Description
Split the identifier and sequence 16-bit words into high and low octets, returning four bytes in that order.
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.
Split the identifier and sequence 16-bit words into high and low octets, returning four bytes in that order.
When to use this tool
Use ICMP Identifier Sequence Word Split when you need to decode or encode one explicit packet field.
How to use the tool and how it works
- Enter identifier, sequence. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read bytes. Use the output convention below.
Split the identifier and sequence 16-bit words into high and low octets, returning four bytes in that order.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| identifier | Identifier | Required. Safe integer; minimum 0; maximum 65535. |
| sequence | Sequence | Required. Safe integer; minimum 0; maximum 65535. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| bytes | Bytes | Required. Array of safe integer; maximum items 256. |
{
"input": {
"identifier": 4660,
"sequence": 43981
},
"output": {
"bytes": [
18,
52,
171,
205
]
}
}Limitations and assumptions
- This serializes two fields only; it does not construct a complete ICMP message.
- 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
- ICMP Type Code Composite Token
Join type and code as type × 256 + code and format their octets as four lowercase hexadecimal digits.
- IPv4 Header Checksum Word Contribution
Combine high and low octets as high × 256 + low to obtain a 16-bit network-order word.