Also, Kamailio's procedural route script language is a major asset of its particular methodology.
While it can sometimes be a pain for newbies trying to do relatively simple, canonical kind of things, the flexibility it affords in scripting SIP outcomes on a very granular level, and providing a powerful state machine within that programmatic framework, are both hugely important to "non-trivial" endeavours.
The feature set of something like an Acme Packet NetNet SD is essentially static; it does what it does, and not one bit more. It may have a lot of capabilities, but those capabilities are all a matter of configuration, not of customisation or extension. It is in something like Kamailio (or Asterisk or Freeswitch) that you can truly *extend* the functionality, allow it to interface with other open-source and proprietary components, build complex middleware and business layers, etc.
On 08/31/2012 08:13 AM, Alex Balashov wrote:
Commercial SBCs are quite featureful, but their feature set is extremely static, and often depends on vendor consulting and expertise to be approachable.
Nobody claimed the open-source solutions are simple to support or don't require expertise. They're not free, either, as everyone well knows.
In my view, the real value of something like Kamailio - where it's not merely a money-saving measure but can achieve truly spectacular multiplier effects in technological leverage - is in its integration paths (MI and sercmd/binrpc), HTTP client/server, database connectors, integrated servers, etc. The ability to develop new kinds of applications and services that rely on making disparate components talk to and interoperate with each other in novel ways, as well as to make better, more economical use of existing technology through those same kinds of facilities, is where the real power truly lies. Some commercial products powered by proprietary stacks have APIs too, but they're light years behind the open-source world in this regard; they are far too bureaucratic and inflexible.
This is where our customers typically see massive payback of using something like Kamailio, aside from the any savings on licensing costs (both of the core network element and potential dependencies).