TEL500-Voice Communications Session initiation protocol improvement using inter- asterisk exchange Devesh Mendiratta & Sameer Deshmukh MS-Telecommunication State University of New York Institute of Technology

Introduction  VOIP Network  VOIP Protocols SIP ( Session initiation protocol) IAX ( inter-asterisk exchange Protocol)

 Codecs  Bandwidth Utilization over VoIP Networks  Theoretical bandwidth calculation  Comparison Practical bandwidth calculation Introduction cont.

VOIP Protocols  Centralized  Distributed H.323 SIP IAX

VOIP Architecture Models

SIP Protocol  Session Layer Protocol  “Request and Response” Mechanism  Sessions & Video data between two endpoints  File types & formats  After establishing a session – responsibility of average flow transfer is delegated to RTP i.e. Transport layer  Dynamically allocation of port (10000 to 20000)

IAX Protocol  Session layer protocol  Provides control & VoIP networks  Point-to-point  Media & signaling protocol  Multiplexing of signaling  UDP port 4569  Trunked IAX

Codecs  Analog voice is converted to a digital signal  Then it is carried across the Internet.  Examples based on compression level G.711 G.726 G.729A GSM iLBC Speex MP3

Calculation : Theoretical Value  Cod ec bit rate = (codec sample size)/(codec sample interval)  Packets per seconds = (codec bit rate)/(voice payload size)  Total packet size = L2 + IP + UDP + L5 + voice payload size  The BW required for n conversations full duplex: BW n = BW x n x 2

 CSI = 10ms  CSS = 80 bytes  VPS = 160 bytes  BW 30calls = 87.2 Kbps x 30 x 2 = 5232 Kbps Example : SIP using codec G.711

Calculation : Theoretical Value BW Calculation Protocol SIP – codec G.711 Input data: CSI = 10 ms, CSS = 80 bytes, VPS = 160 bytes BW30calls = 87.2 Kbps x 30 x2 = 5232 Kbps (more than 5 Mbps) BW Calculation Protocol SIP – GSM codec Input data: CSI = 10 ms, CSS = 80 bytes, VPS = 160 bytes BW30calls = 36.4 Kbps x 30 x 2 =2184 Kbps (near 2 Mbps) IAX Protocol – G.711 codec Input data: CSI = 10 ms, CSS = 80 bytes, VPS = 160 bytes, CBR = 64 Kbps, VPS (ms) = 20 ms, PPS = 50 BW30calls = 84 Kbps Kbps x 29 = Kbps (near 2 Mbps) H.IAX Protocol – codec GSM Input data: CSI = 20 ms, CSS = 33 bytes, VPS = 33 bytes, CBR = 13.2 Kbps, VPS (ms) = 20 ms, PPS = 50 BW30calls = 33.2 Kbps Kbps x 29 = Kbps (Less than 512 kbps)

Practical Value  Vyatta installation  Configuring interfaces & static routs on Vyatta  Installing CentOS 5.2 OS on servers Asterisk 1 & 2  Installing Asterisk PBX on servers 1 & 2  Installing Wireshark & Unsniff sniffer on the machine  SIP & IAX extensions settings  Dial plan configuration

BW SIP, G.711, 30 CALLS

BW SIP, GSM, 30 CALLS

Comparison Table

Conclusion  SIP & G.711 codec => very good quality of voice highest consumption of BW  IAX & GSM codec => lowest consumption of BW high traffic – distortion  IAX & G.711 codec => ideal for power traffic level is relatively high requires high bandwidth  SIP & GSM codec => ideal for plans that do not support IAX

Resources ^ UnderstandingVoIP.html ^ ^ h/tk587/c1506/ccmigration_09186 a008012dd36.pdf

? Thank You Any Questions Undergrad ???