Registries Included Below
Standards Action or IESG Approval
Code points 0-7 MUST be supported an any implementation supporting UDP options. All others are supported at the discretion of each implementation.
| Kind | Length | Meaning | Reference |
|---|---|---|---|
| 0 | - | End of Options List (EOL) | [RFC-ietf-tsvwg-udp-options-45] |
| 1 | - | No operation (NOP) | [RFC-ietf-tsvwg-udp-options-45] |
| 2 | 6 | Additional payload checksum (APC) | [RFC-ietf-tsvwg-udp-options-45] |
| 3 | 10/12 | Fragmentation (FRAG) | [RFC-ietf-tsvwg-udp-options-45] |
| 4 | 4 | Maximum datagram size (MDS) | [RFC-ietf-tsvwg-udp-options-45] |
| 5 | 5 | Maximum reassembled datagram size (MRDS) | [RFC-ietf-tsvwg-udp-options-45] |
| 6 | 6 | Request (REQ) | [RFC-ietf-tsvwg-udp-options-45] |
| 7 | 6 | Response (RES) | [RFC-ietf-tsvwg-udp-options-45] |
| 8 | 10 | Timestamps (TIME) | [RFC-ietf-tsvwg-udp-options-45] |
| 9 | (varies) | Reserved for Authentication (AUTH) | [RFC-ietf-tsvwg-udp-options-45][draft-touch-tsvwg-udp-auth-opt-00] |
| 10-126 | (varies) | Unassigned | |
| 127 | (varies) | [RFC3692]-style experiments (EXP) | [RFC-ietf-tsvwg-udp-options-45] |
| 128-191 | Reserved | [RFC-ietf-tsvwg-udp-options-45] | |
| 192 | (varies) | Reserved for Compression (UCMP) | [RFC-ietf-tsvwg-udp-options-45] |
| 193 | (varies) | Reserved for Encryption (UENC) | [RFC-ietf-tsvwg-udp-options-45] |
| 194-253 | Unassigned - UNSAFE | ||
| 254 | (varies) | [RFC3692]-style experiments (UEXP) | [RFC-ietf-tsvwg-udp-options-45] |
| 255 | Reserved - UNSAFE | [RFC-ietf-tsvwg-udp-options-45] |
See [https://www.iana.org/assignments/tcp-parameters/tcp-parameters.xhtml#tcp-udp-exids].