Source: https://guthlabs.ai/docs/instruments/latency-bandwidth-transfer-time-calculator/implementation/

instrument implementation / implementation-contract

# Latency / Bandwidth / Transfer-Time Calculator implementation

A source-bound implementation contract for Latency / Bandwidth / Transfer-Time Calculator; deployment and executable qualification remain separate.

Status: **VERIFIED_CLEAN**Lifecycle: **implementation-contract**

## Binding contract

This record describes what an executable surface must bind and validate. It does not claim that a public calculator, package, or production route is deployed.

**Record owner**: Guth Instruments

**Lifecycle**: verified-clean

**Evidence ID**: t4-016

**Effect**: Computation or source lookup only

## Input and validation requirements

A zero-bandwidth input makes transfer time undefined and must be rejected explicitly. The unit-ambiguity vector also produces materially different results if GB/MB are interpreted as binary rather than SI prefixes, so the interface must enforce or display the selected convention.

## Required corrections

No binding erratum is attached to this unique-name record. Implementers must still preserve the declared units, domain, and failure behavior.

## Inspectable interface fixture

The sample below is evidence for interface and validation tests, not a production implementation.

````
{
  "inputs": {
    "file_size": 10,
    "file_size_unit": "MB",
    "bandwidth": 100,
    "bandwidth_unit": "Mbps",
    "RTT": 80,
    "RTT_unit": "ms",
    "TCP_window": 1,
    "TCP_window_unit": "MB"
  },
  "expected_outputs": {
    "transfer_time_s": 0.8,
    "BDP_bits": 8000000,
    "BDP_bytes": 1000000,
    "effective_throughput_bps": 100000000
  },
  "working": "10 MB = 10,000,000 bytes = 80,000,000 bits. Transfer time = 80,000,000 bits ÷ 100,000,000 bits/s = 0.8 s. RTT = 80 ms = 0.08 s. BDP = 100,000,000 bits/s × 0.08 s = 8,000,000 bits = 1,000,000 bytes. Window rate = 1,000,000 bytes ÷ 0.08 s = 12,500,000 bytes/s = 100,000,000 bits/s. Effective throughput = min(100,000,000, 100,000,000) = 100,000,000 bits/s."
}
````

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/latency-bandwidth-transfer-time-calculator/>)[02**Mechanism**](<https://guthlabs.ai/docs/instruments/latency-bandwidth-transfer-time-calculator/mechanism/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/latency-bandwidth-transfer-time-calculator/qualification/>)

## Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

- `VERIFIED_LEDGER.json`

- `evidence-tranche4/tranche4-results.json`