During this years’ Asterisk Developers’ Conference, one of the subjects I’ve raised an issue for Asterisk is: “Federating Multiple Asterisk Instances”. Now, for the seasoned Asterisk user/developer, the answer would be simple – use Kamailio/OpenSIPS for that scalability, and use Asterisk as a Media Gateway or application server.

But I ask the following: “What if we could federate Asterisk without the need for an external component? What if we could federate Asterisk in such a way where our users aren’t event aware of the federation process, and it’s fully autonomous? What would actually be required in order to do that?”

I’m normally confronted with these questions on a day to day basis, looking at the problem from different angles – thinking to myself: “Ok, I know the normal box here – but where are the outer limits? what can I do to make it more robust on one hand, without truly making a mess out of it.”

A federated database is defined as: “A federated database system is a type of meta-database management system (DBMS), which transparently maps multiple autonomous database systems into a single federated database. The constituent databases are interconnected via a computer network and may be geographically decentralized. Since the constituent database systems remain autonomous, a federated database system is a contrastable alternative to the (sometimes daunting) task of merging several disparate databases. A federated database, or virtual database, is a composite of all constituent databases in a federated database system. There is no actual data integration in the constituent disparate databases as a result of data federation.” – http://en.wikipedia.org/wiki/Federated_database_system

So, we would like to virtually create a “map-reduce” functionality for Asterisk? can we truly create a map-reduce’ish functionality for Asterisk? should it be internal? should it be external?

In order to accomplish this, we are required to create a federator – a device capable of handling the information regarding each users, device, trunk, provider and other wise SIP/IAX2 entity connected to our system. The federator for all practical purposes is a data store, be it a key-value store, a database, a shared memory environment or some other form of data distribution layer.

Here are some key issues that true federation may be required to tackle:

1. Geo-Position Agnostic – A truly federated system should render services identically across the board, regardless of where the user is located.
2. Services Agnostic – A truly federated system doesn’t care if the user is connected to an Asterisk server version 12 or 13, it should behave identically.
3. Version Agnostic – A truly federated infrastructure can leverage older version and even other software, without changing the underlying federation layer.
4. Predictable Scalability – A truly federated infrastructure will allow for growth to be planned linearly, with discrete measure methods.

So, you want a tip on how to start federating your systems? here’s step number 1 – there is no central registry, there is no SIP proxy, there is only the cloud and the services it renders. Start thinking from this point and see where you go.