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IPNetwork

IPNetwork

Telephone Network

Telephone Network

Broadcast Network

Broadcast Network

IPNetwork

IPNetwork

Storage Area

Network

Storage Area

Network

Voice Video Data Storage

Today’s Converged Networks© 2004 Cisco Systems, Inc. All rights reserved.Presentation_ID

Voice over IP (VoIP)

Traditional Call Centre Set Up

Call Centre Server

ACD/PBX

PSTN

Customer

CTI Interface

LAN

PBX Extensions

Agent StationsAgent Stations

ACD/PBX

What is VoIP?

VoIP let you make toll-free long distance voice and fax calls over existing IP data networks instead of public switched telephone network (PSTN).

VoIP solution can dramatically cut long distance call charges between two or more locations.

VoIP vs circuit networks

POTS (Plain Old Telephone Systems) used circuit switching techniques

Only 40-50% bandwidth used Cheaper cost Pay back period is short

Example of VoIP networks

PC (software) to PC (software) by home users

PC to phone Phone to Phone Inter Offices (across national/international)

Voice Traffic is Toll Free

VoIP services

Skype Vonage FreeWorldDialup Brekeke Yourself !

Equipment needed

An IP Network VoIP Server PC with VoIP software or VoIP phone VoIP adapter

VoIP protocols

Most popular VoIP protocols H.323 (http://openh323.org) SIP (http://www.sipforum.org/index.php)

Both support features like VoIP, Fax over IP and video conferencing

H.323 covers almost every service available but is harder to implement than SIP

ITU:H.323 Standard

Application Layer Protocol Binary based protocol Full detail of H.323 standard on

http://www.protocols.com/pbook/h323.htm

SIP Standard

SIP = Session Initiation Protocol Text based protocol, similar to HTTP Initiating interactive communication session

between users (voice, video, chat, interactive game and virtual reality)

SIP addressing

The SIP address is identified by a SIP URL, in the format: user@host.

Examples of SIP URLs: sip:hostname@vovida.org sip:m28@192.168.0.5 sip:294284@www.staffs.ac.uk

Useful SIP server and IP soft phone

SIP Server: OnDo SIP server Router with built-in VoIP features

IP soft phones: Windows Messenger 5.0 or higher SJPhone

References

http://wireless.ictp.trieste.it/school_2005/lectures/dillo/ICTP_VOIP_II.pdf

http://www.intel.com/network/csp/downloads/8983.htm

http://openh323.org http://www.sipforum.org/index.php http://www.skype.com