Wednesday, February 16, 2011

Next Generation Multi Services Network

Next Generation Multi Services Network is term which does not  have a specific meaning. It offers services like VoIP, IP Telephony, Soft phones, Instant Messaging and Location based services. These services are also accessible from traditional circuit switched networks.

Next-generation multi-service solutions also provide:
  •   Service and technology flexibility
  • Rapid provisioning
  •  Efficient and effective network management, allowing service providers to offer robust service-level agreements (SLAs)
  • A platform that meets the requirements of existing voice and data services and the emerging transmission and application services of tomorrow
The advantages of next-generation multi-service switching are :

  •   Using next-generation multi-service ATM architectures, providers can maintain existing services such as circuit-based voice and circuit-based video, while migrating to and implementing new packet-based network services such as packet voice, Layer 2 and Layer 3 VPNs, MPLS, and MPLS traffic engineering features. Many providers will maintain ATM infrastructures and might need to bridge from a traditional ATM platform to a next-generation multiservice ATM platform.
  •   Multiple service types of ATM, voice, MPLS (Multiprotocol Label Switching ) , and IP are supported on the same physical infrastructure, allowing the provider to leverage both circuit-based and packet-based revenue streams.
  • Control plane independence allows you to upgrade or maintain one controller type independently, without interrupting service for other controllers.
  •   You have the ability to choose and implement a control plane that is best suited to the application requirements.
  •   The separation of the control and switching planes allow the vendor to develop functional enhancements independently of each other.
  •   The cost-effective approach of adding MPLS to ATM switch infrastructure allows for the migration to MPLS as a common control plane.  

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Tuesday, February 15, 2011

Telco Signaling Protocol

There are many signaling systems use in the telecommunications network. There are two essential components to all telephone calls. The first, and most obvious, is the actual content—our voices, faxes, modem data, etc. The second is the information that instructs telephone exchanges to establish connections and route the “content” to an appropriate destination. Telephony signaling is concerned with the creation of standards for the latter to achieve the former. These standards are known as protocols.
SS7 or Signaling System Number 7 is simply another set of protocols that describe a means of communication between telephone switches in public telephone networks. Signaling sytem no. 7 (SS7/C7) is one of the most used system in telecommunication industry for fix line and cellular networks
They have been created and controlled by various bodies around the world, which leads to some specific local variations, but the principal organization with responsibility for their administration is the International Telecommunications Union or ITU-T.
The primary function of SS7 / C7 is to provide call control, remote network management, and maintenance capabilities for the inter- office telephone network. SS7 performs these functions by exchanging control messages between SS7 / C7 telephone exchanges (signalling points or SPs) and SS7 / C7 signalling transfer points (STPs). Basically, the SS7 / C7 control network tells the switching office which paths to establish over the circuit-switched network. The STPs route SS7 control packets across the signalling network. A switching office may or may not be an STP.
The SS7 network and protocol are used for providing intelligent network services such as:
• basic call setup, management, and tear down
• wireless services such as personal communications services (PCS), wireless roaming, and mobile subscriber authentication
• local number portability (LNP)
• toll-free (800/888) and toll (900) wireline services
• 911, 411 services
• enhanced call features such as call forwarding, caller ID display, and three-way calling
• efficient and secure worldwide telecommunications
The current SS7 / C7 network, one of the largest data network in the world, connects together local telcos, cellular, and long-distance networks nationwide and worldwide.
To understand SS7 we must first understand something of the basic inefficiency of previous signaling methods utilized in the Public Switched Telephone Network (PSTN). Earlier all telephone connections were managed by a variety of techniques centered on “in band” signaling.

A network utilizing common-channel signalling is actually two networks in one:

1. First there is the circuit-switched "user" network which actually carries the user voice and data traffic. It provides a physical path between the source and destination.
2. The second is the signalling network which carries the call control traffic. It is a packet-switched network using a common channel switching protocol.

Protocol Structure
SS7/C7 protocol suite covers all 7 layers of the OSI model as showing in the following diagram:

o ASP (Application Service Part)
ASP provides the functions of Layers 4 through 6 of the OSI
o BICC (Bearer Independent Call Control protocol)
BICC is a call control protocol based on ISUP used between serving nodes to support the ISDN services independent of the bearer technology and signalling message transport technology
o BISUP (B-ISDN User Part)
BISUP is an ATM protocol intended to support services such as high-definition television (HDTV), multilingual TV, voice and image storage and retrieval, video conferencing, high-speed LANs and multimedia
o DUP (Data User Part )
DUP defines the necessary call control, and facility registration and cancellation related elements for international common channel signalling by use of SS7 for circuit-switched data transmission services.
o ISUP (ISDN User Parttd)
ISUP supports basic telephone call connect/disconnect between end offices. ISUP was derived from TUP, but supports ISDN and intelligent networking functions. ISUP also links the cellular and PCS network to the PSTN.
o MAP (Mobile Application Parttd)
MAP is used to share cellular subscriber information among different networks.
o MTP (Message Transfer Parttd)
MTP acrosses physical, data link and network layers. It defines what interface to be used, provides the network with sequenced delivery of all SS7 message packets; and provides routing, message discrimination and message distribution functions.
o SCCP (Signalling Connection Control Parttd)
SCCP provides end-to-end routing. SCCP is required for routing TCAP messages to their proper database.
o TCAP (Transaction Capabilities Application Parttd )
TCAP facilitates connection to an external database
o TUP (Telephone User Part)
TUP is an analog protocol that performs basic telephone call connect and disconnect.

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Sunday, February 13, 2011

Voice Gateway

What Is A Voice Gateway

A voice gateway is a device that connects directly to your broadband internet cable modem and allows you to make and receive calls while you're on the Internet. A voice gateway doesn't even come in contact with your computer and does not require that you have a network router connected to your modem to work. Voice gateways allow you to take full advantage of VoIP services without your internet access being interrupted whenever you get a phone call or need to call out.

Voice gateway is a network device that converts voice and fax calls, in real time, between the public switched telephone network (PSTN) and an IP network. The primary functions of a VoIP gateway include voice and fax compression/decompression, packetization, call routing, and control signaling. Additional features may include interfaces to external controllers, such as Gatekeepers or Soft switches, billing systems, and network management systems.

Deployments of voice over IP (VoIP) networks continue at a rapid pace. Voice gateways are an essential part of VoIP networks, handling the many tasks involved in translating between transmission formats and protocols and acting as the interface between an IP telephony network and the PSTN or PBX. Gatekeepers and IP-to-IP gateways help these networks scale. Gatekeepers provide call admission control, call routing, address resolution, and bandwidth management. IP-to-IP gateways allow VoIP calls to traverse disparate IP networks.
The development of Voice-over-IP technology has revolutionized the way telecom does business. By enabling the transportation of voice traffic over data networks, VoIP drives the process of convergence between the public switched telephone networks (PSTN), the Internet and other private IP networks. Such convergence opens up opportunities for providers to offer new services and for users to enjoy significant cost savings.

Working of A Voice Gateway

The device or gateway, which is about the size of a video cartridge, is plugged into your broadband DSL or cable modem. You then attach an ordinary cord or cordless telephone to the gateway and make calls just as you would with the plain old telephone system (POTS).
A voice gateway, also known as a VoIP gateway, plugs directly into your cable modem and intercepts phone calls that are transmitted through your VoIP service. The user plugs a wired telephone or wireless telephone base into the voice gateway once it has been installed on the cable modem. When a phone call is made or received, the voice gateway converts voices into data packets, much like a wireless internet connection does, and then transmits that information across the internet to the other person, where it is then converted back into voice.

  •   Because the gateway bypasses your computer, you can surf the Web at the same time
  •   No software is required.
  •   The gateway can be set up with or without a network router.
  •   You can add additional phone lines from the gateway with an RJ-11(Registered Jack) splitter.
  •   Saves money on long-distance charges,
  •   Better sound quality than afforded by a regular dial-up connection.

If the Internet service is down, the phone will be down along with it.

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Thursday, February 10, 2011

VoIP (Voice over Internet Protocol)

  •  Voice over Internet Protocol (VoIP) is a general term for a family of transmission technologies for delivery of voice communications over IP networks such as the Internet or other packet-switched networks.
  •    Voice information over the Internet.VoIP involves sending voice information in digital form in discrete packets rather than by using the traditional circuit-committed protocols of the public switched telephone network (PSTN).
  •   Other terms frequently encountered and synonymous with VoIP are 
  •  IP telephony,
  •   Internet telephony,
  •   voice over broadband (VoBB),
  •   broadband telephony, and
  •   broadband phone. 
  •   Internet telephony refers to communications services — voice, facsimile, and/or voice-messaging applications — that are transported via the Internet, rather than the public switched telephone network (PSTN).
  • The basic steps involved in originating an Internet telephone call are conversion of the analog voice signal to digital format and translation of the signal into Internet protocol (IP) packets for transmission over the Internet; the process is reversed at the receiving end.
  • VoIP derives from the VoIP Forum, an effort by major equipment providers, including Cisco, VocalTec, 3Com, and Netspeak to promote the use of ITU-T H.323, the standard for sending voice (audio) and video using IP on the public Internet and within an intranet. The Forum also promotes the user of directory service standards so that users can locate other users and the use of touch-tone signals for automatic call distribution and voice mail.
Advantages of VoIP
A major advantage of VoIP and Internet telephony is that it avoids the tolls charged by ordinary telephone service.
  •   Most people use it for free. If you have a computer with a microphone and speakers, and a good Internet connection, you can communicate using VoIP for free. This can also be possible with the mobile and home phone.
  •   When it is used to completely replace the PSTN service, then it has a price. But this price is way cheaper than standard phone calls.
  •    Inexpensive and easy to use. Since it is simple, upgrading is relatively simpler too.
  •    You can integrate it with an existing phone connection.
  •    With VOIP PC-to-PC, calls are free no matter the distance and PC-to-Phone charges are nominal.
  •    For a monthly fee you may make unlimited free calls within a geographic area.
  •    A virtual number enables you to make calls from anywhere as long as a broadband connection is available.
  •    You may purchase a number in a geography area of your choice, which works out very cheap. If your relatives and friends live in Virginia and you moved to California, you may purchase a Virginia number and make local calls to your loved ones.
  •    You may access your VOIP account just like your email Id from any where in the world as long as you have an internet phone. This makes it easy for those who travel frequently to make calls frequently to those back at home at local call rates, no matter where they are.
  •  You may call or message or do both at the same time with VOIP services.

Problems with VoIP
  •   Loss of service during outages.
  •    Without power VOIP phones are useless, so in case of emergencies during power cuts it can be a major disadvantage.
  •    With VOIP emergency calls, it is hard to locate you and send help in time.
  •    Some times during calls, there may be periods of silence when data is lost while it is being unscrambled.
  •    Latency and traffic.
  •    No standard protocol is applicable.
  • The disadvantages of VOIP could be annoying, but their effects are relatively limited. The complaints of VOIP are usually tolerable if the callers are using a free service.
VoIP Protocols
  •  Real-Time Protocol (RTP) for transmitting audio and video packets between communicating computers.
  •   RTP also addresses issues like packet order and provides mechanisms (via the Real-Time Control Protocol, or RTCP, also defined in RFC 3550) to help address delay and jitter.
  •   One of the areas of concern for people communicating over the Internet is the potential a person to eavesdrop on communication.
  •   To address these security concerns, RTP was improved upon with the result being called Secure RTP (defined in RFC 3711).
  •   Secure RTP provides for encryption, authentication, and integrity of the audio and video packets transmitted between communicating devices.
  •   The protocols that are central to this process are referred to as call-signaling protocols, the most popular of which are
  •   H.323 and
  •   Session Initiation Protocol (SIP) and they both rely on static provisioning,
  and other protocols to find other users. 

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Friday, February 4, 2011

Wireless Ip Telephony

Wireless IP Phones
  •   Like on a wired LAN, VoIP can be setup on a wireless LAN.
  •   Wireless VoIP will cause most wired networks to be replaced with wireless networks for VoIP communication.
  •   The caller, who may be using an IP phone or any other communicating device, like a PDA or pocket PC, can make calls through the wireless LAN if he/she is within the range of the network.
Benefits of a Wireless IP Ph
  •   Mobility. This word itself says many things. Just to give examples:
  •   A medical team in a clinic needs to be able to communicate internally and externally while attending to emergencies, which implies being on the move. VoIP on a wireless LAN makes this possible for them, if each of them has a phone in their pocket.
  •   A factory floor team, by nature very ‘bee-like’, will find it difficult to either remain glued to a fixed phone set or going to and from it for communication. Here again, VoIP service deployed on a wireless LAN within the company premises saves time, energy and nerves; and boosts productivity.
  •   VoIP on Wi-Fi hotspots is a great thing for callers. Instead of taking   the laptop computer along for a business lunch or some revision among classmates, one can take the IP Phone or pocket PC along.
Problems with Wireless IP Phones
There are four main issues due to which wireless IP Phones are  not readily accepted everywhere:
  •   Poses problems of scalability for enterprises.
  •   Quality of Service (QoS) is not as good as with wired networks.
  •   The cost, in terms of money, time and skills, is higher to set up and maintain
The security threats posed by the use of VoIP are even more inherent over a wireless network, since access points are more numerous within the perimeter of the network.

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Wednesday, February 2, 2011

Nagpur university syllabus (Revised) MBA 3 rd sem IT

Paper -III: Innovations in IT


Unit I: IT Enabled Services ((ITeS): Outsourcing - India as Ideal Destination, India Outsourcing History, Outsourcing Writing to India, Call Centers in India, Multilingual Call Centers, Voice/Non-Voice ITeS (BPO Services), HIPAA Compliance in India, Outsourcing Engineering Services, Radiology and Intellectual Property to India. BPO: BPO Concept, Offshoring, Nearshoring, Homeshoring, Medical / Legal Transcription, Back-Office Accounting, Insurance Claims, Credit Card Processing, BPO in India, BPO Security, BPO in India - Legal Issues
Unit II: Ntewroking Technology &Systems (NeTS) - Next Generation Multi-service Networks, Future INternet Design (FIND), IP Telephony (IPT): IPT Components, Soft Phones, Wireless IP Phones, Voice Gateways, Inter-cluster Call, Telco Signaling Protocols, VoIP, VoIP Protocols, Large-Scale IPT and Voice-Mail Network: Voice Network Architecture, Overview: Network Planning and Designing.

Unit III: Communication Technologies-I - Next Generation Mobile Networks, Heterogeneous Networks, Ad-Hoc & Sensor Networks, Wireless Networks: WiFi, WiMax, Cellular, 3G/4G.

Unit IV: Communication Technologies-II - Mobility Management and Mobile Computing, Technology Convergence: GSM/CDMA/TDMA, Quality of Service Issues, Network Security and Privacy, Grid Computing and Clustering, Mobile TV, MMIT.

Unit V: Web Applications and Services-I - Internet Services and Applications, Web Services, Internet Computing, E-Learning , Middleware , Web Information Systems.

Unit VI: Web Applications and Services-II - Web Based Software, Semantic Web, Agent-Oriented Computing, E-Business, E-Commerce & E-Government, Ontology Engineering, Portal Technologies.

Unit VII: Computing and Information Systems - Advanced Computer Architectures, Virtual Reality, Databases & Data Mining, Agile Information Systems, AI & DSS, High Performance & Cluster Computing, Real-Time and Embedded Systems, Information Systems Integration , Geographical Information Systems, Business Process Modeling.

Unit VIII: Pervasive and Ubiquitous Computing-I - Smart Appliances & Wearable Computers, Inter-Vehicular Communication, Personal Computing, Pervasive Wireless Networking, Opportunistic Systems, Ubiquitous Health Care.

Unit IX: Pervasive and Ubiquitous Computing-II - Ubiquitous Computing, Location-Based Services, Educational Gaming & Instructional Technologies, Context-Aware Environments and Devices, Personal Broadcasting, Autonomic Systems.

Unit X: IT Trends - Biometrics, Fuzzy Logic & Neural Networks, Organic Growth, Audio/Visuals: mp3, mpeg and IPOD, General Outline of IT Act’2000, Case Studies: Mobile Industry Market Players: Nokia, Motorola, Sony-Ericson, Samsung and LG.  GIS: Google Earth, E-Learning: Zee TV, E-Governance: Andhra Pradesh, Gadgets: Apple Store, Networking: Cisco.

Suggested Readings:
1.        Offshore Ready: Strategies to Plan & Profit from Offshore IT-enabled Services by Stuart Morstead
2.        Networking Infrastructure for Pervasive Computing: Enabling Technologies and Systems by Debashis Saha, Amitava Mukherjee, and Somprakash Bandyopadhyay
3.        Introduction to Mobile Communications: Technology, Services, Markets (Informa Telecoms & Media) by Tony Wakefield, Dave McNally, David Bowler, and Alan Mayne
4.        iPod & iTunes: The Missing Manual, Fourth Edition by Jude Biersdorfer
5.        Developing Web Services for Web Applications: A Guided Tour for Rational Application Developer and WebSphere Application Server (IBM Illustrated Guide Series) by Colette Burrus and Stephanie Parkin

Dear friends,

I have uploaded the 8th and 9 th unit topics from the syllabus in my blogs. 

Unit 2 -
Networking technology and Systems

you can go through the blogs and tell me if you want more information.

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Friday, January 14, 2011


  •  A softphone is an application that runs on a general purpose device and provides IP phone capabilities.
  • A softphone is asoftware which provide the facility of telephone calls on the internet by using any common computer without using any dedicated hardware.
  • Commonly the use of softphones is not suggested. First the security and availability of the softphones is depend on the underlying device.The common purpose nature of the device may endanger voice services.
  •  Secondly, the use of softphones also violate the IPT phone and security zones restrictions.
  • When there is need then softphones should be used as a secondary communication means.
  • A softphone is usually used with a headset connected to the sound card of the PC or with a USB phones.
  •  A separate security zone is established for devices which are using softphones .
  • A typical softphones has all normal telephony feature like mute, flash, hold, or transfer, etc. and many new ones like wideband, audio, video, etc.
  • For communication using softphones both the endpoints must have the same communication protocol.

  •  Application of softphones are:
           a> A usual application of softphone is to make calls via an internet
                telephony service provider to other softphones or to telephones.

           b> There are three internet telephony service providers having their own
                 softphones that you install on your computer , these are Skype,
                 Google talk and Vonage.These providers are not interoperable
                 and you cannot place a direct call between them.

  •  Requirements of softphones are :
             a> In internet connectivity like DSL, WiFi Cable or LAN .28.8 dial up 
                  modem are enough if want to use.
             b> In any modern PC with a headset or with USB phone, or with a 
                  microphone or speaker.

For more notes you can also refer to other links as given below: