Asterisk capacity

Hi all,

I would like to understand Asterisk capacity / dimensioning limits from the architectural prospective.

Imagine that you have theoretically unlimited hardware resources on your server.
In this case, what is the capacity limit of a single Asterisk node - in terms of the number of endpoints and / or concurrent calls?
Let’s assume the following:

  • only SIP or PJSIP channel driver is enabled
  • only basic functionality (i.e. 2-way calls) is used.
  • up-to-date Asterisk version (13 or 15) is installed.

Of course, in the real life you will never get an infinite hardware capacity.
However, there should be a boundary where it will make more sense to set up a second node connected to the first one via trunk - rather than upgrade the only server.

Do you have any practical examples of running large Asterisk systems on a single node? How large are they?

Thank you.

This is a really hard question to answer. There’s nothing in Asterisk itself, like fixed array sizes, that limits the number of calls or endpoints that it can support. You could run into operating system/protocol limits though like file handles/sockets, ports, etc. that aren’t tied to hardware capacity. Of course you also could run into bandwidth limits.

The question you really have to ask yourself is “What happens if that one server goes down?”. Even if the hardware is perfect, you’ll have to upgrade software at some point. How much of an outage can you tolerate?