Protocol Registries

Protocol parameter registries represent the authoritative record of many of the codes and numbers contained in a variety of Internet protocols. We maintain these records in compliance with the associated technical standards and allocation policies, and we provide this service in coordination with the Internet Engineering Task Force (IETF).

To view or download individual protocol registries, navigate to the individual registries through the index below. Registry data is available for bulk retrieval via Rsync (recommended) or FTP.

To obtain a registration in an existing registry, or to modify existing registrations, consult the relevant application form. For information on creating new registries, please see RFC 8126 for guidance.

Protocol/Registry	Defining Document/Comments
Access Node Control Protocol (ANCP)
ANCP Capability Types RFC 6320 Standards Action
ANCP Command Codes RFC 6320 Standards Action
ANCP Message Types RFC 6320 Standards Action
ANCP Port Management Functions RFC 6320 Standards Action
ANCP Result Codes RFC 6320 0x0-0xFFF: IETF Review. 0x1000-0xFFFFFF: Specification Required.
ANCP Technology Types RFC 6320 Expert Review
ANCP TLV Types RFC 6320 0x0000-0x1FFF: IETF Review. 0x2000-0xFFFF: Specification Required.
Joint GSMP / ANCP Version Registry RFC 6320 Standards Action
ACL TLS
ACL (D)TLS Parameters RFC 9761 Expert Review Dan Wing Per Andersson
ACL DTLS Version Codes RFC 9761 Expert Review Dan Wing Per Andersson
ACL TLS Version Codes RFC 9761 Expert Review Dan Wing Per Andersson
Ad Hoc On Demand Distance Vector (AODV) Parameters
AODV Extension Types RFC 3561 Standards Action
AODV Message Types (for messages sent to port 654) RFC 3561 Standards Action
Address Family Numbers
Address Family Numbers RFC 2453, RFC 2677, RFC 2858 1-16383: Standards Action. 16384-32767: First Come First Served.
Address Resolution Protocol (ARP) Parameters
Hardware Types RFC 826, RFC 5494 requests for values below 256: Expert Review. requests for more than one value: Expert Review. requests for one value greater than 255: First Come First Served. requests for one value, no value specified: First Come First Served. Carlos Pignataro
Operation Codes RFC 826, RFC 5494 IETF Review or IESG Approval
Protocol Type RFC 826, RFC 5494, RFC 5342 The Ethertype space is administered as described in [RFC5342].
APEX Parameters
Applicable Exchange Core (APEX) Endpoint Applications RFC 3340 Expert Review
Applicable Exchange Core (APEX) Options RFC 3340 Expert Review
Applicable Exchange Core (APEX) Services RFC 3340 Expert Review
Application Access Protocol (ACAP) Numbers
ACAP Capabilities RFC 2244 Specification Required
ACAP Response Codes RFC 2244 First Come First Served
Dataset Classes RFC 2244 Standards Action or IESG-Approved Experimental RFC
Vendor Subtrees RFC 2244, RFC 6075 First Come First Served
Application Bridging for Federated Access Beyond Web (ABFAB) Parameters
ABFAB URN Parameters RFC 7833 IETF Review or Expert Review
Application-Layer Traffic Optimization (ALTO) Protocol
ALTO Address Types RFC 7285 IETF Review
ALTO Cost Metrics RFC 7285 IETF Review
ALTO Cost Modes RFC 9274 IETF Review
ALTO Cost Source Types RFC 9439 IETF Review
ALTO Endpoint Property Types RFC 7285 IETF Review
ALTO Entity Domain Types RFC 9240 IETF Review
ALTO Entity Property Types RFC 9240 IETF Review
ALTO Error Codes RFC 7285 IETF Review
Authenticated Encryption with Associated Data (AEAD) Parameters
AEAD Algorithms RFC 5116 1-32767: Specification Required. 32768-65535: Private Use. David McGrew Bjoern Tackmann Stanislav Smyshlyaev
Authentication and Authorization for Constrained Environments (ACE)
ACE Authorization Server Request Creation Hints RFC 9200 less than -65536: Private Use. -65536 to -257: Specification Required. -256 to 255: Standards Action. 256 to 65535: Specification Required. greater than 65535: Expert Review. Göran Selander
ACE Groupcomm Errors RFC 9594 less than -65536: Private Use. -65536 to -257: Specification Required. -256 to 255: Standards Action With Expert Review. 256 to 65535: Specification Required. greater than 65535: Expert Review. Francesca Palombini Marco Tiloca Rikard Höglund
ACE Groupcomm Key Types RFC 9594 less than -65536: Private Use. -65536 to -257: Specification Required. -256 to 255: Standards Action With Expert Review. 256 to 65535: Specification Required. greater than 65535: Expert Review. Strings of length 1: Standards Action With Expert Review. Strings of length 2: Specification Required. Strings of length greater than 2: Expert Review. Francesca Palombini Marco Tiloca Rikard Höglund
ACE Groupcomm Parameters RFC 9594 less than -65536: Private Use. -65536 to -257: Specification Required. -256 to 255: Standards Action With Expert Review. 256 to 65535: Specification Required. greater than 65535: Expert Review. Strings of length 1: Standards Action With Expert Review. Strings of length 2: Specification Required. Strings of length greater than 2: Expert Review. Francesca Palombini Marco Tiloca Rikard Höglund
ACE Groupcomm Policies RFC 9594 less than -65536: Private Use. -65536 to -257: Specification Required. -256 to 255: Standards Action With Expert Review. 256 to 65535: Specification Required. greater than 65535: Expert Review. Strings of length 1: Standards Action With Expert Review. Strings of length 2: Specification Required. Strings of length greater than 2: Expert Review. Francesca Palombini Marco Tiloca Rikard Höglund
ACE Groupcomm Profiles RFC 9594 less than -65536: Private Use. -65536 to -257: Specification Required. -256 to 255: Standards Action With Expert Review. 256 to 65535: Specification Required. greater than 65535: Expert Review. Francesca Palombini Marco Tiloca Rikard Höglund
ACE Groupcomm Rekeying Schemes RFC 9594 less than -65536: Private Use. -65536 to -257: Specification Required. -256 to 255: Standards Action With Expert Review. 256 to 65535: Specification Required. greater than 65535: Expert Review. Francesca Palombini Marco Tiloca Rikard Höglund
ACE Profiles RFC 9200 less than -65536: Private Use. -65536 to -257: Specification Required. -256 to 255: Standards Action. 256 to 65535: Specification Required. greater than 65535: Expert Review. Göran Selander
ACE Token Revocation List Errors RFC 9770 less than -65536: Private Use. -65536 to -257: Specification Required. -256 to 255: Standards Action With Expert Review. 256 to 65535: Specification Required. greater than 65535: Expert Review. Marco Tiloca Marco Rasori
ACE Token Revocation List Parameters RFC 9770 less than -65536: Private Use. -65536 to -257: Specification Required. -256 to 255: Standards Action With Expert Review. 256 to 65535: Specification Required. greater than 65535: Expert Review. Marco Tiloca Marco Rasori
Group OSCORE Admin Permissions draft-ietf-ace-oscore-gm-admin-17 0-65535: Expert Review. greater than 65535: Private Use.
Group OSCORE Roles draft-ietf-ace-key-groupcomm-oscore-21 0-65535: Expert Review. greater than 65535: Private Use.
OAuth Access Token Type CBOR Mappings RFC 9200 less than -65536: Private Use. -65536 or greater: Expert Review. Göran Selander
OAuth Error Code CBOR Mappings RFC 9200 less than -65536: Private Use. -65536 or greater: Expert Review. Göran Selander
OAuth Grant Type CBOR Mappings RFC 9200 less than -65536: Private Use. -65536 or greater: Expert Review. Göran Selander
OAuth Parameters CBOR Mappings RFC 9200 less than -65536: Private Use. -65536 or greater: Expert Review. Göran Selander
OAuth Token Introspection Response CBOR Mappings RFC 9200 less than -65536: Private Use. -65536 or greater: Expert Review. Göran Selander
OSCORE Security Context Parameters RFC 9203 less than -65536: Private Use. -65536 to -257: Specification Required. -256 to 255: Standards Action With Expert Review. 256 to 65535: Specification Required. greater than 65535: Expert Review. Strings of length 1: Standards Action With Expert Review. Strings of length 2: Specification Required. Strings of length greater than 2: Expert Review. Göran Selander
Sequence Number Synchronization Methods RFC 9594 less than -65536: Private Use. -65536 to -257: Specification Required. -256 to 255: Standards Action With Expert Review. 256 to 65535: Specification Required. greater than 65535: Expert Review. Strings of length 1: Standards Action With Expert Review. Strings of length 2: Specification Required. Strings of length greater than 2: Expert Review. Francesca Palombini Marco Tiloca Rikard Höglund
Authentication and Key Agreement (AKA)
AKA-Version Namespace RFC 3310 Expert Review Vesa Torvinen (primary) Jari Arkko (secondary)
Authentication Method Reference Values
Authentication Method Reference Values RFC 8176 Expert Review John Bradley Mike Jones
Authentication Option Name Spaces
Algorithm Name Space Values RFC 3118 IETF Review
Protocol Name Space Values RFC 3118 IETF Review
RDM Name Space Values RFC 3118 IETF Review
Authentication, Authorization, and Accounting (AAA) Parameters
Application IDs RFC 6733, RFC 6942 0-16777215: Specification Required. 16777216-4294967294: First Come First Served.
AVP Codes RFC 6733 block allocation (release of more than three AVPs at a time for a given purpose): IETF Review. other allocation: Specification Required. Lionel Morand (primary) Jouni Korhonen (secondary)
AVP Flags Value RFC 6733 Standards Action
AVP Specific Values RFC 6733 IETF Review (unless otherwise specified)
Command Codes RFC 6733, RFC 5719 0-255: Reserved for RADIUS backward compatibility. 256-8388607: IETF Review. 8388608-16777213: First Come First Served with specification.
Command Flags RFC 6733 Standards Action
Mobility Capability Registry RFC 5447 Specification Required Jouni Korhonen
QoS Profiles RFC 5624 0-511: Standards Action. 512-32767: Specification Required. 32768-4294967295: Reserved.
Author Domain Signing Practices (ADSP) Parameters
ADSP Outbound Signing Practices RFC 5617 Registry closed
ADSP Specification Tags RFC 5617 Registry closed
Automated Certificate Management Environment (ACME) Protocol
ACME Account Object Fields RFC 8555 Specification Required Richard Barnes Aaron Gable
ACME Authority Token Challenge Types RFC 9447 Specification Required Mary Barnes Aaron Gable
ACME Authorization Object Fields RFC 8555 Specification Required Richard Barnes Aaron Gable
ACME Directory Metadata Auto-Renewal Fields RFC 8739 Specification Required Yaron Sheffer Diego R. Lopez Thomas Fossati Aaron Gable
ACME Directory Metadata Fields RFC 8555 Specification Required Richard Barnes Aaron Gable
ACME Error Types RFC 8555 Specification Required Richard Barnes Aaron Gable
ACME Identifier Types RFC 8555 Specification Required Richard Barnes Aaron Gable
ACME Order Auto-Renewal Fields RFC 8739 Specification Required Yaron Sheffer Diego R. Lopez Thomas Fossati Aaron Gable
ACME Order Object Fields RFC 8555 Specification Required Richard Barnes Aaron Gable
ACME RenewalInfo Object Fields RFC 9773 Specification Required Richard Barnes Aaron Gable
ACME Resource Types RFC 8555 Specification Required Richard Barnes Aaron Gable
ACME Validation Methods RFC 8555 Specification Required Richard Barnes Aaron Gable
STAR Delegation CSR Template Extensions RFC 9115 Specification Required Yaron Sheffer Diego R. Lopez Thomas Fossati Aaron Gable
Automatic Responses to Electronic Mail Parameters
Auto-Submitted Header Field Keywords RFC 5436 Specification Required
Auto-Submitted header field optional parameters RFC 3834 IETF Review
Autonomic Control Plane (ACP)
ACP Address Type RFC 8994 Standards Action
Autonomous System (AS) Numbers
16-bit Autonomous System Numbers RFC 1930, RFC 5398, RFC 6996, RFC 7249 RIR request to the IANA or IETF Review. Allocated following the Global Policy published at http://www.icann.org/en/resources/policy/global-addressing.
32-bit Autonomous System Numbers RFC 1930, RFC 5398, RFC 6793, RFC 6996, RFC 7249 RIR request to the IANA or IETF Review. Allocated following the Global Policy published at http://www.icann.org/en/resources/policy/global-addressing.
Special-Purpose AS Numbers RFC 7249 IETF Review
Babel Routing Protocol
Babel Address Encodings RFC 8966 0-223: Specification Required. 224-254: Experimental Use. Juliusz Chroboczek Donald Eastlake
Babel Hello Flags Values RFC 8966 Specification Required Juliusz Chroboczek Donald Eastlake
Babel Sub-TLV Types RFC 8966 0-111: Specification Required. 112-126: Experimental Use. 128-239: Specification Required. 240-254: Experimental Use. Juliusz Chroboczek Donald Eastlake
Babel TLV Types RFC 8966 0-223: Specification Required. 224-254: Experimental Use. Juliusz Chroboczek Donald Eastlake
Babel Update Flags Values RFC 8966 Specification Required Juliusz Chroboczek Donald Eastlake
Battery Technologies
Battery Technologies RFC 7577 Expert Review
BGP Monitoring Protocol (BMP) Parameters
BMP Initiation Information TLVs RFC 7854, RFC 9069, RFC 9515, RFC 9736 0-32767: Standards Action. 32768-65530: First Come First Served. 65531-65534: Experimental Use.
BMP Message Types RFC 7854 0-127: Standards Action. 128-250: Specification Required. 251-254: Experimental Use. John G. Scudder Rex Fernando (rex) Paolo Lucente
BMP Peer Down Reason Codes RFC 7854 0-127: Standards Action. 128-250: Specification Required. 251-254: Experimental Use. John G. Scudder Rex Fernando (rex) Paolo Lucente
BMP Peer Flags for Loc-RIB Instance Peer Type 3 RFC 9069 Standards Action
BMP Peer Flags for Peer Types 0 through 2 RFC 7854, RFC 9069 Standards Action
BMP Peer Types