Description
Multiply the 16-bit window by 2 raised to shift, with shift from 0 through 14.
TCP advertises a receive window in a 16-bit field. A negotiated scale expands its interpretation for one direction, while SYN segments use the unscaled field.
Multiply the 16-bit window by 2 raised to shift, with shift from 0 through 14.
When to use this tool
Use TCP Window Scaling One Direction when you need a window capacity under an explicit scaling convention.
How to use the tool and how it works
- Enter window, shift, syn. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read effectiveBytes. Use the output convention below.
Multiply the 16-bit window by 2 raised to shift, with shift from 0 through 14. When syn is true, use exponent zero.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| window | Window | Required. Safe integer; minimum 0; maximum 65535. |
| shift | Shift | Required. Safe integer; minimum 0; maximum 14. |
| syn | Syn | Required. Boolean. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| effectiveBytes | Effective Bytes | Required. Finite number. |
{
"input": {
"window": 1000,
"shift": 4,
"syn": false
},
"output": {
"effectiveBytes": 16000
}
}Limitations and assumptions
- Use the negotiated scale for this direction; negotiation and segment classification are caller responsibilities.
- Inputs must satisfy both the field types and the cross-field conditions above. Invalid input causes an error; a successful false flag or documented placeholder is a different result.
- Numeric calculations use binary floating point unless exact decimal-integer arithmetic is explicitly stated. No hidden measurement tolerance or decimal rounding is added; nonfinite or out-of-contract results are rejected. Numeric signed-zero results are exported as zero.
Alternative or Complementary methods
Inspect both handshake directions to establish the negotiated shift before interpreting later window fields.
References
Similar or alternative tools
- TCP Window Scale Effective Capacity
Multiply window by 2 raised to shift, except that synSegment selects an unscaled window.
- TCP Sequence Syn Fin Consumption
Add payloadBytes and one sequence position for each true SYN and FIN flag.