2005-08-25 2026-01-12 Standards Action 0 DCCP-Request 1 DCCP-Response 2 DCCP-Data 3 DCCP-Ack 4 DCCP-DataAck 5 DCCP-CloseReq 6 DCCP-Close 7 DCCP-Reset 8 DCCP-Sync 9 DCCP-SyncAck 10 DCCP-Listen 11-13 Unassigned 14 Reserved for experimental and testing use 15 Unassigned 12-119 IETF Review (IETF RFC publication) 120-126 Reserved For experimental and testing use 127 IETF Review (IETF RFC publication) 128-255 CCID-specific codes 0 Unspecified 1 Closed 2 Aborted 3 No Connection 4 Packet Error 5 Option Error 6 Mandatory Error 7 Connection Refused 8 Bad Service Code 9 Too Busy 10 Bad Init Cookie 11 Aggression Penalty 12 Encapsulated Port Reuse 13 Abrupt MP termination 14-119 Unassigned 120-126 Reserved 127 Unassigned 128-255 CCID-specific codes 3-30 IETF Review (IETF RFC publication) 45-119 IETF Review (IETF RFC publication) 120-126 Reserved For experimental and testing use 127 IETF Review (IETF RFC publication) 128-255 CCID-specific codes 0 Padding 1 Mandatory 2 Slow Receiver 3-30 Unassigned 31 Reserved for experimental and testing use 32 Change L 33 Confirm L 34 Change R 35 Confirm R 36 Init Cookie 37 NDP Count 38 Ack Vector [Nonce 0] 39 Ack Vector [Nonce 1] 40 Data Dropped 41 Timestamp 42 Timestamp Echo 43 Elapsed Time 44 Data Checksum 45 Quick-Start Response 46 Multipath 47-119 Unassigned 120-126 Reserved 127 Unassigned 128-255 CCID-specific codes 10-119 IETF Review (IETF RFC publication) 120-126 Reserved For experimental and testing use 127 IETF Review (IETF RFC publication) 128-255 CCID-specific codes 0 Reserved 1 Congestion Control ID (CCID) 2 Allow Short Seqnos 3 Sequence Window 4 ECN Incapable 5 Ack Ratio 6 Send Ack Vector 7 Send NDP Count 8 Minimum Checksum Coverage 9 Check Data Checksum 10 Multipath Capable 11-119 Unassigned 120-126 Reserved 127 Unassigned 128-255 CCID-specific codes 0-1 IETF Review (IETF RFC publication) 4-247 IETF Review (IETF RFC publication) 248-254 Reserved For experimental and testing use 255 IETF Review (IETF RFC publication) 0-1 Unassigned 2 TCP-like Congestion Control 3 TFRC Congestion Control 4 TCP-Friendly Rate Control for Small Packets 5-247 Unassigned 248-254 Reserved 255 Unassigned Standards Action 0 Received 1 Received ECN Marked 2 Unassigned 3 Not Yet Received Standards Action 0 Protocol Constraints 1 Application Not Listening 2 Receive Buffer 3 Corrupt 4-6 Unassigned 7 Delivered Corrupt Service Codes can be found at the following: http://www.iana.org/assignments/service-codes RFC Required 0 0000 1-15 Unassigned RFC Required MP_OPT=0 MP_CONFIRM Confirm reception/processing of an MP_OPT option RFC9897, Section 3.2.1 MP_OPT=1 MP_JOIN Join subflow to an existing MP-DCCP connection RFC9897, Section 3.2.2 MP_OPT=2 MP_FAST_CLOSE Close an MP-DCCP connection unconditionally RFC9897, Section 3.2.3 MP_OPT=3 MP_KEY Exchange key material for MP_HMAC RFC9897, Section 3.2.4 MP_OPT=4 MP_SEQ Multipath sequence number RFC9897, Section 3.2.5 MP_OPT=5 MP_HMAC Hash-based message authentication code for MP-DCCP RFC9897, Section 3.2.6 MP_OPT=6 MP_RTT Transmit RTT values and calculation parameters RFC9897, Section 3.2.7 MP_OPT=7 MP_ADDADDR Advertise one or more additional addresses/ports RFC9897, Section 3.2.8 MP_OPT=8 MP_REMOVEADDR Remove one or more addresses/ports RFC9897, Section 3.2.9 MP_OPT=9 MP_PRIO Change subflow priority RFC9897, Section 3.2.10 MP_OPT=10 MP_CLOSE Close an MP-DCCP connection RFC9897, Section 3.2.11 MP_OPT=11 MP_EXP Experimental option for private use RFC9897, Section 3.2.12 MP_OPT=12-255 Unassigned RFC Required 0 Plain Text Plain text Key RFC9897, Section 3.2.4 1-254 Unassigned 255 Experimental For private use only RFC9897, Section 3.2.4 Note for CCID-specific codes: DCCP Reset Codes 128-255, Option Types 128-255, and Feature Numbers 128-255 are reserved for CCID-specific use. Each DCCP CCID (that is, each entry in the DCCP Congestion Control Identifiers registry) may create registries for its CCID-specific Reset Code, Option Type, and Feature Number ranges. These CCID-specific registries are independent: different CCIDs can allocate the same value (such as Feature Number 128) for different purposes. , Section 10.3, describes how DCCP decides which registry applies for a given CCID-specific Reset Code, Option Type, or Feature Number. In each case, CCID-specific registries may only register values 128-255; values 0-127 are registered here. For examples, see the following: http://www.iana.org/assignments/dccp-ccid2-parameters/dccp-ccid2-parameters.xhtml http://www.iana.org/assignments/dccp-ccid3-parameters/dccp-ccid3-parameters.xhtml http://www.iana.org/assignments/dccp-ccid4-parameters/dccp-ccid4-parameters.xhtml