Telecom Testing
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Wireline
Wireless
(Broadband,SS7.....) (GSM,CDMA,Wi-Fi,3G,4G.......technologies)
* VOIP(SIP) Technology supports both Wireline and
Wireless.
VOIP(Voice Over Internet Protocol):
It is the internet technology to carry voice communication and multimedia sessions over Internet protocol networks such as internet.
The steps involved in originating voip telephone call are signalling and media channel setup,digitization of the analog voice signal, encoding ,packetization and Transmission as Internet protocol packets over a packet switched network.
Voip systems employ session control protocols to control the set-up and tear-down of calls.There are three types of Voip tools that are commonly used, IP phones, Softphone and Mobile Softphone.
- IP Phones: IP
Phones are the most institutionally established but still the
least obvious of the VOIP tools.
- Softphones: It’s
use has increased during the global recession as many persons, looking for
ways to cut costs have turned to these tools for free or inexpensive
calling or video conferencing applications.
Three classes of software IP: Web calling,voice and video instant messaging and
web conferencing.
- Mobile Softphone: It
is just another example of the adaptability of voip. Voip is available on
may smart phones and internet devices.
Voip has been implemented in various ways using both proprietary and
open protocols and standards.
PROTOCOLS:
Ø H.323
Ø Ip
multimedia subsysem (IMS)
Ø Media
Gateway Control Protocol (MGCP)
Ø Session
Initiation protocol (SIP)
Ø Real-Time
transport protocal (RTP)
Ø Session
Description Protocol (SDP)
The H.323 protocol was
one of the, first viop protocol that found wide spread implementation for
long-distance traffic as well as local area networks. Since development
of newer, less complex protocols , such as MGCP and SIP. The sip has gained wide
spread voip market penetration.
•
IETF Standard: Sip, Mgcp .
•
ITU Standard : H.323 ,Megaco .
•
Proprietory : IAX(Internation Asterix) , Sccp(Cisco) .
SIP and
H.323 are signalling protocols.
Mgcp and Megaco are
Media Gateway protocol
Voip Advantages:
1) Cheap calls or Free calls.
2) Low Equipment Cost .
3) Voice,Data,Video and
cable,Iptv.
4) Qos (Quality of
service).
Voip Dis-Advantages:
1) Bandwidth.
2) Electric Power
Voip Protocol Layers:
