one of the founders of NetVoice
open source, Linux, and in particular Asterisk
also small telephone company
rack of Asterisk running at Bell Canada
"how I stopped worrying and learned to love the dialtone"
e164.org
- stations -- end points, aka a phone
- trunks -- tie you to another system
- PBX -- sit between stations and trunks
could all have a phone tied to Telus, but expensive, and don't have features -- transfers, voicemail, etc. etc.
- PBX == private branch exchange; this means you have a small telephone switch in your office, less trunks to the phone company
* FXO/FXS ports -- if you plug two phones into each other, nothing happens
* FXO port that you plug into the wall
* FXS is what you plug a station into (aka a phone)
* What is Asterisk? open source platform for telephony applications
* started in the US about 5 years ago by Mark Spencer
* vendor-neutral implementation -- works with lots of hardware
* lots of applications on top -- Asterisk works a bit like CGI-BIN, can communicate to other systems
* old fashioned way was to do processing directly on the hardware with DSPs; DSPs are expensive!
* as CPUs become more powerful, moved to processing directly on the processor, the interface port is nothing more than AD / DA converters, so they became much less expensive
* this breakthrough is what Asterisk exploited -- didn't need expensive hardware
* founder of Asterisk went to start a hardware company, Digium, which provided the now inexpensive hardware boards
* all successfull open source projects have had corporate sponsors like Digium to Asterisk; there are many other companies that provide the hardware boards
* scriptable telephony-to-anything
* MySQL connector
* your web app can make phone calls
- Alphabet soup of protocols
* IAX, not a real standard -- a common standard in wide use, for tying Asterisk systems together
* SIP, H.323, MGCP, MEGACO, SCCP - JINGLE!
* SIP is new
* H.323 was the original, designed by telephony-heads, it's going to die
* standards based, so commodity hardware
* e.g. Sippura, now bought by LinkSys, less than $100 for a gateway (small box, size of a deck of cards)
* another open source system, SIP Express Router
* not all features of Asterisk, only handles SIP
* very efficient, can handle 50K phones off a single CPU -- only handles call setup
* problem with SIP is that it puts IP address in packets -- this means that there are NAT issues
* ways to compensate, but NAT is still problematic
- system requirements for Asterisk
* 50 people, 23 trunks, 1 computer
* compression is what takes processing power
* Asterisk has strong ties to one company, Digium
* Digium has a heavey hand
- OpenPBX - fork of Asterisk
- Jingle - SIP, h.323, and Jingle all do signalling
* RTP actually does transfer
Boris Notes
- trixbox.org -- CentOS + Asterisk + flexible web admin tool
- tallk to Jonathan
- local Asterisk users group
