Resilience Tier Rating

Rating sites resiliance against various types of failures.
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Will your node serve the network when it is needed most?

TODO: This entire concept is a work in progress by Casey KV3T. Your feedback is encourages and appreciated.

Concept

The resilience tier rating (RTR), is an objective systems of ratings to determine which nodes are most likely to continue to serve the network during various types of outages or failures. It is a system of 10 key metrics, which can be objectively evaluated, to determine how reliable a node is during adverse conditions. These factors can be summed to determine a final RTR, which can be used to quickly evaluate relative resilience.

This concept is inspired by the FEMA ICS resource categorization concept. Where resources are rated type I, II, III or IV depending on its capabilities. Each category class has objective metrics used to rate functionality in a given situation. This allows a single simple language to used throughout the entire incident command system. Its consistency allows for Note that higher is not always better. Some factors apply more or less to various use cases. A portable node with a 500AH battery backup is impractical. A client tunnel connection only serves its purpose if it has an internet connection. Therefore its entire use case relies on the internet and is not resilient against internet outages by design. This is not a single metric that will rate all client nodes, it is simply a tool that can be used when evaluating link connections. Additionally, the concept can be utilized via a simple math equation to calculate a link resilience tier rating (LRTR), or the rating of your link connection reliance from node A to node B.

This concept is to help others understand the relative resilience of each network component, and encourage members to increase the resilience of their deployed assets for the betterment of the network in the face of adverse operating conditions.

Metrics

Hardware Suitability

Memory

  • 63MB or less: 0 pts
  • 64MB or more: 5 pts

MIMO

  • no: 0 pts
  • yes: 5 pts

Mounting Suitability

This rating assumes the unit is mounted outside. If it is mounted inside, it receives a rating of 0. If unit is exterior rated, it receives a rating of 5.

If the mounting point is secured against sustained winds in excess of 100mph, an additional 5 points is awarded.

Power Resilience

How resilient is the node against power abnormalities.

If not battery backup is supplied, it receives a rating of 0.

If the node is on generator backup use figures below for how long the generator will run without human intervention (IE, how much gas is in the tank connected to the generator, not how much is on site.) If the generator will reboot gen-start subtract 2. If a combination generator and battery is used, use the combined length of how long the node will stay up without human intervention.

  • 1 day of power backup: 3 points
  • 3 days of power backup: 5 points
  • 7 days of power backup: 6 points
  • indefinite power backup (solar, wind, hydro): 10 points

Network Resilience

How resilient is the nodes network connection.

  • If the node is not RF connected, it receives a resilience score of 0.

  • Average S/N Ratio: If the average link connection between this node and its link into the network (or other backbone nodes) is between:

    • 0-15: 0 pts
    • 15-20: 1 pts
    • 20-30: 3 pts
    • 30-40: 5 pts

    • 50: 10 pts

Accessibility

  • How accessible is the node?
    • Unknown or unreliable access: 0 pts
    • Accessible with prior scheduling, required notice more than a day in advance: 1 pts
    • Easily accessible within four hours notice, access controlled by others: 3 pts
    • Easily accessible by the control with certain time frames (IE, 9am to 5pm Monday through Friday, gate is locked dusk to dawn, etc): 5 pts
    • Easily accessible by the control operator. If need, the site could be accessed at any time, with no prior schedule or approval. Control operator “has the key”: 10 pts

Total Score

The current maximum possible score is 50. Add up the scores, and divide by 50 to get your nodes RTR rating.

Park Tower

As a reference, this is how park tower is calculated.

  • Hardware
    • 128MB: 5 pts
    • MIMO YES: 5 pts
  • Power
    • 1 day of battery backup (estimated): 3 points
  • Network Resilience
    • 20 to 30: 3 pts
  • Accessibility
    • prior scheduling required days in advance: 1 pts

17 out of 50: 34%