(VoIP)Is there a free analogue of Protei?

Question

linux

In telephony, I'm almost zero. It just so happened that our telephone operator quit, and now we are studying all sorts of E1s with the head of the department, etc. We use MKD Proteus as a VoIP server.
But I often see comments like that Aterisk does a lot more. And it's free. (for proteus we pay for TP).
Is there anyone here who has used both, and can anyone comment on the main disadvantages and advantages of one or another system?
At the moment, this proteus occupies our 3 hardware servers:
1) server
2) frontend
3) server replication
The number of subscribers on VoIP is about 1000.
Something bold somehow, it seems to me. Although I may be wrong.
I will be glad to any remark and suggestion.
Thanks in advance. Good evening everyone.

Answer 1

My advice to you, do not mess with an asterisk, especially with such a scale! Free does not mean that in this situation it is better to find someone who can manage to contain something similar to what you have now ... this is normal only a few will be able to. It is better to pay for the TP and return the telephone operator back in any way, this will come back to haunt you more than once, mark my words. In extreme cases, at least for the overprice, return him for a while and let him train his follower.

Answer 2

You will not hand over Asterisk to Rossvyaz and do not confirm SORM, do not play with billing. For now, better understand the rules for passing calls (local-area-intercity), joining other operators (technical conditions), softswitch classes, find your SBC.
The operator equipment does not require a lot of functionality. It just needs to work stably and bring in money. And in case of failure there was a third line of technical support.
To answer the question in the title, no. Equipment used in communication networks must be certified in accordance with Russian legislation. Nobody needs to certify open-source software.