Fiber-microwave hybrid network | Cowlitz County Fire District #5

72018 March

Challenge

Cowlitz County Fire District #5 was relying on an older analog TDM based communications network for the links in their network where fiber was not an option. The paths were challenging from a terrain and obtaining rights angle. The costs to deploy fiber was too expensive. The original network design had made the best effort for network reliability and performance that would fit within the county’s budget. The county anticipated and budgeted for upgrading network equipment that was approaching end-of-life. The new equipment had to be IP based and optimized for network resiliency and reliability to Public Safety Grade standards for keeping the public safe. Another requirement was to have redundant microwave-backup to the fiber paths in the event of a failure and to prevent a potential “backhoe fade”. The county had recently obtained an engineering study for the system upgrade, but the recommended system was significantly more than what was available in the budget.

Solution

Cowlitz County Fire District #5 was searching for a qualified company to provide additional options for improving network reliability and redundancy that could be deployed within current budget levels. The chief was very familiar with the local ISP Cascade Networks dba/ Last Mile Gear (LMG). Based on their reputation for quality and affordability he asked Last Mile Gear for a recommendation. LMG engineered a 99.999% reliability – redundant microwave backbone system using SAF CFIP Lumina radios in a 1+1 configuration for the core network with Kenwood NXDN radios for the field public safety personnel. SAF radios were chosen because they provided the best cost to performance ratio compared to other microwave radios available in the marketplace.

The CFIP Lumina system provides:

- Full redundancy over Cowlitz Fire District #5’s paths where it was not feasible to deploy fiber
- Cost effective all-outdoor shelter free installation with low power consumption
- Industry-leading reliability and durability to withstand harsh environments
- Built-in managed Gigabit Ethernet switch for flexible network configuration
- High capacity IP traffic with ACM, ATCP, and QoS

Hybrid fiber-microwave network reliability

The wireless SAF Lumina network surrounds the Cowlitz Fire District #5 coverage area independent of commercial telecom providers. Lumina IP microwave links are also providing redundancy to the fiber paths in the network connect sites closing the loop creating a ring network topology. The protected fiber-microwave topology allows uninterrupted communications between fire safety personnel and other agencies in the event of an emergency. If a large fire or storm were to compromise a path in the network, communications are automatically rerouted through undamaged parts of the network. The SAF links backhauling the network are designed to 99.999% reliability exceeding the NPSTC recommended 99.995% availability specification. Each link is engineered with high fade margin to maintain connectivity during environmental events such as extraordinary wind, rain, snow, and ice. Each link is configured for “1+1 Hot Stand By (HSB)” providing redundant hardware with failover mechanisms at each point of failure. SAF radios are interoperable with the Cisco switches in the network which are also configured for “1+1” HSB. Each SAF radio is lifecycle tested before they leave the factory to ensure uninterrupted performance during extreme vibration, heat and cold environmental events.

“The network has been operational for over a year without a single disruption in service - dispatch call quality is crystal clear.” - Victor Leatzow, Cowlitz District #5 Chief

Public Safety

The overall goal is to provide the highest level of police, fire, and emergency medical services to the community. Preparation to handle major police and fire incidents is an important objective and a significant challenge to a small department like ours. Last Mile Gear designed the upgraded network to be compliant with practices recommended by the National Public Safety Telecommunications Council (NPSTC) for Public Safety Grade (PSG) Networks. The concept of PSG gives rise to network design choices that enable emergency responders to maintain communications during mission-critical incidents affecting life, health, and safety of the public. The network is designed to minimize the impact of, or eliminate entirely, equipment failures that result in a loss of data throughput or coverage and be designed in a manner that promotes the system’s quick return to optimal performance.

SAF provides the flexibility for future-proof networks capable of handling legacy analog voice traffic along with the most advanced IP applications demanded by today’s mission-critical public safety communications.

About customer

Cowlitz County is in the southwest corner of Washington and was inhabited for centuries by the Cowlitz Indians. These people were drawn to the region by the abundance of salmon. Cowlitz is the anglicized version of Cow-e-liske, meaning either “river of shifting sands” or “capturing the medicine spirit”. Cowlitz County Fire District #5 has been keeping people and property safe for more than a century. Their mission is to improve the quality of life of the community by progressively providing a highly trained, customer oriented emergency response service.

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Paul Koestner

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