Transcript IAX Protocol

TEL500-Voice Communications
Session initiation protocol improvement using interasterisk 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)
Introduction cont.
 Codecs
Bandwidth Utilization over VoIP Networks
 Theoretical bandwidth calculation
 Comparison Practical bandwidth calculation
VOIP Protocols
 Centralized
 Distributed
• H.323
• SIP
• IAX
VOIP Architecture Models
SIP Protocol
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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
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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
 Codec 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:
BWn = BW x n x 2
Example : SIP using codec G.711
 CSI = 10ms
 CSS = 80 bytes
 VPS = 160 bytes
 BW30calls = 87.2 Kbps x 30 x 2 = 5232 Kbps
Calculation : Theoretical Value
BW Calculation Protocol SIP – codec G.711
Input data: CSI = 10 ms,
BW30calls = 87.2 Kbps x 30 x2 = 5232 Kbps (more than 5
CSS = 80 bytes, VPS = 160 bytes
Mbps)
BW Calculation Protocol SIP – GSM codec
Input data: CSI = 10 ms,
BW30calls = 36.4 Kbps x 30 x 2 =2184 Kbps (near 2
CSS = 80 bytes, VPS = 160 bytes
Mbps)
IAX Protocol – G.711 codec
Input data: CSI = 10 ms,
BW30calls = 84 Kbps + 65.6 Kbps x 29 =1986.4 Kbps
CSS = 80 bytes, VPS = 160 bytes,
(near 2 Mbps)
CBR = 64 Kbps, VPS (ms) = 20 ms,
PPS = 50
H.IAX Protocol – codec GSM
Input data: CSI = 20 ms,
BW30calls = 33.2 Kbps + 14.8 Kbps x 29 = 462.4 Kbps
CSS = 33 bytes, VPS = 33 bytes,
(Less than 512 kbps)
CBR = 13.2 Kbps, VPS (ms) = 20 ms,
PPS = 50
Practical Value
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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
• ^http://ofps.oreilly.com/titles/9781449332426/asteriskUnderstandingVoIP.html
•
^http://en.wikipedia.org/wiki/Category:VoIP_protocols
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^http://www.cisco.com/application/pdf/en/us/guest/tec
h/tk587/c1506/ccmigration_09186
a008012dd36.pdf
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Thank You
Any Questions Undergrad ???