SIP protocol killer Skype?
On Habré, many are campaigning for an open Jabber, instead of a closed ICQ. But at the same time, no one agitates for softphones based on the open SIP protocol, instead of any closed Skypes. But the essence of the matter is the same logic. Let's start?
First, about what SIP is and then why the killer. The SIP protocol is decrypted as the Session Initiation Protocol and serves to establish connections (sessions) between two computers. Consider a narrower task, such as a connection between two softphones. SIP protocol in this case is required in order to determine the location of clients (softphones), coordinate the parameters of audio transmission (codecs, bitrate), start the transmission and terminate it. There are still a number of parallel tasks, but for now we omit them for simplicity.
And so SIP is a protocol. For his work, you need to write some kind of program that will understand the language in which this protocol speaks. On the one hand, this is a server; on the client side, this is a softphone client. The benefit of such programs has already been written a lot, and it is not necessary to invent anything. What language does SIP protocol speak? On very simple. For example, in order to call the software, the background sends the following message to the SIP server:
INVITE sip: alice @ berkenson.com
Server is code:
180 - Ringing
200 - OK
As we see, the SIP URI of the form is used to identify users:
sip: alice @ berkenson.com
where to the right of the dog is the address of the SIP server, and to the left is the name of the user on it registered. Instead of a literal address, you can specify IP:
sip: alice@83.134.98.2
That is, by analogy with Jabber, you can raise your sip server yourself and keep everything under control, or register on any of the publicly available SIP servers (sipnet.ru for example).
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What happens when you want to call a friend?
1. You must be registered on any sip server. Suppose sip.ru (non-existent, find free Sip server in Google), and your login bob. Your sip address: bob@sip.ru
2. When you launch your softphone, you enter the registration data and contact your sip server. SIP server now knows your location (IP).
3. You call sip: alice @ berkenson.com. First, this address is sent to your SIP server sip.ru.
4. Your sip server using DNS will send a request to the Alice SIP server - berkenson.com.
5. SIP server berkenson.com finds out if there is such a user, is he online now, and his location (IP).
6. SIP servers find out which clients Alice and Bob use, and agree on the voice transfer parameters (codecs).
7. Softphones Alice and Bob know IP and the codec parameters of each other start data transfer using the RTP protocol (over IP). SIP servers are not involved in this process.
8. When someone hangs up, the information through the SIP server comes to another softphone and there are short beeps.
Everything is transparent and clear.
In fact, SIP is a protocol that manages the flow of voice, and with its help you can implement many additional functions - conferences, call forwarding, retention, etc.
Why is Skype's killer - because SIP is very serious, despite the simplicity, the protocol behind which the entire telecom industry stands. Buying a direct Moscow VoIP number you are 90% likely to buy a number that works on the SIP protocol and you can call it through your softphone. Is there such an option for Skype?
My forecast is that at first Skype will start to be preempted from corporate computers, as many are now switching to IP PBXs running on SIP'e, and then users will be pulled and simple.
Written on the eve of the launch of octopusline.ru
First, about what SIP is and then why the killer. The SIP protocol is decrypted as the Session Initiation Protocol and serves to establish connections (sessions) between two computers. Consider a narrower task, such as a connection between two softphones. SIP protocol in this case is required in order to determine the location of clients (softphones), coordinate the parameters of audio transmission (codecs, bitrate), start the transmission and terminate it. There are still a number of parallel tasks, but for now we omit them for simplicity.
And so SIP is a protocol. For his work, you need to write some kind of program that will understand the language in which this protocol speaks. On the one hand, this is a server; on the client side, this is a softphone client. The benefit of such programs has already been written a lot, and it is not necessary to invent anything. What language does SIP protocol speak? On very simple. For example, in order to call the software, the background sends the following message to the SIP server:
INVITE sip: alice @ berkenson.com
Server is code:
180 - Ringing
200 - OK
As we see, the SIP URI of the form is used to identify users:
sip: alice @ berkenson.com
where to the right of the dog is the address of the SIP server, and to the left is the name of the user on it registered. Instead of a literal address, you can specify IP:
sip: alice@83.134.98.2
That is, by analogy with Jabber, you can raise your sip server yourself and keep everything under control, or register on any of the publicly available SIP servers (sipnet.ru for example).
')
What happens when you want to call a friend?
1. You must be registered on any sip server. Suppose sip.ru (non-existent, find free Sip server in Google), and your login bob. Your sip address: bob@sip.ru
2. When you launch your softphone, you enter the registration data and contact your sip server. SIP server now knows your location (IP).
3. You call sip: alice @ berkenson.com. First, this address is sent to your SIP server sip.ru.
4. Your sip server using DNS will send a request to the Alice SIP server - berkenson.com.
5. SIP server berkenson.com finds out if there is such a user, is he online now, and his location (IP).
6. SIP servers find out which clients Alice and Bob use, and agree on the voice transfer parameters (codecs).
7. Softphones Alice and Bob know IP and the codec parameters of each other start data transfer using the RTP protocol (over IP). SIP servers are not involved in this process.
8. When someone hangs up, the information through the SIP server comes to another softphone and there are short beeps.
Everything is transparent and clear.
In fact, SIP is a protocol that manages the flow of voice, and with its help you can implement many additional functions - conferences, call forwarding, retention, etc.
Why is Skype's killer - because SIP is very serious, despite the simplicity, the protocol behind which the entire telecom industry stands. Buying a direct Moscow VoIP number you are 90% likely to buy a number that works on the SIP protocol and you can call it through your softphone. Is there such an option for Skype?
My forecast is that at first Skype will start to be preempted from corporate computers, as many are now switching to IP PBXs running on SIP'e, and then users will be pulled and simple.
Written on the eve of the launch of octopusline.ru
Source: https://habr.com/ru/post/28358/
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