0cpm: Open Source Firmware for SIP telephony

Rick van Rein, OpenFortress

Abstract

The SIP protocol holds great promises for our future of telephony; not only comprises it a plethora of media formats to exchange, but also peer-to-peer connectivity over the bare Internet, and signalling advances like only bothering a party in line with their presence setting and waiting until presence settings of a number of parties allow for a conference call. Nothing of this is being achieved in current-day practice.

A serious issue with SIP is that it is too complex to configure for most end users, due to a dependency on IPv4 and NAT routers. If we leave it to the existing providers of infrastructure and phones, there may not be IPv6-based SIP telephony until everyone can switch.

To break through this impasse, we are working on 0pcm, which is open source firmware for SIP phones. The 0pcm group intentionally makes a clean break with the older style of SIP telephony, which seems concerned only with simulation of analog telephony. The time is ripe to define a new level of best practices: IPv6, ZRTP, ENUM, ITAD and much more.

Rather than offering IPv4 service with IPv6, 0pcm takes the angle of IPv6-only with a fallback to a suitable tunneling mechanism where needed. Using such phones and existing SIP dialing techniques such as ITAD and ENUM, it finally becomes possible to call freely. Free as in free beer and, much more importantly, free as in free speech.

Rick hopes to be able to demonstrate the 0pcm firmware during this talk. Either way, he will explain how the firmware can be applied to existing hardware that was designed for various VoIP protocols, including SIP over IPv4.

http://devel.0cpm.org

Bio

Through OpenFortress, Rick van Rein builds infrastructural solutions that usually are of an innovative nature. Being a cryptographer, he usually tries to incorporate security and privacy in a way that is easily accessible to end users.