What is SIP?

What is SIP?

It is created in such a way so the SIP telephony clients can use UDP and TCP port 5060 to connect to the SIP servers and other SIP endpoints. The main purpose of SIP is to set up and tear down video or voice calls. In cases where initiation of the session is required, however, SIP is being used as well. Events Subscription, event notification and Terminal mobility are included there. Many SIP related RFCs in reality define the behavior for this solutions. All video/voice communications are made over separated session protocols, similar to RTP.

SIPs main task is to provide a call setup and signaling protocol or IP communications, which support a mega set of the call processing features and functions available in the PSTN (Public Switched Telephone Network). The protocol itself, is defining the focus of signaling and the call setup. Nevertheless it was designed to be able to initiate a building of featured elements of network called User Agents and Proxy Servers. Basically, those features that allow making traditional telephone operations: ringing, dialing, hearing busy signals or ring tones.

SIP powered telephone networks also implement many advanced features of call processing available in SS7 (Signaling System 7), however those two protocols are different. SIP is a P2P (peer to peer) protocol, with very complex architecture and dumb endpoints of central network; due to this it requires really simple core network with distributed intelligence to the network edge. SIP features are used comparing to traditional SS7 ones, which are implemented in the network.

SIP is described as if it has IP roots, rather than traditional telephone industry, but other VoIP signaling protocols exist. The H.323 VoIP protocol is traditionally more relevant to the ITU, SIP has governed and standardized by the IETF. Those two companies endorsed the protocols in fashion.

SIP is similar to HTTP and shares its principles as well. "404 not found" codes, structured request response can be found in both protocols. However SIP is simpler than H.323. Although some do counter that, of course SIP has an aim to be simple, but at its current state it is as complex as H.323.


VoIP Newest WIKI - SIP
sip protocol
SIP protocol was made within IETF (Internet Engineering Task Force) – organization occupied with establishing Internet standards and general standards concerning TCP/IP protocols. 
SIP Addresses and telephones
SIP-addressing is logical, of the same type as URL in HTTP. And the most natural – to use the electronic mail as the SIP address. There are permissible varied parameters by the address: for example, it is possible to indicate the regular city telephone number, additional telephone, and the parameters of modem connection etc.
SIP Communications of real time
Obviously SIP is considerably better than H.323 and complies with the understanding of IP-telephony as a global mass IP-service, and it should be implicitly considered right this way. And as SIP is able to serve not only telephony but also any communications at all in the real time over the IP-protocol; obviously it should become a base for other IP-services not yet existing but will appear in the future, as well.
SIP Telephony
A modern voice communication SIP protocol is widely used to make calls in the Internet. However, the final subscriber is mostly interested not in the very SIP standard but in the SIP telephony conception based on it. One one hand, all traditional conveniences for making telephone calls, compatibility with the international subscription base and the procedure of dialing numbers are kept.
SIP VoIP Phones
Depiction of ‘’Locktek WP04 WiFi IP SIP Phone The Locktek WP04 WiFi IP SIP phone is a huge single boost in mobile communications. The device weights about 3oz, has a crystal clear color TFT (Thin Film Transistor) display and keeps standby mode up to 140 hour with a factual time on line at 7.5 hours spare. This SIP phone offers along with dimming screen and keypad feature, characteristics, that never were reached before by all previous SIP hardware, in sense of operational and stand by time. Phone has multi-dialing pad, when you can dial regular phone numbers, IP addresses and SIP accounts in a straight forward way. Two or more customers, handling two or variety WP04 SIP phones on local intranet, just can dial the IP of another WP04 device to get connection, in this case SIP account is not required to be involved.

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