Description
Classify field values at most 1500 as length, at least 1536 as etherType, and the intervening values as reserved.
Packet headers encode several meanings in fixed-width fields. Bit positions, network byte order, and reserved values must be distinguished from validation of an entire message.
Classify field values at most 1500 as length, at least 1536 as etherType, and the intervening values as reserved.
When to use this tool
Use Ethernet Type Length Branch when you need to decode or encode one explicit packet field.
How to use the tool and how it works
- Enter field. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read branch. Use the output convention below.
Classify field values at most 1500 as length, at least 1536 as etherType, and the intervening values as reserved.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| field | Field | Required. Safe integer; minimum 0; maximum 65535. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| branch | Branch | Required. Text; maximum UTF-16 length 8192. |
{
"input": {
"field": 1500
},
"output": {
"branch": "length"
}
}Limitations and assumptions
- An etherType classification does not identify a protocol or verify frame size.
- 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 the complete captured header and apply the relevant protocol's structural and state rules.
References
Similar or alternative tools
- Network: Ethernet Ethertype Hex Label
Format field as 0x plus four hexadecimal digits.
- Ethernet Padding Payload Shortfall
Use a header of 14 + 4 × vlanTags bytes for zero through two tags.