JTO Phase II Data Network & IT PDF

JTO Phase II Data Network & IT NGN 11 NGN 11.1 Learning Objectives After reading this chapter, you should be able to understand: General overview of NGN. NGN Architecture....

JTO Phase II Data Network & IT NGN 11 NGN 11.1 Learning Objectives After reading this chapter, you should be able to understand: General overview of NGN. NGN Architecture. NGN Services. Services provided by NGN Components. 11.2 Introduction Telecommunication industry is changing at a rapid pace. This change in the industry is basically driven by demand of new services from subscriber's side and urge to reduce CAPEX (Capital Expenditure) and OPEX (Operational Expenditure) from carrier side. Today All most all telecommunication giants are installing and maintaining at least three kinds of basic Network. 11.2.1 PSTN: Public Switch Telephone Network was basically developed and engineered for giving voice connectivity to the wire line subscribers. The network consists of Local exchange/RSU as a part of Access Network and TAXs as a part of core Network. Already huge amount of money has been invested in PSTN setup. Because of tough competition from Mobile & Voice over IP, it is becoming white elephant day by day for the operators. Another fact about PSTN is that most of its equipment are going to exhaust their lives in coming years. 11.2.2 PLMN: (Public Land Mobile Network): PLMN has been developed to provide voice services for wireless subscribers. Though in recent times SMS has emerged as killer application for mobile. PLMN includes BTS/BSC as access network and MSC as a core Network. 11.2.3 Data Network: This network was basically designed for accessing remote files and servers for defense people and universities but now a days nobody can think of living with data network services. The basic and most popular application of data networks is Internet. Other applications include E-commerce, online banking, online gaming, E-shopping, IPTV Video on demand and many more. Data network is an assembly of routers, which are responsible for forwarding information from one end to other. The interesting fact about the current generation is that these networks have been developed during different time zones. That‘s why they are separate network infrastructure. There is no sharing of infrastructure among them. However some gateways are available for inter network communication. Another disadvantage of the current scenario is that all the three networks are having their own service platforms in other words services are tightly coupled with their networks JTO Phase II (DNIT) Version 1.0 Sep 2021 Page 146 of 174 For Restricted Circulation JTO Phase II Data Network & IT NGN because of that carrier or operators have to introduce service separately for separate networks. Because all the three networks are having separate access transport and switching network service provider has to invest in all the three networks separately. Hence CAPEX increases on the other hand for maintenance of three different networks operational cost also increases. Manpower of the company has to have knowledge of multiple technologies. NGN Vision: Next Generation Network is the framework where operator will have a common transport network based on Internet Protocol for providing all kinds of telecommunication services. Hence operators will have to install and maintain only a single network which will reduce its CAPEX and OPEX significantly. Moreover service provisioning will become easier because of the introduction of new and intelligent servers. NGN is able to provide Vendor independence because of the standard protocols it uses for interaction with network elements. NGN Definition A Next Generation Network (NGN) is a packet-based network able to provide Telecommunication Services to users and able to make use of multiple broadband, QoS- enabled transport technologies and in which service-related functions are independent of the underlying transport-related technologies. It enables unfettered access for users to networks and to competing service providers and services of their choice. It supports generalised mobility which will allow consistent and ubiquitous provision of services to users. [ITU-T Recommendation Y.2001 (12/2004) - General overview of NGN] In the above definition all the terms are self explanatory except Generalized mobility. Generalised mobility: At present subscribers are enjoying terminal mobility where network identification system is available in the form of SIM and the same is inserted in the terminal. If user is having that terminal he will be mobile with the identity of the SIM. In NGN subscriber can have Generalised mobility. Here each individual will have its own network identity in the form of "SIPURL: xyz @ domain name.com". Users have to make registration from his devices against the given URL. Registrar servers of the company will maintain bindings with URL and physical location of registered devices. Users can register for more than one device at a time. With this subscribers need not to depend upon terminal they can login with any device enabled with required protocols (SIP) if they want and call will come to that device. 11.3 NGN Architecture NGN is a layered architecture consisting of transport, access, control and application layer. It is important to note that all the layers are independent from each other. Change in one layer should not affect other layers. 11.3.1 Access Layer: Access Layers is responsible for direct subscriber attachment function. NGN can support all kind of existing access as well as upcoming access. In fact NGN does not matter about type of access. NGN is capable of processing traffic originated from PSTN, GSM, CDMA, xDSL, WiMAX or any other access system. Depending upon the type of JTO Phase II (DNIT) Version 1.0 Sep 2021 Page 147 of 174 For Restricted Circulation JTO Phase II Data Network & IT NGN access, protocol conversion and/or media conversion may be required at the NGN Gateways. Access Layer consists of Gateways. Example of getaways are media Gateway, Access gateway. Signalling gateway. Media gateway terminates media, coming from PSTN/PLMN in E1 / STM. Here it is responsible for packetisation of media under the instruction of control layer. After packetisation of information it throws packets to the transport Network. Access gateway is nearer to subscriber. Subscriber can directly be terminated in Access Gateway. All the required configuration of such subscribers should be done at control layer. Access Gateway and Media Gateways are responsible for carriage of Media whereas Signalling gateway is carrying signalling generated by PSTN and informs Control Layer about the signalling in required format. 11.3.2 Transport Layer Transport Layer of NGN is based on IP. It can utilize the advantage of MPLS. Transport Layer forms the core of the Network. It basically consists of Routers, which are responsible for carrying traffic originated by access layer. As the same core network is going to be used for all kinds of subscribers enjoying different kind of real time and non real time services, it should be able to make use of band width policies and Qos policies. Operator has to think of managed Network for its subscribers. Figure 59: NGN Architecture It is basically an assembly of routers connected with optical network. Traffic coming from gat ways is properly routed by those routers. 11.3.3 Control Layer It is responsible of call setup, routing and charging policies and other controls in NGN environment. It consists of call servers where all information of the network resides. These call servers are responsible for setting up, modifying, charging and tear down of the calls. NGN may work on soft switch principle. It consists of MGC (Media Gateway Controller) as an overall controller and MGs(Media Gateway) for termination of traffic. MGC is basically a server and it is having all the necessary information of network MGC instructs MGs for establishing the call. Under the control of MGC, MG performs different JTO Phase II (DNIT) Version 1.0 Sep 2021 Page 148 of 174 For Restricted Circulation JTO Phase II Data Network & IT NGN call related tasks such as connection, modification and termination of media streams, packetisation of media etc. 11.3.4 Application Layer It is responsible for OSS/BSS. Enhanced services to the subscribers will be provided with the help of application servers. It may include prepaid servers, announcement servers, Service servers etc. Hence NGN is making service separation from Network. Any service can be introduced with the help of server at any time without any modifications in the control, transport or access. 11.4 PSTN versus NGN:  As shown in above figure PSTN Switch consists of interface, Switching and call control. All the functional entities are shown in one box that means they are interacting with each other using proprietary protocol. Where as in NGN model entities are interacting using standard protocols. Figure 60: PSTN versus NGN  In PSTN each node should have call control separately whereas NGN may have centralized call control  PSTN is dedicated network for providing voice services to the subscribers whereas NGN is developing with the idea of carrying all kind of traffic over it.  PSTN is working on circuit switched principle whereas NGN is working on Packet switching.  PSTN provides excellent quality of voice and it is tested in all conditions whereas NGN will provide good quality of voice and it is to be tested in adverse network conditions. JTO Phase II (DNIT) Version 1.0 Sep 2021 Page 149 of 174 For Restricted Circulation JTO Phase II Data Network & IT NGN  In PSTN service integration is very difficult and because of vendor dependent technologies it is difficult to introduce services easily. Whereas NGN shall be able to provide separate service platform for introduction of services without depending upon underlying network related technologies. 11.5 NGN Services NGN is a horizontally layered network as compared to the conventional vertically separated networks for each service. The access, transport, control and service functions are separated into individual network layers. These layers can be managed by different service providers. Thus third party service providers can develop and offer innovative personalised services to the end users. NGN uses Internet Protocol (IP) based transport for all services including voice thereby service provider‘s CAPEX and OPEX are reduced. Figure 1 depicts various services supported by NGN. A brief description of various services provided in NGN is given below: Figure 61: NGN Services  Voice Telephone Services: NGN supports all existing PSTN/ISDN/PLMN voice telephony services like Call Forwarding, Call Waiting, 3-Way Calling, Calling number and name Identification Presentation, Centrex services, various IN services and other value aided services. JTO Phase II (DNIT) Version 1.0 Sep 2021 Page 150 of 174 For Restricted Circulation JTO Phase II Data Network & IT NGN  Multimedia Services: These services allow customers to converse with each other while displaying visual information. It is possible for multiple parties to interact each other using voice, video, picture and data. Multimedia services include video conferencing, multimedia value added services, collaborative computing, groupware, electronic white boarding etc. An electronic whiteboard is an application where both parties can write and draw on the same picture for discussion during a multimedia call. This is useful for remote teaching, technical discussion etc.  Data Services: Data services establish real-time connectivity between endpoints along with various data related value-added features (e.g., bandwidth-on-demand, connection reliability/resilient Switched Virtual Connections (SVCs) and bandwidth management/call admission control). Data services include file transfer, www, applications sharing interactivity etc.  Messaging Services: NGN supports both real time and non-real time messaging services for fixed and mobile networks. Some messaging services are designed as ‗real time‘ and others are ‗non-real time‘ (mailbox) service where the messages are stored and delivery at a later time. i) Unified Messaging: Unified Messaging facilitate the delivery of voice mail, email, fax mail etc. through common interfaces. Through these interfaces, users can access, as well as can be notified of, various message types (voice mail, email, fax mail, etc.), independent of the means of access (i.e., wireline or mobile phone, computer, or wireless data device). ii) Instant messaging (IM): Instant messaging (IM) is a form of real-time communication between two or more people based on typed text. Instant messaging is supported across fixed and mobile networks. The key features of instant messaging are low latency, security, mobility, group management and message filtering. iii) Chat: This facilitates real-time communication by means of text between two terminal users who have already logged on. iv) MMS and SMS: This facilitates near real time communication by sending and receiving multimedia messages or text messages. For example video greetings that can be sent using MMS.  Push to talk over NGN (PoN): 'Push' operation refers to service initiated data transmissions to members of a group. Push-to-Talk, also referred to as PoC (Push- to-Talk over Cellular) is built around VoIP (Voice over IP) technology. It is a wireless service that turns mobile phones into long-range walkie-talkies by connecting to other phones without dialling. Instead of dialling, one can simply push a button and talk to members of a group. The speech will be one-way-at-a- time instead of a two-way conversational mode. It can be used for short-duration and high-urgency voice communications and keeps an ‗always-on‘ connection between groups of frequently called mobile subscribers like family, colleagues, business associates etc. All members of the group can hear the speech from others. The listeners do not have to press any button to hear the speech from others and it is always on. JTO Phase II (DNIT) Version 1.0 Sep 2021 Page 151 of 174 For Restricted Circulation JTO Phase II Data Network & IT NGN  Content delivery services: Content based services like music and video on demand, radio streaming, gaming, financial information distribution, professional and medical image distribution, electronic publishing etc. can be provided to customers.  Global Mobility Services: In NGN environment phone and other devices user can travel from place to place. Global Mobility Service provides global roaming and other location based services for all types of wireless and wireline subscribers. Mobility can be for terminal, user and services. Terminal mobility is the ability of a terminal to be moved to different access points.  Number Portability: Number Portability provides the end users to retain existing directory numbers while moving from one physical location to another or from one service provider to another.  Virtual Private Networks (VPNs): Voice VPNs improve the multiple location networking capabilities of businesses by allowing large, geographically dispersed organizations to combine their existing private networks with subsets of PSTN, thus providing subscribers with uniform dialing capabilities. Data VPNs provide added security and networking features that allow customers to use a shared IP network as a VPN.  Broadcasting/ Multicast Services: These Services involve transmission of data to many users simultaneously, allowing efficient use of bandwidth, like radio broadcast, TV broadcast. For example IPTV (Internet Protocol Television) is used for delivering digital television services using the Internet Protocol (IP) using wireline as well as wireless broadband connections. The user terminals might be a PDA, Laptop, mobile handset, TV etc.  Emergency Telecommunication Services: Emergency services are provided between citizen to authority, authority to authority and authority to citizen. Typical emergency services are Police/medical assistance , Disaster relief operations , Lawful intercept services etc.  e-Commerce & m- Commerce: These services allow consumers to purchase goods and services electronically over the network. This includes processing the transactions, verifying payment information, providing security and possibly trading (i.e. matching buyers and sellers who negotiate ―trades‖ for goods or services). Home banking, home shopping, Business-to-business applications (e.g. supply-chain management and knowledge management applications) are also part of these services.  Remote control/tele-action services: These services are used for home applications control, telemetry, electronic voting, alarms etc. With the advent of in-home networking and intelligent appliances, these services could monitor and control home security systems, energy systems, home entertainment systems, and JTO Phase II (DNIT) Version 1.0 Sep 2021 Page 152 of 174 For Restricted Circulation JTO Phase II Data Network & IT NGN other home appliances. For example if some one is watching television and the doorbell rings, he can use the TV‘s remote to get a view of the entrance to see who‘s there. Another example is monitoring the house while away on a trip.  Information Services/ Information Brokering: This service is also called voice portal service. These services include news, sport scores, weather, stock quotes, advertisement, directory enquiry service, cinema ticket, motorway traffic status and information to consumers based on pre-specified criteria or on personal preferences.  Call Center Services: A subscriber can make a call to a call center agent by clicking on a Web page or CPE. The call is routed to an appropriate agent, who could be located anywhere, even at home (i.e., virtual call centers). Voice calls and e-mail messages can be queued uniformly for the agents. Agents would have electronic access to customer, catalog, stock, and ordering information, which could be transmitted back and forth between the customer and the agent.  Session Controller-based Internet services: It provides access to public Internet through existing mechanisms. Internet services are provided by the access network of NGN.  Third party/OSA-based services: NGN provides open API interface for third party or person to develop personalised services: Third party/OSA-based services are applications developed and provided by vendors outside the service provider‘s domain using IT technology and tools. Parlay is an open standard API designed to facilitate easier access to core network capabilities from outside of the network. Such API allows the existence of new business models. 11.6 SERVICES PROVIDED BY SOFTSWITCH  Abbreviation Dialling: Abbreviated dialing is the use of a short telephone numbers to reach public services. Typically these are two or three digits.  Absent Subscriber Service: This feature makes possible for a subscriber who cannot answer the calls, because he/she is absent, to divert these calls to an announcement  Advice of Charge: This service provides the end user with information about the costs of a call and the accumulated charges on the end users call meter counters.  Anonymous Call Rejection: The Anonymous Call Rejection service enables a user to reject calls from anonymous parties who have explicitly restricted their Caller ID. By activating the service, callers without available caller identification are informed that the user is not accepting calls at that time. The user's phone does not ring and the user sees or hears no indication of the attempted call.  Auto Call back: When the calling person is engaged, calling part can register for Auto Call back by inserting a specified button or key on the calling instrument. It JTO Phase II (DNIT) Version 1.0 Sep 2021 Page 153 of 174 For Restricted Circulation JTO Phase II Data Network & IT NGN is not possible to place an automatic call back if the called number is diverts to voicemail. As soon as the called party hangs up, a call will set up automatically from caller to the called party - both r phones will ring. This feature saves time and network resources to keep trying the same number over and over.  Automatic Alarm Ring Service: This feature allows a subscriber to set an alarm call or reminder call on his phone. At the specified time a call is made to the subscriber and an announcement is fed on receiving the call. If the subscriber does not answer the phone within one minute (or ringing time out which ever is later) or if the subscriber is busy, the alarm call will be repeated 5 minutes later. If the repeat attempt is also unsuccessful, a report is produced on the suitable media and request cancelled.  Automatic Hold/Retrieve: The Automatic Hold/Retrieve service provides an alternate method to hold and retrieve calls for System users. Specifically, service can be setup where calls are held without having to use feature access codes. The service is especially useful to attendants handling large volume of incoming calls by allowing them to hold calls by simply transferring them to dedicated parking stations.  Call Forwarding Busy: Call Forwarding Busy enables a user to redirect calls to another destination when an incoming call encounters a busy condition. The user can activate and deactivate the service. If activated, a user must specify the forwarding number.  Call Forwarding Immediate: Call Forwarding Always enables a user to redirect all calls to another destination. The user can activate and deactivate the service. If activated, a user must specify the forwarding number.  Call Forwarding No Answer: Call Forwarding No Answer enables a user to redirect calls to another destination when an incoming call is not answered within a specified number of rings. The user can activate and deactivate the service. If activated, a user must specify the forwarding number and the number of rings before forwarding.  Call Forward on Not Reachable (CFNR): Call forwarding on not reachable enables the user to redirect calls to another destination (Phone number, voice mail) when an incoming call encounters a not reachable condition. The user can activate and deactivate this service through an activation/deactivation procedure. The caller status can become unreachable in case of power failure or LAN cable disconnection.  Call Forwarding Remote Access: Call Forwarding Remote Access enables users to activate, deactivate, and program their Call Forwarding service from any phone.  Call Forwarding Selective: Call Forwarding Selective enables a user to define criteria that causes certain incoming calls to be redirected to another destination. If JTO Phase II (DNIT) Version 1.0 Sep 2021 Page 154 of 174 For Restricted Circulation JTO Phase II Data Network & IT NGN an incoming call meets user specified criteria, the call is redirected to the user specified destination. The user controls the service via an interface, which provides the ability to set the forwarding destination address and the criteria sets for determining which calls require forwarding. A criteria set is based on incoming calling line identity, time of day, and day of week. Multiple criteria sets can be defined and a different forward-to number can be set for each.  Call Hold: This allows the user to place a caller on hold and make another call to some other number.  Call Intercept: Call Intercept records the call contents and identity and gives several options for handling the call.  Call Return: Call Return enables a user to call the last party that called, whether or not the call was answered. To call back the last party that called, the user dials the call recall star code. The system stores the number of the last party to call, and connects the user to that party.  Call Waiting: Call Waiting enables a user to answer a call while already engaged in another call. When a second call is received while a user is engaged in a call, the user is informed via a call waiting tone. To answer the waiting call, the user depresses the flash hook. The user connects with the waiting party and holds the original party. By depressing the flash hook, the user reconnects to the original party and holds the waiting party. The feature completes when any party hangs up. Users can activate/deactivate the Call Waiting service for all incoming calls via their web interface. Users also have the option of canceling their Call Waiting on a per-call basis by dialing a star code before making the call, or after a switch- hook flash during the call. Once the call is over, Calling Waiting is restored.  Calling Line ID Delivery: Calling Line ID Delivery enables the delivery of a caller's identity. Delivered information includes the caller's phone number and name. The information is delivered to the web interface and the phone (if capable) only if the information is available and has not been blocked by the caller.  Carrier pre-selection: Carrier Pre-Selection (CPS) is a mechanism that allows end-users to select, in advance, alternative Service Providers to carry their calls without having to dial a prefix or install any special equipment at their premises.  Centrex Facility: Centrex facility provides a virtual PABX facility for group of subscribers.  Closed User Group: A Closed User Group is a logical group within the operator‘s network. Users belonging to a ‗Closed User Group‘ are permitted to communicate with each other but not with users outside the group. A user data terminal equipment (DTE) may belong to more than one closed user group. JTO Phase II (DNIT) Version 1.0 Sep 2021 Page 155 of 174 For Restricted Circulation JTO Phase II Data Network & IT NGN  Dial-up Call: It is for connecting a network connection, e.g. Internet, which requires a telephone number to be dialled.  Direct Inward/Outward Dialling: This feature is applicable for Centrex or PABX users. Users can be assigned a directory number that can be used to place/receive calls directly from/to their phone, without forcing access via a central number. Incoming and outgoing calls can be placed/received via the phone or the Call Manager (except an initial incoming call, for which the phone must be taken off hook).  FAX Call: Point-to-point FAX and Multi-point FAX services are supported.  Immediate and Timed hot line: When a subscriber goes off hook or sends calling condition to the switch, the switch sets up immediately or after a specified delay period (within the delay period the subscriber will be able to initiate a normal call), a connection to a predetermined telephone number. The number registration can be done either by the subscriber, or, on request, by the administration.  Incoming Call only: This facility restricts the user to receive incoming call only.  Malicious call trace: Malicious Call Trace enables a user to request, the calls which have been received to be automatically traced by dialling a feature access code after the call.  Missed Call Notification (MCN): This service provides the subscriber details of missed call or message received by him. Based on calling line identification presentation (CLIP) and short message service (SMS), missed call notification is sent to the subscriber.  Non Metered Call: This facility enables certain numbers as toll free number. Calls made to these numbers are not charged.  Outgoing Call only: This facility restricts the user to make outgoing call only.  O/G Call Restriction Service or Subscriber controlled dynamic STD/ISD: This feature enables a subscriber to bar certain O/G directions from his telephone line. The types of barred directions are prescribed by the administration, and the subscriber can activate and deactivate them. The subscriber can also activate and deactivate the service by registering secret password which can be changed by the subscriber.  Pay Phone/Coin collecting Box Service: This feature allows calls from special telephone instrument (called CCB PCO) permitting O/G calls after insertion of adequate coin(s), token or coded cards, and I/C calls without payment. O/G calls to certain services (e.g. emergency service) may be admitted without payment. JTO Phase II (DNIT) Version 1.0 Sep 2021 Page 156 of 174 For Restricted Circulation JTO Phase II Data Network & IT NGN  Priority Lines: This feature allows some lines in the exchange to be marked as priority lines. These lines get preference while originating calls, in case of abnormal conditions like switch overload or network congestion. This feature can be useful for individuals or services more responsible for the maintenance of law and order and security of the citizens, under emergency conditions.  Selective Call Services: This service allows the end-user to give special treatment to calls originating from a pre-defined list of subscriber numbers. The result of this treatment can be either differentiated ringing (for different members of a family) or rejection of non-expected calls.  Voice Mailbox Service: This service implements all functionality needed to the end user to complete call answer service. Not answered incoming calls are redirected to a voice mailbox, where the caller may leave a message. The end-users are then informed that a message is waiting in the Mailbox and can retrieve it. Messaging services give end user the advantages of the telephone answering machine without owning one. 11.7 SERVICES PROVIDED BY EXTERNAL APPLICATION SERVER  Application sharing: Application Sharing is an element of remote access, that enables two or more users to access a shared application or document from their respective computers simultaneously in real time. Generally, the shared application or document runs on a host computer and remote access to the shared content is provided to other users by the host user.  Call Notification: Call Notification enables a user to define criteria that causes certain incoming calls to trigger an e-mail notification. If an incoming call meets user specified criteria, an e-mail (or short message to a cell phone) is sent to the notify address informing the user of the details of the incoming call attempt. The user controls the service via a web interface, which provides the ability to set the notify e-mail address and the criteria sets for determining which calls trigger a notification. A criteria set is based on incoming calling line identity, time of day and day of week. Multiple criteria sets can be defined.  e-commerce/m-commerce: e-commerce (electronic commerce) and m-commerce (mobile commerce) are the services on the Internet (especially the World Wide Web) and on mobile phone for buying and selling of goods and services.  e-learning: e-learning or Electronic learning refers to computer-enhanced learning. It consists of links to selected and reviewed articles, white papers, research reports, journal articles, conferences, workshops, seminars etc. JTO Phase II (DNIT) Version 1.0 Sep 2021 Page 157 of 174 For Restricted Circulation JTO Phase II Data Network & IT NGN  Electronic publishing/Information Services: This service provides news, financial matters, travel information, movie trailers, sales, promotion etc. on user terminal.  Electronic white boarding: An Electronic white board is a computer-based, distributed, shared graphical and text working space. One useful application of Electronic white board is for distance learning.  Gaming Content delivery service: This service delivers online multiplayer gaming on PC, Mobile phone etc.  Instant Messaging: Instant messaging (IM) is a form of real-time communication between two or more people based on typed text. The text is conveyed via computers connected over the network.  Location-based services: Location-based services allow global roaming and other location related applications. For example while negotiating a deal on the phone, the other party asks to fax some information. A location-based service then direct to the nearest public fax machine available. One can request for weather forecast and receive the forecast for the place where he is. Laptops or Pocket PCs installed into ambulances, fire brigade, radio taxies, cable TV repair mobile centre etc. could be more efficiently routed to their next destination.  Multimedia conference: It is the multi-party interaction with each other using voice, picture, video and data file.  Push to Talk over NGN: Push to talk over NGN is an IP based half-duplex voice service for easy-to-use ―walkie-talkie‖ style communication for the customers.  Radio Streaming/ Music on Demand (MoD): Radio streaming is audio transmission over a data network to deliver audio on demand or an audio broadcast. Unlike sound files (WAV, MP3, etc.) that are played after they are downloaded, streaming audio is played within a few seconds of requesting it, and the data is not stored permanently in the audio play device. Music-on-Demand enables individuals to select audios from a central server for listening music on computer or any other audio device.  SMS/MMS Service: Multimedia Messaging System is a communications technology developed by 3GPP that allows users to exchange multimedia communications between capable mobile phones and other devices. An extension to the Short Message Service (SMS) protocol, MMS defines a way to send and receive, almost instantaneously, wireless messages that include images, audio, and video clips in addition to text. A common current application of MMS messaging is picture messaging (the use of camera phones to take photos for immediate delivery to a mobile recipient). JTO Phase II (DNIT) Version 1.0 Sep 2021 Page 158 of 174 For Restricted Circulation JTO Phase II Data Network & IT NGN  TV Broadcast: In traditional television delivery, all programmes are broadcasted simultaneously. The available program signals flow downstream and the viewer selects the program to watch by changing the channel. IPTV, by contrast, sends only one program at a time. Content remains on the service provider's network and only the program the customer selects is sent to the home. When a viewer changes the channel, a new stream is transmitted from the service provider's server directly to the viewer.  Unified Messaging: Unified messaging (sometimes referred to as the unified messaging system or UMS) is the handling of voice, fax, and regular text messages as objects in a single mailbox that a user can access either with a regular e-mail client or by telephone. The PC user can open and play back voice messages, assuming their PC has multimedia capabilities.  Video Streaming/ Video on demand (VoD): Video streaming is a video transmission over data network to deliver video-on-demand or a video broadcast service. Unlike movie files (MPG, AVI, etc.) that are played after they are downloaded, streaming video is played within a few seconds of requesting it, and the data is not stored permanently in the video play device. Video-on-Demand enables individuals to select videos from a central server for viewing on a television or computer screen.  Web browsing: Web browser is a software application used to locate and display Web pages. The two most popular browsers are Netscape Navigator and Microsoft Internet Explorer. Both of these are graphical browsers, which mean that they can display graphics as well as text. In addition, most modern browsers can present multimedia information, including sound and video, though they require plug-ins for some formats. Subscribers can control their subscribed services through Web Portal. Following services can be invoked via the web portal: (a) Click-to-dial (b) Call Answer (c) Call Hold/Retrieve (d) Call Release (e) Call Transfer (f) Three-way Conference 11.8 Conclusion: It is very much clear that NGN is a network, which can help operators for their needs. But at the same time operators have to invest in NGN wisely because of the fact that some past technologies like ISDN made so many promises but could not meet them properly. Same should not happen to NGN. Instead of depending upon any specific model (like Softswitch or IMS), NGN should be treated as an approach towards complete IP communication. Operators should have flexibility for implementing any kind of model on need basis. JTO Phase II (DNIT) Version 1.0 Sep 2021 Page 159 of 174 For Restricted Circulation