Open Source Softswitch Adds Skype

Here's an interesting teaser for you Skype aficionados. Later this month, the new release of FreeSWITCH, the first open source softswitch, will enable carriers and enterprise to integrate Skype into their VoIP services and platform.

For the first time, developers will have a free, high-performance voice switching platform that can tie Skype clients into nearly every other major VoIP platform on the market today. Aside from extending high definition voice across networks, FreeSWITCH 1.04 will enable developers to build Skype integration into telephony applications, such as VoIP-enabled IVRs.

Skype enhancements aren't the only changes in store for FreeSWITCH. The open source community has also added support for one of the most popular telephone engines, the Open Phone Abstraction Layer (OPAL), which gives FreeSWITCH support for H.323 clients and devices. OPAL also brings another venue for SIP support, which FreeSWITCH already provided.

Advanced telephony services are also now available through FreeSWICH's Event Socket (ESL) specification. ESL allows software to control FreeSWITCH through a scripting language. Calls connect to a daemon to provide IVR services. In this way, one can build a distributed application that offloads processes from FreeSWITCH server or connect legacy applications into the FreeSWITCH network.

If there's a challenge that developers will encounter with FreeSWITCH's new Skype chumminess it's likely to be in the number of Skype sessions that can be handled at one tim. The Skype endpoint module works as a virtual sound card, playing the voice which is then re-encoded by the FreeSWITCH server and delivered to the recipient. As such, the Skype implementation should carry a fair amount of overhead. Scalability has yet to be fully tested. According to Anthony Minessale, the creator of FreeSWITCH, preliminary testing has shown scalability of up to only 20 Skype clients. Additional scalability is expected with larger systems.

The other question to consider is Skype's own work in opening up the Skype client. The Skype API is now in beta that will allow developers to decompose the Skype client into elements for incorporation into their own software. The API is expected to be publicly available next year.

Skype is also working towards tighter integration with platforms. The Skype for Asterisk is a prototype for such native interaction and allows for interoperability between Skype and Asterisk.  As such, it should offer better voice quality, allow for user to place and receive calls without any cumbersome workarounds, provide caller ID, and other features, such as retrieving Skype credit balance information.

At the same time, Asterisk lacks FreeSWITCH's scalability, which makes it better suited for application development and carrier implementations than Asterisk. Native interaction though isn't available yet for FreeSWITCH, but purportedly is in the works. Until that happens, FreeSWITCH Skype functionality will likely be second to its open-source rival, Asterisk.