Internet Protocol Version 6 (IPv6) Parameters
- Last Updated
- 2025-06-26
- Available Formats
-

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Registries Included Below
- Next Header Types
- IPv6 Extension Header Types
- Destination Options and Hop-by-Hop Options
- Routing Types
- RPL-option-TLV
- TaggerId Types
- Segment Routing Header Flags
- Segment Routing Header TLVs
Next Header Types
- Reference
- [RFC8200][RFC2780][RFC7045]
- Note
-
This registry has been closed in favor of the IPv6 Extension Header Types registry, also located at [IANA registry ipv6-parameters].
IPv6 Extension Header Types
- Registration Procedure(s)
-
Standards Action or IESG Approval
- Reference
- [RFC2780][RFC5237][RFC7045][RFC-ietf-netmod-acl-extensions-17]
- Note
-
The "IPv6 Extension Header" field in the Assigned Internet Protocol Numbers registry at [IANA registry protocol-numbers] should be updated for any Protocol Number added to this registry. - Note
-
When a new code is assigned to an IPv6 Extension Header, the next available free bit in [IPFIX ipv6ExtensionHeaders Bits] is selected for this new Extension Header. [IPFIX ipv6ExtensionHeaders Bits] is updated accordingly. Modifications to existing registrations must be mirrored in [IPFIX ipv6ExtensionHeaders Bits]. - Note
-
When this registry is modified, the YANG module "iana-ipv6-ext-types" [IANA registry yang-parameters] must be updated as defined in [RFC-ietf-netmod-acl-extensions-17]. - Available Formats
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CSV
| Protocol Number | Description | Reference |
|---|---|---|
| 0 | IPv6 Hop-by-Hop Option | [RFC8200] |
| 43 | Routing Header for IPv6 | [RFC8200][RFC5095] |
| 44 | Fragment Header for IPv6 | [RFC8200] |
| 50 | Encapsulating Security Payload | [RFC4303] |
| 51 | Authentication Header | [RFC4302] |
| 60 | Destination Options for IPv6 | [RFC8200] |
| 135 | Mobility Header | [RFC6275] |
| 139 | Host Identity Protocol | [RFC7401] |
| 140 | Shim6 Protocol | [RFC5533] |
| 253 | Use for experimentation and testing | [RFC3692][RFC4727] |
| 254 | Use for experimentation and testing | [RFC3692][RFC4727] |
Destination Options and Hop-by-Hop Options
- Registration Procedure(s)
-
IESG Approval, IETF Review or Standards Action
- Reference
- [RFC8200][RFC2780][RFC9673]
- Note
-
From [RFC8200] IPv6 Option Types are 8-bit values, structured as three subfields, are defined in Section 4.2 of [RFC8200]. Each distinct 8-bit Option Type identifies a different option, i.e., the high-order 3 bits are considered part of the option identification. However, it is recommended that Option Types be assigned with distinct values in the "rest" subfield, until and unless that 5-bit space becomes full. - Available Formats
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CSV
| Hex Value | Binary Value | Description | Reference | ||
|---|---|---|---|---|---|
| act | chg | rest | |||
| 0x00 | 00 | 0 | 00000 | Pad1 | [RFC2460] |
| 0x01 | 00 | 0 | 00001 | PadN | [RFC2460] |
| 0xC2 | 11 | 0 | 00010 | Jumbo Payload | [RFC2675] |
| 0x23 | 00 | 1 | 00011 | RPL Option | [RFC9008] |
| 0x63 | 01 | 1 | 00011 | RPL Option (DEPRECATED) | [RFC6553][RFC9008] |
| 0x04 | 00 | 0 | 00100 | Tunnel Encapsulation Limit | [RFC2473] |
| 0x05 | 00 | 0 | 00101 | Router Alert (DEPRECATED for New Protocols) | [RFC2711][RFC9805] |
| 0x26 | 00 | 1 | 00110 | Quick-Start | [RFC4782][RFC Errata 2034] |
| 0x07 | 00 | 0 | 00111 | CALIPSO | [RFC5570] |
| 0x08 | 00 | 0 | 01000 | SMF_DPD | [RFC6621] |
| 0xC9 | 11 | 0 | 01001 | Home Address | [RFC6275] |
| 0x8A | 10 | 0 | 01010 | Endpoint Identification (DEPRECATED) | [[CHARLES LYNN]] |
| 0x8B | 10 | 0 | 01011 | ILNP Nonce | [RFC6744] |
| 0x8C | 10 | 0 | 01100 | Line-Identification Option | [RFC6788] |
| 0x4D | 01 | 0 | 01101 | Deprecated | [RFC7731] |
| 0x6D | 01 | 1 | 01101 | MPL Option | [RFC7731] |
| 0xEE | 11 | 1 | 01110 | IP_DFF | [RFC6971] |
| 0x0F | 00 | 0 | 01111 | Performance and Diagnostic Metrics (PDM) | [RFC8250] |
| 0x30 | 00 | 1 | 10000 | Minimum Path MTU Hop-by-Hop Option | [RFC9268] |
| 0x11 | 00 | 0 | 10001 | IOAM Destination Option and IOAM Hop-by-Hop Option | [RFC9486] |
| 0x31 | 00 | 1 | 10001 | IOAM Destination Option and IOAM Hop-by-Hop Option | [RFC9486] |
| 0x12 | 00 | 0 | 10010 | AltMark | [RFC9343] |
| 10011-11101 | Unassigned | ||||
| 0x1E | 00 | 0 | 11110 | RFC3692-style Experiment [1] | [RFC4727] |
| 0x3E | 00 | 1 | 11110 | RFC3692-style Experiment [1] | [RFC4727] |
| 0x5E | 01 | 0 | 11110 | RFC3692-style Experiment [1] | [RFC4727] |
| 0x7E | 01 | 1 | 11110 | RFC3692-style Experiment [1] | [RFC4727] |
| 0x9E | 10 | 0 | 11110 | RFC3692-style Experiment [1] | [RFC4727] |
| 0xBE | 10 | 1 | 11110 | RFC3692-style Experiment [1] | [RFC4727] |
| 0xDE | 11 | 0 | 11110 | RFC3692-style Experiment [1] | [RFC4727] |
| 0xFE | 11 | 1 | 11110 | RFC3692-style Experiment [1] | [RFC4727] |
| 11111 | Unassigned | ||||
Routing Types
- Registration Procedure(s)
-
IETF Review or IESG Approval
- Reference
- [RFC8200][RFC5871]
- Note
-
For Traffic Class related information, please see [RFC2474],[RFC3168], and [https://www.iana.org/assignments/dscp-registry]. For IPv6 Router Alert Option Values, please see: [https://www.iana.org/assignments/ipv6-routeralert-values] - Available Formats
-

CSV
| Value | Description | Reference |
|---|---|---|
| 0 | Source Route (DEPRECATED) | [RFC2460][RFC5095] |
| 1 | Nimrod (DEPRECATED 2009-05-06) | |
| 2 | Type 2 Routing Header | [RFC6275] |
| 3 | RPL Source Route Header | [RFC6554] |
| 4 | Segment Routing Header (SRH) | [RFC8754] |
| 5 | CRH-16 | [RFC9631] |
| 6 | CRH-32 | [RFC9631] |
| 7-252 | Unassigned | |
| 253 | RFC3692-style Experiment 1 [2] | [RFC4727] |
| 254 | RFC3692-style Experiment 2 [2] | [RFC4727] |
| 255 | Reserved |
RPL-option-TLV
- Registration Procedure(s)
-
IETF Review
- Reference
- [RFC6553]
- Available Formats
-

CSV
| Value | Description | Reference |
|---|---|---|
| 0-254 | Unassigned | |
| 255 | Reserved | [RFC6553] |
TaggerId Types
- Registration Procedure(s)
-
IETF Review
- Reference
- [RFC6621]
- Available Formats
-

CSV
| Type | Mnemonic | Description | Reference |
|---|---|---|---|
| 0 | NULL | No TaggerId field is present | [RFC6621] |
| 1 | DEFAULT | A TaggerId of non-specific context is present | [RFC6621] |
| 2 | IPv4 | A TaggerId representing an IPv4 address is present | [RFC6621] |
| 3 | IPv6 | A TaggerId representing an IPv6 address is present | [RFC6621] |
| 4-7 | Unassigned |
Segment Routing Header Flags
- Registration Procedure(s)
-
IETF Review
- Reference
- [RFC8754]
- Available Formats
-

CSV
| Bit | Description | Reference |
|---|---|---|
| 0-1 | Unassigned | |
| 2 | O-flag | [RFC9259] |
| 3-7 | Unassigned |
Segment Routing Header TLVs
- Registration Procedure(s)
-
IETF Review
- Reference
- [RFC8754][RFC Errata 7081]
- Note
-
0-127: TLVs that do not change en route. 128-255: TLVs that may change en route. - Available Formats
-

CSV
| Value | Description | Reference |
|---|---|---|
| 0 | Pad1 TLV | [RFC8754] |
| 1 | Reserved | [RFC8754] |
| 2 | Reserved | [RFC8754] |
| 3 | Reserved | [RFC8754] |
| 4 | PadN TLV | [RFC8754] |
| 5 | HMAC TLV | [RFC8754] |
| 6 | Reserved | [RFC8754] |
| 7-123 | Unassigned | |
| 124-126 | Experimentation and Test | [RFC8754] |
| 127 | Reserved | [RFC8754] |
| 128-251 | Unassigned | |
| 252-254 | Experimentation and Test | [RFC8754] |
| 255 | Reserved | [RFC8754] |
Footnotes
| [1] |
It is only appropriate to use these values in explicitly-configured experiments; they MUST NOT be shipped as defaults in implementations. See [RFC3692] for details. |
| [2] |
It is only appropriate to use these values in explicitly-configured experiments; they MUST NOT be shipped as defaults in implementations. See [RFC3692] for details. |