The Challenge
911 emergency services represent the most critical communications infrastructure in any community. When someone calls 911, the system must work. There is no acceptable failure mode. For the Fairbanks area, this meant designing and deploying a Next-Generation 911 Emergency Services IP Network (ESInet) that could survive any single failure while meeting the unique latency and reliability requirements of emergency voice communications.
My Role
I served as principal architect and project engineer for the deployment of a fully redundant E911 ESInet supporting both primary and backup Public Safety Answering Point (PSAP) locations in Fairbanks, Alaska.
Architecture Design
- Designed end-to-end network topology with zero single points of failure
- Specified redundant transport paths using diverse physical infrastructure
- Engineered multicast network design for VoIP requirements specific to 911 operations
- Developed failover mechanisms ensuring seamless PSAP operations during any component failure
Hybrid Transport Design
- Designed primary connectivity over dedicated fiber optic infrastructure
- Engineered backup paths using microwave radio links
- Ensured physical path diversity between primary and backup transport
- Calculated link budgets and fade margins for Alaska’s challenging RF environment
VoIP/Multicast Engineering
E911 systems have unique networking requirements that differ significantly from standard enterprise VoIP:
- Designed multicast networking supporting efficient voice distribution
- Engineered quality of service policies ensuring voice priority
- Specified network timing and synchronization for voice quality
- Implemented monitoring and alarming for proactive issue detection
Implementation
- Managed network equipment deployment at PSAP locations
- Coordinated with microwave equipment vendors on tower installations
- Oversaw fiber optic construction and termination
- Conducted comprehensive acceptance testing before cutover
Technical Architecture
Redundancy Philosophy
Every component of the system was designed with redundancy:
- Transport: Independent fiber and microwave paths with automatic failover
- Network Equipment: Redundant switches and routers at each location
- Power: UPS and generator backup at all critical sites
- Monitoring: Redundant NMS with out-of-band management access
Microwave Backup
The microwave radio backup links were engineered to stringent availability requirements:
- Path diversity from fiber routes
- Fade margin calculations for Alaska’s precipitation and atmospheric conditions
- Automatic protection switching for seamless failover
- Hot standby radios eliminating single points of failure
Results
The deployed ESInet successfully provides redundant connectivity for 911 services in the Fairbanks area. The architecture has proven its resilience through multiple fiber cuts and equipment failures, automatically failing over without impact to emergency call handling.
When someone in Fairbanks calls 911, the network I designed ensures that call gets through. Every time.