Traffic Routing Calculator

Split traffic across weighted origin pools and see the blended latency, plus what happens when a pool drops out.

About Traffic Routing Calculator

Weighted routing normalises against the sum of healthy weights, so ejecting a pool silently redistributes its share to the survivors in proportion to their own weights rather than evenly. Blended latency is the weighted mean, which is why sending even 10% of traffic to a distant pool moves the average far less than it moves that 10% of users. The blended number is what your dashboard shows and the per-pool number is what those users feel, so weighted routing can look healthy while a tenth of your traffic is served twice as slowly — and the failure case shows what happens when the nearest pool is the one that drops.

Formula

Traffic Routing

pool share = pool weight ÷ sum of healthy weights; blended latency = Σ(weight × pool latency) ÷ sum of healthy weights, with unhealthy weights removed before normalising.

healthy weights: Weights of pools currently passing their health check
blended latency: Weight-averaged latency across the pools actually in rotation
latency penalty: Increase in blended latency once the best pool is removed

Worked example

With the default values below, Traffic Routing Calculator returns Blended Latency of 60.00. Change any input above and every figure here is recalculated in your browser.

Inputs used

Requests per monthaccepts 0–10,000,000 million: 500 million
Pool A weightaccepts 0–1,000 weight: 60 weight
Pool B weightaccepts 0–1,000 weight: 30 weight
Pool C weightaccepts 0–1,000 weight: 10 weight
Pool A latencyaccepts 0–60,000 ms: 45 ms
Pool B latencyaccepts 0–60,000 ms: 70 ms
Pool C latencyaccepts 0–60,000 ms: 120 ms
Pool healthone of All three pools healthy, Pool C unhealthy, Only pool A healthy: All three pools healthy

Results

Blended Latency: 60.00 ms
Pool A Share: 60.0%
Pool B Share: 30.0%
Pool C Share: 10.0%
Requests to Pool A: 300.00 million
Requests to Pool B: 150.00 million
Blended Latency Without Pool A: 82.50 ms
Latency Penalty if Pool A Is Lost: 22.50 ms

Step by step

1Values used
2Traffic Routing
3Blended Latency= 60.00 ms
4Pool A Share= 60.0
5Pool B Share= 30.0
6Pool C Share= 10.0
7Requests to Pool A= 300.00 million
8Requests to Pool B= 150.00 million

Assumptions and limits

The result is derived only from the 8 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

How is Traffic Routing calculated?

pool share = pool weight ÷ sum of healthy weights; blended latency = Σ(weight × pool latency) ÷ sum of healthy weights, with unhealthy weights removed before normalising. Weighted routing normalises against the sum of healthy weights, so ejecting a pool silently redistributes its share to the survivors in proportion to their own weights rather than evenly. Blended latency is the weighted mean, which is why sending even 10% of traffic to a distant pool moves the average far less than it moves that 10% of users.

Why does Traffic Routing matter?

The blended number is what your dashboard shows and the per-pool number is what those users feel, so weighted routing can look healthy while a tenth of your traffic is served twice as slowly — and the failure case shows what happens when the nearest pool is the one that drops.

What values do I need to enter?

This calculator takes 8 inputs: Requests per month, Pool A weight, Pool B weight, Pool C weight, Pool A latency, Pool B latency, Pool C latency, Pool health. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.