2007-04-25 2026-03-05 Please also see: Standards Action 0x000001 V6-bit 0x000002 E-bit 0x000004 Deprecated 0x000008 N-bit 0x000010 R-Bit 0x000020 DC-bit 0x000040 Reserved for OSPFv2 migrated options 0x000080 Reserved for OSPFv2 migrated options 0x000100 AF-bit 0x000200 L-bit 0x000400 AT-bit 0-255 IETF Review 256-8175 Reserved IANA does not assign 8176-8183 Experimentation IANA does not assign 8184-8190 Vendor Private Use IANA does not assign 8191 Reserved IANA does not assign 0 Reserved 1 Router-LSA 2 Network-LSA 3 Inter-Area-Prefix-LSA 4 Inter-Area-Router-LSA 5 AS-External-LSA 6 Deprecated 7 NSSA-LSA 8 Link-LSA 9 Intra-Area-Prefix-LSA 10 Intra-Area-TE-LSA 11 GRACE-LSA 12 OSPFv3 Router Information (RI) LSA 13 Inter-AS-TE-v3 LSA 14 OSPFv3 L1VPN LSA 15 OSPFv3 Autoconfiguration (AC) LSA 16 OSPFv3 Dynamic Flooding LSA 17-32 Unassigned 33 E-Router-LSA 34 E-Network-LSA 35 E-Inter-Area-Prefix-LSA 36 E-Inter-Area-Router-LSA 37 E-AS-External-LSA 38 Unused (Not to be allocated) 39 E-Type-7-LSA 40 E-Link-LSA 41 E-Intra-Area-Prefix-LSA 42 SRv6 Locator LSA RFC9513, Section 7 43-255 Unassigned 256-8175 Reserved 8176-8183 Experimentation 8184-8190 Vendor Private Use 8191 Reserved Standards Action 0x01 NU-bit 0x02 LA-bit 0x04 Deprecated 0x08 P-bit 0x10 DN-bit 0x20 N-bit 0x40 E-Flag (ELC Flag) 0x80 AC-bit RFC9513, Section 6 0-127 Standards Action 128-255 Reserved 0 Reserved 1 Point-to-Point connection to another router 2 Transit Network 3 Reserved 4 Virtual Link 5-127 Unassigned 128-255 Reserved Standards Action 0x01 B-bit 0x02 E-bit 0x04 V-bit 0x08 Deprecated 0x10 Nt-bit IETF Review 0x01 U-bit Standards Action These values for instance ID are applicable when is used to support multiple address families. The instance ID field may be used for applications other than the support of multiple address families. 0 Base IPv6 Unicast AF 1-31 Base IPv6 Unicast AF dependent on local policy 32 Base IPv6 Multicast 33-63 IPv6 Multicast AFs dependent on local policy 64 Base IPv4 Unicast AF 65-95 IPv4 Unicast AFs dependent on local policy 96 Base IPv4 Multicast 97-127 IPv4 Multicast AFs dependent on local policy 128-191 Unassigned 192-255 Reserved for Private Use IETF Review or IESG Approval 0 Reserved 1 Router-Hardware-Fingerprint TLV 2-65534 Unassigned 65535 Autoconfiguration-Experiment-TLV 9-32767 IETF Review or IESG Approval 33024-45055 First Come First Served 0 Reserved 1 Router-Link TLV 2 Attached-Routers TLV 3 Inter-Area-Prefix TLV 4 Inter-Area-Router TLV 5 External-Prefix TLV 6 Intra-Area-Prefix TLV 7 IPv6 Link-Local Address TLV 8 IPv4 Link-Local Address TLV 9 OSPFv3 Extended Prefix Range TLV 10-32767 Unassigned 32768-33023 Reserved for Experimental Use 33024-45055 Unassigned 45056-65535 Reserved 4-32767 IETF Review or IESG Approval 33024-45055 First Come First Served The "L2BM" column indicates applicability to the L2 Bundle Attributes Member sub-TLV. The options for the "L2BM" column are: Y - This sub-TLV MAY appear in the L2 Bundle Member Attributes sub-TLV. N - This sub-TLV MUST NOT appear in the L2 Bundle Member Attributes sub-TLV. X - This is not a sub-TLV of the Router-Link TLV; it MUST NOT appear in the L2 Bundle Member Attributes sub-TLV. Allocations made in this registry for sub-TLVs that are associated with OSPFv3 Extended TLVs related to prefix advertisements MUST be evaluated for their applicability as OSPFv3 SRv6 Locator sub-TLVs, which are required to be allocated in the "OSPFv3 SRv6 Locator LSA Sub-TLVs" registry at . 0 Reserved 1 IPv6-Forwarding-Address sub-TLV X 2 IPv4-Forwarding-Address sub-TLV X 3 Route-Tag sub-TLV X 4 Prefix SID sub-TLV X 5 Adj-SID sub-TLV Y 6 LAN Adj-SID sub-TLV Y 7 SID/Label sub-TLV N 8 Graceful-Link-Shutdown sub-TLV N 9 OSPFv3 Link MSD N 10 OSPFv3 Link Attributes Bits Y 11 Application-Specific Link Attributes Y 12 Shared Risk Link Group Y 13 Unidirectional Link Delay Y 14 Min/Max Unidirectional Link Delay Y 15 Unidirectional Delay Variation Y 16 Unidirectional Link Loss Y 17 Unidirectional Residual Bandwidth Y 18 Unidirectional Available Bandwidth Y 19 Unidirectional Utilized Bandwidth Y 20 Administrative Group Y 21 Extended Administrative Group Y 22 TE Metric Y 23 Maximum link bandwidth Y 24 Local Interface IPv6 Address N 25 Remote Interface IPv6 Address N 26 Flexible Algorithm Prefix Metric (FAPM) X RFC9350, Section 9 27 Prefix Source OSPF Router-ID X 28 Prefix Source Router Address X 29 L2 Bundle Member Attributes N 30 SRv6 SID Structure Y RFC9513, Section 10 31 SRv6 End.X SID Y RFC9513, Section 9.1 32 SRv6 LAN End.X SID Y RFC9513, Section 9.2 33 OSPF Flexible Algorithm ASBR Metric X RFC9350, Section 10.2 34 Generic Metric Y RFC9843, Section 2.2 35 OSPFv3 IP Algorithm Prefix Reachability X RFC9502, Section 6.4 36 OSPFv3 IP Flexible Algorithm ASBR Metric X RFC9502, Section 6.5 37 OSPFv3 Prefix Extended Flags X 38 BIER PHP Request X 39 Administrative Tag X 40-32767 Unassigned 32768-33023 Reserved for Experimental Use 33024-45055 Unassigned 45056-65535 Reserved Standards Action 0 Unassigned 1 O-flag RFC9513, Section 2 2-15 Unassigned Standards Action 0-7 Unassigned Standards Action 0 B-flag RFC9513, Sections 9.1 and 9.2 1 S-flag RFC9513, Sections 9.1 and 9.2 2 P-flag RFC9513, Sections 9.1 and 9.2 3-7 Unassigned 0-32767 IETF Review or IESG Approval 33024-45055 First Come First Served 0 Reserved 1 SRv6 Locator RFC9513, Section 7.1 2-32767 Unassigned 32768-33023 Reserved for Experimental Use 33024-45055 Unassigned 45056-65535 Reserved 0-32767 IETF Review or IESG Approval 33024-45055 First Come First Served Allocations made in this registry for sub-TLVs that are associated with OSPFv3 SRv6 Locator TLVs MUST be evaluated for their applicability as OSPFv3 Extended-LSA sub-TLVs, which are required to be allocated in the “OSPFv3 Extended-LSA Sub-TLVs" registry at . 0 Reserved 1 SRv6 End SID RFC9513, Section 8 2 IPv6-Forwarding-Address RFC9513, Section 7.2 3 Route-Tag RFC9513, Section 7.2 4 Prefix Source OSPF Router-ID RFC9513, Section 7.2 5 Prefix Source Router Address RFC9513, Section 7.2 6 Administrative Tag 7-9 Unassigned 10 SRv6 SID Structure RFC9513, Section 10 11-32767 Unassigned 32768-33023 Reserved for Experimental Use 33024-45055 Unassigned 45056-65535 Reserved IETF Review Per , IANA will add subsequent blocks of 32 bits upon exhaustion of the preceding 32-bit block. 0 U-Flag RFC9929, Section 4.2 1 UP-Flag RFC9929, Section 4.2 2-31 Unassigned