Voice over IP By SAIKIRAN PANJALA
- 1. Voice over IPVoice over IP NAME:@@@@@@@@@@@@@ HT NO:1246hjjjjj Under the guidance of @@@@@@@@@
- 2. Contents Abstract Introduction What isVoIP HowVoIP works VoIP Architecture Components Conclusion References
- 3. Abstract With the aim of reducing communication costs, efforts of integrating voice and data networks have been a rising priority for many companies. Organisation have been working on the solutions which would make the use the excess capacity on broadband networks for voice and data transmission ,as well as utilize internet and company intranet as alternatives to expensive systems. At the same time more and more companies are seeing the value of transporting voice over IP networks.
- 4. INTRODUCTION Voice over IP (VOIP), otherwise known as IP telephony, is the delivery of voice information over Internet Protocol (IP) packet switched networks. This means sending voice information in digital form in discrete packets rather than in the traditional circuit-committed protocols of the public switched telephone network (PSTN).A major advantage ofVOIP is that it can avoid the tolls charged by ordinary telephone service by utilising fixed charge IP network services such as broadband. Recent development with SIP (see below) technology and hardware supporting this standard has resulted in the production of a number of commercially marketed SIP handsets, both wired and wireless networks, removing the need for a PC or laptop running a software handset, or “softphone”, to connect toVOIP services.A subscription to a local server from a SIP handset or softphone provides you with all the normal telephony features including voice and fax, as well as text and even video services.
- 5. What is VoIP? VoIP is packetisation and transport of classic public switched telephone system audio over an IP network. It allows 2-way voice transmission over broadband connection. It is also called IP telephony, internet telephony, voice over broadband, broadband telephony.
- 6. PSTN vs. INTERNET PSTN Voice network use circuit switching. Dedicated path between calling and called party. Bandwidth reserved in advance. Cost is based on distance and time. INTERNET Data network use packet switching. No dedicated path between sender and receiver. It acquires and releases bandwidth, as it needed. Cost is not based on distance and time.
- 7. PBX Yesterday’s Networks Circuit Switched Networks (Voice) CO PBX CO CO Packet Switched Networks (Data) Router Router Router Router Router • Separated networks • Separated applications/services
- 8. PBX IP Phone Converged Network PSTN CO Gateway Router Router Router Router • Converged network • Separated or integrated applications PBX IP Phone
- 9. VoIP – How does it work? Converting the voice signal ADC (analog to digital) DAC (digital to analog) Voice (source) - - ADC - - - Internet - - - DAC - -Voice (dest) Transmission of voice traffic in packets
- 10. VoIP – How does it work? The 1-2-3s of VoIP 1. Compression – voice is compressed typically with one of the following codecs, G7.11 64k, G7.29AB 8k, G723.1 6.3k 2. Encapsulation – the digitized voice is wrapped in an IP packet 3. Routing – the voice packet is routed thru the network to its final destination
- 11. LT S©Telcordia Technologies, Inc. Slide 11 IP Network Multimedia PC Multimedia PC Initially, PC to PC voice calls over the Internet VoIP Architecture? PSTN (DC) Gateway PSTN (NY) Gateway Public Switched Telephone Network Gateways allow PCs to also reach phones …or phones to reach phones
- 12. Components VoIP Protocols VoIP Gateway VoIP Codecs
- 13. VoIP Network Model SIP RTP, RTCP, RTSP Transport Layer (UDP, TCP) Network Layer (IP, IP Multicast) Data Link Layer Physical Layer
- 14. PURC IP Protocol LayeringIP Protocol Layering Physical Transport (e.g, Cable Modem) IP (Internet Protocol) TCP UDP Applications (e.g., email, web pages) Email Data (1000 bytes)TCP Header (20 bytes) IP Header (20 bytes) A Typical IP Datagram
- 15. VoIP SIP
- 17. VoIP Gateway A VoIP gateway is a gateway device that uses Internet Protocols to transmit and receive voice communications (VoIP).
- 18. VoIP Codecs Codecs are used to convert an analog voice signal to digitally encoded version. Codecs vary in the sound quality, the bandwidth required, the computational requirements, etc.
- 19. Do Companies Want VoIP? 76% Will!76% Will! Unsure 4% Not at all likely 4% Not very likely 16% Likely 28% Very likely 32% Extremely likely 16% Network World asked 500 readers to assess whether they would consider using voice over IP:
- 20. Key Business Drivers for LAN-Based Telephony and VoIP 81%81% 59%59% 38%38% 26%26% 0 50 100 Save MoneySave Money Better Utilization of BandwidthBetter Utilization of Bandwidth Support MultimediaSupport Multimedia Improve Network ManagementImprove Network Management
- 21. AsVoIP uses the Internet, for example, it is vulnerable to the same type as security risks Hacking Denial of service Eavesdropping CONCLUSION
- 22. REFERENCES
- 23. THANKYOU
Editor's Notes
- #19: MOS- Mean Opinion Score, a measure of voice quality score, each codecs has its own bandwidth requirements, VoIP normal delay is 100ms, so 3.5 is a good quality achievement