VOICE OVER INTRENET PROTOCOL
BCA 6th SEM JNVU
VoIP stands for Voice over Internet protocol
“ VoIP is the ability to make telephone calls over
IP-based data networks with a suitable
quality of service and superior cost . ”
Also known as
Voice over Broadband
VoIP Technology emerged over Public switched Telephone
• The first VoIP software was introduced in 1995 by
Designed for home PC
Uses H.323 Protocol
Uses Packet Switching
PC to PC.
Phone to Phone Via Internet.
Phone to internet to PSTN.
PSTN to Internet to PSTN.
PC to PC
Need a PC with sound card
IP Telephony software(softphone):
Skype, Gtalk, VoIP Stunt....
Phone to Phone
Need more gateways that connect IP network to phone
Networks, Internet, The carrier switches
The IP network could be dedicated intra-net or the
PC to Phone
Need a gateway that connects IP network to
SIP (Session Initiation Protocol): The SIP protocol is a
standard developed by the Internet Engineering Task Force
(IETF) for establishing multimedia sessions such as voice,
instant messaging and video
IAX(Inter Asterisk eXchane): The IAX protocol was
developed by a team of open-source developers working on
the Asterisk project
H.323: The call setup protocol H.323 is standardized
by the International Telecommunications Union (ITU).
In a VoIP environment, H.323 is a common protocol
running on voice gateways to connect the VoIP network
to the PSTN.
IMS(IP Multimedia Subsystem): IMS is currently in
development and testing phases, and was originally
developed as a protocol for carrying 3G telephony data.
Applications of VoIP
• Real time applications:
Telephony ( two-way)
Radio-TV Broadcast (one-way)
• Non-real time applications:
Integration of data, voice and fax
Used in Amateur Radio
Advantage of VoIP
Integration of Voice and Data
Free IP to IP
Disadvantage of VoIP
Phone line is down if broadband connection is down
Phone router occasionally must be rebooted
Voice quality degrades if internet connection has latency, jitter
of significant packet loss.