Internet provides us with the wide range of abilities for watching videos and surfing the web, communicating by short messages, chatting at the social networks , working with email. However, few people know about the IP-telephony, with the help of which you can make voice calls for the low rates. so, how does the service works and how can it be connected?
Concepts of IP-telephony
It is one of the youngest types of communication. VoIP telephony, in fact appeared in 1999, after the development and approving of SIP-protocol (Session Initiation Protocol). The very functional protocol H.323 which was widely used at that time, and it is used nowadays, but rarely. It is very difficult, is not good enough, cannot provide the flexibility of the clients and not save the traffic.
SIP protocol is more flexible, simple and is more and more widely used at the IP-telephony for the office nowadays. It saves the traffic, provide an effective basis for work of different apps and devices. SIP protocol users can use virtual IP-telephony, moving free worldwide with saving personal SIP-ID. Special servers, which identify the location, provide such ability. To get more clear understanding of what is IP-telephony, we list abilities below:
- making voice calls;
- chatting by text messages;
- providing of transferring files and other multimedia information;
- connecting of the subscribers via videoconferencing;
- access to the online-games.
Telephony helps to connect the subscribers through the Internet, and the special gates provides an ability to make calls to the mobile and landline phone numbers.
There is another protocol— IAX2. It is not so open as SIP, but it saves traffic significantly. Also, IAX2 provide more clear and reliable VOIP-telephony, because data is transferred through the one port, not use several, as the SIP does. The difficulty of extension and deficiency of the resistance to cyber attacks (it is related to older versions) of this protocol.
How does IP-telephony work?
For better understanding of functional of the technology, let's review, how two VoIP-phones are connected. Devices are connected with servers of the specific provider and are connected to the Internet. When dialing the additional number of the other subscriber, servers identify its location and send the ring signal to it. The connection is established after the receiving of the call by the other subscriber.
In this case , it means That IP-telephony uses Internet to transfer a call and leaves the GSM channels free. Calls inside of the network is free of charge and subscribers, usually use free traffic.
The IP-telephony technology allows to make calls:
- between the users of one network (SIP-ID is used);
- between the subscribers of different networks with the applying of SIP URI (identificator that is similar to the email);
- from the VoIP-phones to the landline and mobile devices worldwide;
- from mobile and landline devices to the VoIP numbers.
Principle of the IP-telephony in the last two cases involves using of special gates, which are located at the specific countries and cities. This can give visible saving of funds, because at the most cases calls are made through the internet without using the traditional phone lines, that always are taking into consideration the distance between the subscribers.
Advantages of IP-telephony
Subscribers, that use this technology for the communication has an ability to connect real and virtual numbers (of different cities and countries) to the personal account, which allow to receive the incoming calls.
The advantage of internet-telephony is that subscribers can be located at any country worldwide, and the protocol, which is used let them communicate with a high level of flexibility. You can be online if the Internet connection is available.
Another advantage of IP-telephony is that tariffication for the subscriber does not change in such case, and on-network calling stay free. If the subscribers use the direct dial number, the location of them won't have an affect, whether they are neighboring offices or different places in the world. This is the flexibility of the users itself
The advantage of VoIP is also involved at absence of relation to the traditional phone lines, which allows to get a great saving. The absence of the common standard for the all SIP-apps could be referred to the disadvantages of IP-telephony. But, nowadays, the problem is solvable.
How to connect IP-telephony
The connection is realised in few steps. The very first step would be choosing the provider, which can grant the high-quality connection with the low rates. In order to connect IP-telephony, you need to have direct call number or ability to be reached by the additional number. Also, you are able to get other services, such as a second line, call holding and other.
After that, while building of IP-telephony network, you'll need to install SIP-app on your PC, which will be connected with servers, after making some settings. That will let you to receive and to send calls.
For receiving and sending calls you need to make settings at your own phone. To customize VoIP, you need to enter the parameters of the network at your PC or VoIP-phone. Make sure that ports, server addresses, password and login of your personal account are entered.
Provider informs its clients in detail, how to connect IP-telephony.
The main steps involve following:
- registration of account at the website of the provider;
- adding funds;
- phone setting;
- making test calls.
Entering personal account at the website of provider, you'll get the whole information about the soft settings, additional numbers, which you can give to your friends, relatives and colleagues to let them make calls to your IP-phone.