[VoiceOps] VoiceOps Digest, Vol 82, Issue 18

Alex Balashov abalashov at evaristesys.com
Tue Apr 19 19:56:05 EDT 2016

On 04/19/2016 07:51 PM, Jared Ball wrote:

> Does using Kamailio and the dispatcher module require programming?  Is
> this a matter of reading the documentation and some configuration or
> does this involve writing a script for handling any SIP dialogue that
> might come my way?  I want to implement this in 3 - 6 months.  I don't
> want to embark on an 18 month research endeavor.

Kamailio does have the problem of being relatively low-level. It can 
almost be thought of as a kind of SDK with a SIP proxy service core, and 
its behaviour is configured with a domain-specific language that 
corresponds to the SIP transactional state machine. It's not declarative 
and doesn't do much of anything useful out of the box.

So, yes, it requires some programming, and yes, your route script needs 
to be reasonably comprehensive in the SIP scenarios it can handle.

Having said that, you don't need an eighteen-month research endeavour to 
implement a load balancer using the dispatcher module, even as a novice:

- The stock configuration that's packaged with Kamailio goes a long way 
toward providing "minimally viable handling" for all canonical SIP 
scenarios (e.g. loose-routed in-dialog requests, and even NAT traversal) 
if you lean toward modifying a stock config.

- There's lots of examples online about how to implement a load balancer 
with dispatcher, since it's done so commonly.

- You can get help on the mailing list. The community is very helpful:


- You can always hire a consultant to do this for you. A basic load 
balancer using dispatcher is not a big or expensive job.


-- Alex

Alex Balashov | Principal | Evariste Systems LLC
1447 Peachtree Street NE, Suite 700
Atlanta, GA 30309
United States

Tel: +1-800-250-5920 (toll-free) / +1-678-954-0671 (direct)
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