Asterisk Open Source Phone Systems Jesse Rhoads LEAP-CF 03/19/2009

What is Asterisk? ➲ Open Source Phone System Software ➲ Claims to be the most popular FOSS project with over 2 million systems installed ➲ CLI-based. A Linux lover's dream! ➲ Back end engine with lots of customizing power. ➲ Revolutionary!

What can Asterisk Do? ➲ Route, Control, Manipulate Phone calls ➲ Sophisticated management interface API ➲ If you can script it, you can do it. Examples: Home Phone System: “Follow Me” Cooler things such as Home Automation Office Phone Systems: Unparalleled Flexibility Caveat: It's only free if your time is worthless!

System Requirements ➲ Bring your Lean, Mean, Linux Machine! ➲ Capacity Depends on Encoding needs. ● Various Codec Options for audio transfer ● Quality vs. Capacity (G711u/a vs G72x vs GSM) ● Get a motherboard that can handle IRQ's! ● 500MHz 64MB of RAM = 2 Calls ● 1 GHz 512 MB of RAM = 10+ Calls ● 2 GHz 1 GB of RAM = 30+ Calls ● Multi Core, More RAM, More Calls! ● Reserve 64kbps of bandwidth per call. ● QoS, QoS, QoS. Otherwise, packet loss!

Typical Installations ➲ Office Server, 100+ phones ● Hardware Trunking ● Where Public switched telephone network (PSTN) hard-wired access is a must. ● T1-PRI: 23 Line Channels or Multi-POTS w/ card ● Software Trunking to other Branches/Remote Offices ● Have an Analog Backup! ➲ Home Office, VOIP Only ● Uses VOIP Providers for all calls ● Software Trunking w/ Peers

PSTN Interface & Phones Hardware Device vs Software ➲ Use Hardware if mission critical (enterprise) ➲ Use Software if downtime is an option (home?) ➲ Best option is a hybrid blend with some... ● Redundancy!!! ➲ One call lost can translate to lost business. ➲ Spend the money. ● It's STILL CHEAPER THAN BUYING THAT PROPRIETARY SYSTEM THE EXECS WANT! ● Bells & Whistles are needed for WAF.

Common Obstacles to Asterisk & VOIP in General ➲ Echo due to duplex reverb ➲ SIP and RDP over NAT Translation ● The Protocol requires reverse mapping to IPs ● STUN (Simple Traversal of UDP through NAT) ➲ IAX (Intra-Asterisk Exchange) Trunking ➲ Echo ● Hello, is this thing on? ➲ Protocol conformance! ● Anyone who has done protocol programming knows what I am talking about.

VOIP Providers ➲ Pay As You Go vs. “Unlimited”* ➲ Vitelity ➲ Teliax ➲ VoicePulse ➲ BroadVoice ➲ Do your research! Read the forums. BBB. ➲ Proprietary: MagicJack, Vonage, Packet8, SunRocket, etc. ➲ * If you use a lot of minutes, be prepared to answer for them (pun intended)

Distributions ➲ Asterisk NOW! ● Digium's Attempt at a GUI ➲ SwitchVOX ● Complete Hardware/Software Solution ➲ TrixBox ● Started it all. FreePBX. Now a Fonality Product. ➲ Elastix ● FreePBX and all sorts of goodies! ➲ Grow your Own! ● Linux + Asterisk + Scripts = Very Win. ➲ Support + Hardware = Profit Model

Resources ➲ The VOIP Wiki! ➲ ➲ Asterisk: The Future of Telephony Book ➲ Forums on whirlpool.com.au ➲ Freepbx.org ➲ Trixbox.org ➲ Elastix.org ➲ Me!