jon "maddog" hall: open telephony

Copyright Linux International 2009

Open Telephony: Freedom Greater Than A Sum Of Its Parts

ByJon “maddog” HallLinux International

Just For Fun

http://www.youtube.com/watch?v=WGjzm6hzXaA

Needed For Telephony: Then

Needed For Telephony Later...

The “Telephone Company”

● Not a total monopoly....but almost● They owned everything

– The phones– The telephone lines– The switching equipment– The long distance lines– The employees– You

Along The Way:Trouble In River City

And Even More Trouble

And Lots Of Trouble

Choice....

....but no control● Choose long distance carrier● Choose handset● Choose cellphone carrier● Choose PBX supplier

but you could not open any box

Then One Day.......SIP Happens!

● VoIP!● Talking over the Internet!

● IP – already digital, packet switched network

● VoIP – transform voice to digital packets and transmit them via IP

● Quality of Service (QoS)– packet

● loss● delay● re-transmission

Types of VoIP

● Direct– Hardware VoIP phone to other VoIP device– Software VoIP phone to other VoIP device

● Indirect– VoIP device to PBX “server”

● PBX provides services and/or converts to POTS

And More Phones Appeared...

But They Were Still Closed

There Were A Few Softphones

Even Some Of Them Were Closed....

What Is WRONG With “Closed”?

● Supplier goes out of business● Supplier “loses interest”

– Retires product line– Merges products

● Bug fxes - “Its really a computer”!● Upgrades● Migrating data from one phone to

another

Choice, But Only Their Choices

● Upgrading hardware may mean software change

● May have to pay for ISP you do not use● Limited number of plans● No real freedom

● Large companies used lots of telephone lines to CO– 10 to 1 rule

● 2000 employees, 200 talking on phone

– lots of calls inside business

● Switchboard “CO” inside of business– Few lines to outside

Services

● Digital switching ofered services– Voice mail– Caller ID– Call forwarding– etc.

● Ofered by CO – Centrex● Ofered by in-house PBX

All of this is POTS – Plain Old Telephone Service

Dialing Plan

“Please Dial 9.....”

For a Long Time:Closed, Proprietary, EXPENSIVE

Then, A Major Step Forward!

Open PBX:Asterisk

● Open Source Software– Runs on Linux, BSD, etc.– Allows better integration to company

software

● Support of diferent hardware interfaces (T1, E1, FXO/FXS, more)

Open PBX:Asterisk (Cont.)

● PBX (including long distance Gateway)

● Call Parking/Forwarding/Waiting, etc.

● Music to hold by

● Voicemail Services with Directory

● Conferencing Server

● Packet Voice Server

● Encryption of Telephone of Fax Calls

● Custom Interactive Voice Response

● Number Translation

● VoIP with diferent protocols (H.323, SIP, IAX, etc.)

Scenarios

● “Free” portals to other countries● Saving money calling from other

countries● One customer, ten salespeople● Blending of Telephony and “rest of IT”

Advantages: Not Just Saving Money

● Avoid “Fork Lift Upgrades”● Better integration to rest of systems

Mexico City

“Senior Hall, I have done it!”

Open Source As Solutions:Additional Advantages

● Less reliance on one vendor● Less reliance on ANY vendor● Distributed risk

– low cost allows more redundancy

● Lower cost hardware● Standard hardware

Intermixing of Technologies

● Now it is all “IP”– Audio– Video– Metadata

● Mixing “data” and “control”

What if we did not use telephony to bring communications.....

Intermixing of Technologies

● Now it is all “IP”– Audio– Video– Metadata

● Mixing “data” and “control”

What if we did not use telephony to bring communications.....

..what if the phone was really a computer?

What If The Handset Was Really Open?

What Does It Mean For Hardware To Be “Open”?

● Published APIs to the hardware● Published CAD drawings for case● Published schematics and component

layout for the Printed Circuit Board● Open development forums

Control = Choice

● Choice of operating system– Qt Extended– OpenMoko (OM)– Debian– Android– Others

● Choice of transmission– GSM– WiFi

Control (Cont.)

● Choice of Carrier● Choice of ISP● Choice of Services● Choice of Support● Choice of PBX services● Choice of when to upgrade● Future choice of handset designs

Beware “Partially Open”

● Does the software have to be “signed”?● Is the carrier “locked”?● Unlock the phone?

– Will you get updates?– Will you get security patches?

● Does the vendor limit the applications?– Remove WiFi clients?– Remove other applications?– Not publish all the source code?

Sometimes...

“It is better to be completely closed than partially open...”

- Jon “maddog” Hall, 1995

Control

From Handset to Datacenter

Sources Of Information:Companies

● Digium - www.digium.com● Openmoko - www.openmoko.org● Koolu - www.koolu.com● Videos - http://www.youtube.com/user/openkoolu

Questions?

http://www.youtube.com/watch?v=9dVch2nSuBA

jon "maddog" hall: open telephony

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