Educational program by sip. What is needed for IP telephony in the office?

Question

SIP

Good day everyone!
I’ll make a reservation right away, I haven’t encountered ip-telephony before, now there’s a task and I need to understand what’s what)
Please clarify, correct:
1. You can buy a sip number and a sip trunk from a provider. As the provider explained to me, a sip trunk is a separate channel, a "separate cable" for configuring telephony through it. That is, we connect this cable to a separate interface, and send all telephony requests there. It's right?
2. If so, then you buy a sip trunk, then you buy numbers, they work through this trunk, and the registration of these numbers on the provider's server is tied to the IP of the trunk? That is, it will not work to register from outside with this number, with these authorization data?
3. But at the same time, you can just buy a sip number and use it through a common Internet channel?
4. Asterisk, FreePBX will be installed. A trunk in asterisk terminology is a sip number? That is, you can add several numbers (trunks) to it, and already setting up routing, certain ext. numbers will call through the sip numbers we need.
5. If all of the above is correct, then when using the trunk from the provider, the server with the asterisk should have 2 network interfaces (local and trunk), or is port forwarding configured on the router from the asterisk to the trunk, from the trunk to the asterisk?
6. Using asterisk, is it possible to do without buying a sip trunk? buy only numbers.

Answer 1

Educational program by sip. What is needed for IP telephony in the office?

Brain)

Answer 2

brains need to love. as for the rest:
1. yes, only the channel may not be physical, but a separate VLAN, well, then the details. you understood the point.
2. you need a terminal client device - a telephone set (physical or soft) or an office PBX (physical or software) to catch a trunk on your side. If the provider allows you to register SIP subscribers via the Internet - from anywhere, even from Antarctica, register with the issued number.
3. see 2
4. A trunk is a trunk. Number is a number. A string of characters tied to your credentials (login and password will be given to you along with the number). You can at least write obscenities if you agree.
5. Absolutely right, port 5060 needs to come from the outside to your PBX or phone if you have one. This is for incoming connections so that they can call you.
6. You can, but you won’t go out to the city network without a provider and you won’t call your mobile phone. Inside, on the other hand, you can give out at least 10-digit numbers, an asterisk is a full-fledged automatic telephone exchange.
You need to read the instructions for the phone and study the logs from the proxy server. You didn't provide enough information to make a diagnosis.

Answer 3

1. You can buy a sip number and a sip trunk from a provider. As the provider explained to me, a sip trunk is a separate channel, a "separate cable" for configuring telephony through it. That is, we connect this cable to a separate interface, and send all telephony requests there. It's right?
2. If so, then you buy a sip trunk, then you buy numbers, they work through this trunk, and the registration of these numbers on the provider's server is tied to the IP of the trunk? That is, it will not work to register from outside with this number, with these authorization data?
3. But at the same time, you can just buy a sip number and use it through a common Internet channel?
4. Asterisk, FreePBX will be installed. A trunk in asterisk terminology is a sip number? That is, you can add several numbers (trunks) to it, and already setting up routing, certain ext. numbers will call through the sip numbers we need.
5. If all of the above is correct, then when using the trunk from the provider, the server with the asterisk should have 2 network interfaces (local and trunk), or is port forwarding configured on the router from the asterisk to the trunk, from the trunk to the asterisk?
6. Using asterisk, is it possible to do without buying a sip trunk? buy only numbers.
1. It is not necessary that you need a separate cable. You can receive a telephony service from any telecom operator (who provides VoIP), and set up this service on your PBX through any access to the Internet.
2. Registration is not always "bound" to IP. If you received a separate cable from a telephone operator, then yes, the service will be only within the cable. If you do as usual, like most, and set up your registration via the regular Internet, then it is not at all necessary that you will be tied to one IP. If you "lose" your username and password, then anyone from anywhere can connect and make calls on your behalf. It's like a password from the mail, roughly speaking.
3. Yes.
4. When you start setting up, you will understand. You are setting up a "trunk". And the number is given to you by the telecom operator. Further, you already "manage" numbers when setting up routing. Let's say, when setting up incoming routing, you specify which city number should be sent where (to the secretary, to the group of operators, to the voice menu, etc.). Outgoing, if you have more than 1 landline number, it can be both all calls from one external number, and each with his own. There are settings here.
5. No, you don't need two interfaces. Forwarding, in the case of NAT - is needed. 5060 and 10000-20000 - udp. It is highly desirable to restrict this forwarding with a firewall only for the IP address of your telecom operator.
6. You can. They just won't give you a number. Without trunk.
A special case, not uncommon - you buy a "trunk" from one operator without any numbers at all. And from another operator you buy only numbers, without a "trunk" at all. And you make a call to the "trunk" of one operator with the numbers of another.
This is especially common if, for example, you have changed your telecom operator, found it cheaper, but you don’t want to or cannot change the numbers. You make calls from one "trunk" (cheap) and receive calls to the old "trunk" from an expensive operator. Inbox is still free :)

Answer 4

some wild questions.
1. you can buy a number from one provider, and trunks from others. set up balancing on the PBX and if the trunk goes down, outgoing calls will continue to work. incoming go through the provider where the number is registered. sip trunk goes through the Internet. no extra cable needed.
2. registration on the trunk depends on the provider's security settings. you can set up a connection from one or more ip or just from the Internet.
3. yes. through the general Internet, it should work
4. I did not understand the question
5. my atska works while in LAN. mypbx phones connect to it via LAN, and it goes to the Internet through the LAN port. configured together with TP.
6 no. need a telephone connection. it is possible through a sim card, but this is a perversion
the provider should provide TP and help set everything up.
white IP is not needed
further advertising: www.octoline.ru PBX in the cloud. phones connect because of nat. no ports need to be forwarded. there are all kinds of nvr.