual tone multi-frequency integrated Call Server ISDN integrated services digital network NGN next generation network OPEX operational expenses POTS RTP plain old telephone service real-time protocol SAN S S-T switch access node session initiation protocol session initiation protocol for telephones SS7 signaling system 7 TTS time division multiplexing text to speech Vo voice-over-internet protocol VPN virtual private network VXML voice extensible markup language Iskratel, Ljubljanska c. 24.a, 4000 Kranj, Slovenija tel.: , fax: info@iskratel.si, http: