IP Phone
IP Phone
IP phone is a specialized device that comes in two types, the first type is a hardware based IP phone which is very much like normal phones but with more features that may support voice and video and the second type is a software based IP phone which is installed on your computer system and it is very similar to the hardware in terms of look and functionality.
- Hardware based IP phone
- Software based IP phone
IP phone connected to the network with RJ-45 connector, it may receive power over the network cable (power over Ethernet) or it can have a standard power supply. IP phones receive IP (internet protocol) to send and receive voice traffic.
The IP phone uses a signaling protocol to build, monitor, control and terminate phone calls. These signaling protocols are,
1. SIP _ the Session Initiation Protocol is the Internet Engineering Task force standard and it is the mostly used protocol on the internet for voice, video and text communication.
2. H.323 _ is an International Telecommunications Union Telecommunication Standardization Sector (ITU-I)
3. SCCP is the Skinny Client Control Protocol _ Cisco proprietary; it is a lightweight protocol that is built on client server model.
4. MGCP _ Media Gateway Control Protocol is a client-server protocol built on centralized control architecture.
Where the actual voice traffic transition from the Caller to the Celle is passed through the Internet protocol infrastructure is carried over RTP.
1. RTP _ Real time Transport Protocol is the protocol used to carry voice and video media traffic with all the other signaling protocols “SIP, H.323, SCCP, MGCP”
2. RTCP _ provides statistics and control information for the RTP media traffic
Asterisk Protocol: IAX is the Inter-Asterisk eXchange _ open source Asterisk protocol that carries both signaling and media on the same port
The IP phones consist of elements such as,
- DNS client
- NAT traversal client
- DHCP client
- Signaling stack
- RTP and RTCP Stack
- Codec (Audio codec and Video codec)
