User Datagram Protocol (UDP)
2025-03-25
2025-10-08
UDP Option Kind Numbers
Standards Action or IESG Approval
Codepoints 0-7 MUST be supported on any implementation supporting
UDP Options. All others are supported at the discretion of each
implementation.
0
-
End of Options List (EOL)
1
-
No Operation (NOP)
2
6
Additional Payload Checksum (APC)
3
10/12
Fragmentation (FRAG)
4
4
Maximum Datagram Size (MDS)
5
5
Maximum Reassembled Datagram Size (MRDS)
6
6
Request (REQ)
7
6
Response (RES)
8
10
Timestamp (TIME)
9
(varies)
RESERVED for Authentication (AUTH)
10-126
(varies)
Unassigned
127
(varies)
-style experiments (EXP)
128-191
Reserved
192
(varies)
Reserved for UNSAFE Compression (UCMP)
193
(varies)
Reserved for UNSAFE Encryption (UENC)
194-253
Unassigned - UNSAFE
254
(varies)
-style UNSAFE experiments (UEXP)
255
Reserved - UNSAFE
TCP/UDP Experimental Option Experiment Identifiers (TCP/UDP ExIDs)
See .