1. Voice Over Internet Protocol (VoIP)

2. Basic Components of a Telephony Network

3. Central Office Switches Classes of CO Switches Class 5: (C5) -End office Switches Class 4: (C4) -Tandem Switches C5’s are considered the higher layer switches at the core of the switching network. C4’s are more local switches and closer to the CO.

4. Analog-to-Digital Voice Encoding

5. Compression Bandwidth Requirements

6. Supervisory Signaling

7. Basic Call Setup

8. What Is a PBX?

9. Packetized Telephony Networks

10. Packet-Switched Telephony vs. Circuit-Switched Telephony More efficient use of bandwidth and equipment Lower transmission costs Consolidate network expenses Increased revenue from new services Service innovation

11. Distributed Call Control

12. Centralized Call Control

13. Packet Telephony Components

14. Real-Time vs. Best-Effort Traffic Real-time traffic needs guaranteed delay and timing. IP networks are best-effort with no guarantees of delivery, delay, or timing. The Solution is end-to-end quality of service (QOS).

15. T1 Interface A US T1 with 1.54MB of bandwidth and 24-channels, can handle 23 voice calls at 64kbps each. One of the channels is dedicated for Data or T1 control. In comparison, a US T3 with 45MB of bandwidth can handle 672 voice calls at 64kbps each.

16. Today’s PSTN So why can’t our current PSTN handle the emergence of VoiP, video, and data services all on the same circuits of the original PSTN network? =Because, you can’t run a converged network on what is primarily a network that was designed for just VOICE. Many US carriers and private companies have large data buildings just to ride VOICE traffic over a data network. Equation  VOICE + VIDEO + DATA OVER A DATA NETWORK= CONVERGENCE

17. Requirements of Voice in an IP Internetwork

18. IP Internetwork IP is a connectionless protocol IP provides multiple paths from source to destination

19. Packet Loss, Delay, and Jitter Packet loss  Loss of packets severely degrades the voice application. Delay  VoIP typically tolerates delays up to 150 ms before the quality of the call degrades. Jitter  Instantaneous buffer use causes delay variation in the same voice stream.

20. Reordering of Packets IP assumes packet-ordering problems will occur RTP reorders packets into their original form A c B

21. Reliability and Availability Traditional telephony networks claim 99.999% uptime. Data networks must consider reliability and availability requirements when incorporating voice. Methods to improve reliability and availability include:  - Redundant hardware  - Redundant links  - UPS Power Systems  - Proactive network management/monitoring

22. Major VoIP Protocols

23. VoIP Protocols and the OSI Model