Asterisk VoIP News

Wednesday, October 19, 2005

Announce: New ISDN architecture available for Asterisk

Matteo Brancaleon has posted on the List with details of a new ISDN protocol.


A new ISDN architecture, called vISDN, has been developed to fully support EuroISDN protocol with HFC based cards: HFC-S PCI, HFC-4S and HFC-8S (with HFC-E1 and HFC-S USB support coming soon).

vISDN is not based on Zaptel, libpri, chan_zap, zaphfc, qozap, etc... but has been designed from scratch to be a standard compliant EuroISDN implementation plus a channel crossconnector, plus protocol analysis support thru Ethereal, plus a ppp terminator, plus other stuff :)

Main Features:
- Open, modular, flexible and versatile architecture
- Fully GPLed
- Full support for PRI and BRI
- Full support for Network and Terminal Equipment role
- Traffic analysis with (patched) Ethereal
- E-channel sniffing
- D-channel sharing between applications (in TE-multipoint mode)
- Good integration with latest 2.6 kernels and extensive usage of their newer features (e.g.: sysfs)
- Protocol stacks are implemented following the finite-state-machine models described in the ETSI specification for better compliance/debuggability.
- Termination of PPP connections without exiting from the kernel
- Takes advantage from HFC's framer for HDLC traffic
- Preliminary/experimental support for hardware PCM bus
- Preliminary support for hardware channel bridging
- Support for dynamic (optionally automatic) activation/deactivation of layer2 (DLC connection)
- Unintrusive with respect to the Linux kernel and Asterisk (no patches needed)

Missing Features:
- Echo cancellation (likely going in in the next release)
- Explicit Call Transfer

Please note: This is a Linux-only, 2.6-only architecture which supports only EuroISDN. It is currently in beta-stage, brave testers will be more than welcome; people who want to contribute will be welcome too. You will not need to sign a disclaimer to participate but you will receive good and valuable consideration, plus discrete amounts of beer :^)

vISDN will undergo a layer2/layer3 certification by an independent lab and will have a "Declaration of conformance" valid in the EU territory. AFAIK, the declaration is valid for the product as a whole, so, it is to be seen if the declaration could be extended to "mixed" products.

Please see for further information. If you are near Milan Italy, vISDN is live at SMAU expo. We will be happy to show the driver working live and exchange comments and ideas about it(Voismart - hall 12 booth H22)