VoIP Voice Over Internet Protocol
Advantages and Disadvantages
PSTN Public Switched Telephone Network
- It is known as landline telephone system.
- It was designed for purely analog voice communication by using wire network. It meant higher cost for long distance.
- Number of switches are involved to establish a connection.
- PSTN uses circuit switching. Dedicated path.
VoIP Voice Over IP
- Voice over Internet Protocol (VoIP) is a technology that allows users to make phone calls using internet.
- It is also known as IP telephony, Internet telephony or internet calling.
- The voice (and data) messages are split into packets by using digital signal processors (DSPs).
- VoIP uses packet switching. No dedicated path.
- Its is very cheap or Free. It uses the existing infrastructure of internet.
- A VoIP gateway (or PSTN Gateway) is a device which converts telephony traffic into IP for transmission over a data network.
- Perform DSP.
- Call Control.
- Bandwidth Management.
- Data Compression.
- Data Encoding.
Codec are of different types for data, voice, and Video. The quality and efficiency of the compression software has a big impact on the voice quality of VoIP traffic. There are good compression technologies and there are less good ones. Each compression technology is designed for a specific use under specific circumstances.
The signaling protocols govern the set-up and to many other related call management functions.
It is ITU-T standard protocol.It is actually a set of protocols .H.323 was designed for multimedia communication services such as real-time audio,video, and data communications over Ip Network.
SIP (Session Initiation Protocol).
It is IETF standard protocol and younger than H.323,it is lighter (requires less bandwidth). It is text-based. It is specially design for VoIP services.
SCCP (Skinny Client Control Protocol).
This is a proprietary CISCO signaling protocol used by CISCO products.