Voice Over IP (VoIP)

Boyapati, Roopesh Understanding VoIP ConceptsComponentsFunctionalityProtocolsChallengesDemo

Boyapati, Roopesh Why VoIP? EconomyMobility Local Numbers

Boyapati, Roopesh VoIP Overview

Boyapati, Roopesh ATA (analog telephone adapter) Provides Dial tone Provides Ring Signal for incoming calls Analog to Digital conversion (Outgoing calls) Digital to Analog (Incoming calls) 2 Types

Boyapati, Roopesh CODEC Audio Signal Conversion G.711: 64000/ second G.729A: 8000/ second

Boyapati, Roopesh Soft Switches Call Processor Phone number associated with that end point End point’s current IP address Specialized database/ mapping program.

Boyapati, Roopesh Calling Process Pick Receiver, this sends signal to ATA ATA checks n/w connectivity and sends dial tone Dial Phone Number Phone number sent to VoIP service providers call processor Soft switch connects both ends Signal sent to receiver’s ATA to ring

Boyapati, Roopesh Protocols H.323 Session Initiation Protocol RTPRTCP

Boyapati, Roopesh H323 Developed by ITU Uses signaling messages

Boyapati, Roopesh SIP Defined by RFC 3261 Application Layer Protocol Used to initiate, maintain and terminate sessions Independent of underlying transport protocol

Boyapati, Roopesh RTP Real Time Transport Protocol By IETF, 1996 Works with all signaling protocols Operates at transport layer Independent of transport protocols used Transports real time data

Boyapati, Roopesh RTP (contd.) Contains incrementing sequence number in each packet Contains a sync source identifier and a time stamp

Boyapati, Roopesh Real Time Control Protocol Works hand in hand with RTP RTP does data delivery while RTCP sends control packets Ensure QoS to sender Reports percentage of packet loss and jitter

Boyapati, Roopesh DEMO

Challenges Available bandwidth Delay/Network Latency Packet loss JitterEchoSecurityReliability Pulse dialing to DTMF translation Emergency 911 Calls

Boyapati, Roopesh References

Boyapati, Roopesh Thank You !