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                                                             User Datagram Protocol (UDP)

   Created
   2025-03-25

   Last Updated
   2025-09-30

   Available Formats
   [IMG]
   XML [IMG]
   HTML [IMG]
   Plain text

   Registries Included Below

     ??UDP Option Kind Numbers
     ??TCP/UDP Experimental Option Experiment Identifiers (TCP/UDP ExIDs)

UDP Option Kind Numbers

   Registration Procedure(s)

 Standards Action or IESG Approval

   Reference
   [RFC-ietf-tsvwg-udp-options-45]

   Note

 Codepoints 0-7 MUST be supported on any implementation supporting
 UDP Options. All others are supported at the discretion of each
 implementation.


   Available Formats
   [IMG]
   CSV

    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       Timestamp (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 UNSAFE Compression (UCMP)    [RFC-ietf-tsvwg-udp-options-45]
   193     (varies) Reserved for UNSAFE Encryption (UENC)     [RFC-ietf-tsvwg-udp-options-45]
   194-253          Unassigned - UNSAFE
   254     (varies) [RFC3692]-style UNSAFE experiments (UEXP) [RFC-ietf-tsvwg-udp-options-45]
   255              Reserved - UNSAFE                         [RFC-ietf-tsvwg-udp-options-45]

TCP/UDP Experimental Option Experiment Identifiers (TCP/UDP ExIDs)

   Reference
   [RFC6994][RFC-ietf-tsvwg-udp-options-45]

   Note

 See [https://www.iana.org/assignments/tcp-parameters/tcp-parameters.xhtml#tcp-udp-exids].

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