Citywide Voice and Video Using Asterisk and Open-Source
Embedded Hardware
Kelvin ChuaChief Technology Officer NEXTix Inc.Astricon 2009
Taguig City, PhilippinesHigh monthly recurring telecommunication costs
Legacy EOL PABX
Non-resilient single point of failure
Flexibility issues
No contact-center features
No cdr reports and call statistics
No centralized dial plan
Highly dependent on PSTN infrastructure
Project AdvantagesVirtually unlimited phone lines/numbers
Centralized communications
24/7 Inquiry and emergency hotline service
Security and reliability
Scalability and Extensibility
Faster deployment
Ease of operation
Project Design and Implications
Less interconnection with the PSTN
Network and application layer redundancy
QOS on all data nodes
Remote site contact-center integrated
Network monitoring system
Disaster resiliency
And most importantly, least cost :)
Network Diagram
Project Implementation: Data Network
Choice of technology: 802.16e WiMax
Multiple Star Topology
QOS on both the client and central nodes
VLAN tagging across the wired and wireless network
Project Implementation: Telephone Network
Initially 2 ISDN PRI from 2 different providers as the
main PSTN interface and an ITSP link via SIP
2 Digium 24port for interim connectivity to legacy PABX
A minimal number of landlines were maintained for
redundancy in far-flung areas. These are connected to
embedded asterisk-based appliance.
Project Implementation: Asterisk Servers
4 Asterisk servers in 2 physical locations
Clustered dialplan (primary and secondary proxy)
Fax dispatch system based on hylafax and iaxmodem
Autoprovisioning
Mysql backend
Support for SIP video endpoints and video conferencing
Project Implementation: Embedded Appliances
Based on Blackfin DSPs
Fanless, Solid-state open-hardware design
Supports FXO, FXS and PRI
Embedded firmware with GUI
Clustered dialplan
Project Implementation: Network Monitoring System
Based on Cacti open-source graphing solution
SIP/IAX peers online/offline as well as concurrent
SIP/IAX/Dahdi(Zap) calls
System voicemail
Heartbeat and threads
SNMP
Automated triggers and alerts
Project In Action:
Sudden ease in remote inter-department calls
Unauthorized toll calls were eliminated
Government services became more efficient
All incoming calls, including death threats, extortion
and corruption activities are now monitored
Cost savings on monthly recurring telecom charges
Proven disaster survivability
September 26, 2009 at the height of tropical storm “Ketsana”. Asterisk saved a lot of
casualties, serving thousands of calls a day for the city government's contact center.
Thank You!
For more info:
http://www.nextixsystems.com
http://www.nextixsystems.com/citywide-telephony.php
http://www.nextixsystems.com/citywidefactsheet.pdf