Description
Decode the top two option-type bits as action and bit five as mutable.
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.
Decode the top two option-type bits as action and bit five as mutable.
When to use this tool
Use IPv6 Option Action Bits when you need to decode or encode one explicit packet field.
How to use the tool and how it works
- Enter optionType. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read action, mutable, actionToken. Inspect mutable before interpreting the associated values.
Decode the top two option-type bits as action and bit five as mutable. Return the action token from the fixed skip/discard/ICMP policy table.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| optionType | Option Type | Required. Safe integer; minimum 0; maximum 255. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| action | Action | Required. Safe integer. |
| mutable | Mutable | Required. Boolean. |
| actionToken | Action Token | Required. Text; maximum UTF-16 length 8192. |
{
"input": {
"optionType": 194
},
"output": {
"action": 3,
"mutable": false,
"actionToken": "discard-send-icmp-unless-multicast"
}
}Limitations and assumptions
- This labels encoded instructions; it does not decide whether an actual node should send ICMP in a particular context.
- 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
- IPv6 Routeralert Option Value Field
Join high and low octets in network order.
- DHCP Option Length Octet Field
Require a code from 1 through 254 and a length byte from 0 through 255; return the two-byte header.