Value	Name	Description	Reference
0	SPF	Shortest Path First (SPF) algorithm based on link metric. This is the standard shortest path algorithm as computed by the IGP protocol. Consistent with the deployed practice for link-state protocols, Algorithm 0 permits any node to overwrite the SPF path with a different path based on its local policy.	[RFC 8665]
1	Strict SPF	Strict Shortest Path First (SPF) algorithm based on link metric. The algorithm is identical to Algorithm 0 but Algorithm 1 requires that all nodes along the path will honor the SPF routing decision. Local policy at the node claiming support for Algorithm 1 MUST NOT alter the SPF paths computed by Algorithm 1.	[RFC 8665]
2-127		Unassigned
128-255		Flexible Algorithms	[RFC9350, Section 4]

Value	Name	Data Plane	Reference
0	Reserved		[RFC 8491]
1	Base MPLS Imposition MSD	MPLS	[RFC 8491]
2	ERLD-MSD	MPLS	[RFC 9088]
3	Readable Label Depth	MPLS	[RFC 9789][RFC-ietf-mpls-mna-ps-hdr-19]
4-40	Unassigned
41	SRH Max SL	SRv6	[RFC 9352]
42	SRH Max End Pop	SRv6	[RFC 9352]
43	Unassigned
44	SRH Max H.encaps	SRv6	[RFC 9352]
45	SRH Max End D	SRv6	[RFC 9352]
46-250	Unassigned
251-254	Experimental Use		[RFC 8491]
255	Reserved		[RFC 8491]

Bit	Name	Reference
0	RSVP-TE (R-bit)	[RFC 9479]
1	Segment Routing Policy (S-bit)	[RFC 9479]
2	Loop-Free Alternate (F-bit)	[RFC 9479]
3	Flexible Algorithm (X-bit)	[RFC9350, Section 12]
4-63	Unassigned

Type	Name	Description	Reference	Allowed in Generic-Metric
0	IGP Metric	IGP Metric	[RFC9350, Section 5.1]	No
1	Min Unidirectional Link Delay	Min Unidirectional Link Delay as defined in [RFC8570, Section 4.2] and [RFC7471, Section 4.2]	[RFC9350, Section 5.1]	No
2	TE Default Metric	Traffic Engineering Default Metric as defined in [RFC5305, Section 3.7] and Traffic Engineering Metric as defined in [RFC3630, Section 2.5.5]	[RFC9350, Section 5.1]	No
3	Bandwidth Metric	Bandwidth Metric	[RFC 9843]	Yes
4-127		Unassigned
128-255		Reserved for User-Defined Metric	[RFC 9843]	Yes

Bit	Capability Description	Reference
0	Path computation with GMPLS link constraints	[RFC 5088]
1	Bidirectional path computation	[RFC 5088]
2	Diverse path computation	[RFC 5088]
3	Load-balanced path computation	[RFC 5088]
4	Synchronized paths computation	[RFC 5088]
5	Support for multiple objective functions	[RFC 5088]
6	Support for additive path constraints (max hop count, etc.)	[RFC 5088]
7	Support for request prioritization	[RFC 5088]
8	Support for multiple requests per message	[RFC 5088]
9	Global Concurrent Optimization (GCO)	[RFC 5557]
10	P2MP path computation	[RFC 8306]
11	Active stateful PCE capability	[RFC 8231]
12	Passive stateful PCE capability	[RFC 8231]
13	Active Stateful PCE with P2MP	[RFC 8623]
14	Passive Stateful PCE with P2MP	[RFC 8623]
15	Stateful PCE Initiation with P2MP	[RFC 8623]
16	FlowSpec	[RFC 9168]
17	TCP-AO Support	[RFC 9353]
18	PCEP over TLS support	[RFC 9353]
19-31	Unassigned

Value	Description	Reference
0	Reserved	[RFC 9353][RFC 5088]
1	PCE-ADDRESS	[RFC 9353][RFC 5088]
2	PATH-SCOPE	[RFC 9353][RFC 5088]
3	PCE-DOMAIN	[RFC 9353][RFC 5088]
4	NEIG-PCE-DOMAIN	[RFC 9353][RFC 5088]
5	PCE-CAP-FLAGS	[RFC 9353][RFC 5088]
6	KEY-ID	[RFC 9353]
7	KEY-CHAIN-NAME	[RFC 9353]
8-65535	Unassigned

Value	Description	Reference
0	Reserved for centralized mode	[RFC 9667]
1	Modified MANET Reduction	[draft-ietf-lsr-distoptflood-13]
2-127	Unassigned
128-254	Reserved for Private Use	[RFC 9667]
255	Reserved	[RFC 9667]

Sequence Number	Description	Reference
1	Check if any exclude Administrative Group rule is part of the Flex-Algorithm Definition. If such exclude rule exists, check if any color that is part of the exclude rule is also set on the link. If such a color is set, the link MUST be pruned from the computation.	[RFC9350, Section 13]
2	Check if any exclude SRLG rule is part of the Flex-Algorithm Definition. If such exclude rule exists, check if the link is part of any SRLG that is also part of the SRLG exclude rule. If the link is part of such SRLG, the link MUST be pruned from the computation.	[RFC9350, Section 13]
3	Check if any include-any Administrative Group rule is part of the Flex-Algorithm Definition. If such include-any rule exists, check if any color that is part of the include-any rule is also set on the link. If no such color is set, the link MUST be pruned from the computation.	[RFC9350, Section 13]
4	Check if any include-all Administrative Group rule is part of the Flex-Algorithm Definition. If such include-all rule exists, check if all colors that are part of the include-all rule are also set on the link. If all such colors are not set on the link, the link MUST be pruned from the computation.	[RFC9350, Section 13]
5	If the Flex-Algorithm Definition uses something other than the IGP metric (Section 5 of [RFC 9350]), and such metric is not advertised for the particular link in a topology for which the computation is done, such link MUST be pruned from the computation. A metric of value 0 MUST NOT be assumed in such a case.	[RFC9350, Section 13]
6	Check if any exclude FAEMB rule is part of the Flex-Algorithm definition. If such exclude rule exists and the link has Maximum Link Bandwidth advertised, check if the link bandwidth satisfies the FAEMB rule. If the link does not satisfy the FAEMB rule, the link MUST be pruned from the Flex-Algorithm computation.	[RFC9843, Section 6]
7	Check if any exclude FAEMD rule is part of the Flex-Algorithm definition. If such exclude rule exists and the link has Min Unidirectional link delay advertised, check if the link delay satisfies the FAEMD rule. If the link does not satisfy the FAEMD rule, the link MUST be pruned from the Flex-Algorithm computation.	[RFC9843, Section 6]
8	Check if any exclude reverse Admin Group rule is part of the Flex-Algorithm definition. If such exclude rule exists, check if any Admin Group that is part of the exclude rule is also set on the link in the reverse direction. If such Admin Group is set on the link in the reverse direction, the link MUST be pruned from the computation.	[RFC9917, Section 11]
9	Check if any include-any reverse Admin Group rule is part of the Flex-Algorithm definition. If such include-any rule exists, check if any Admin Group that is part of the include-any rule is also set on the link in the reverse direction. If no such Admin Group is set on the link in the reverse direction, the link MUST be pruned from the computation.	[RFC9917, Section 11]
10	Check if any include-all reverse Admin Group rule is part of the Flex-Algorithm definition. If such include-all rule exists, check if all Admin Groups that are part of the include-all rule are also set on the link in the reverse direction. If all such Admin Groups are not set on the link in the reverse direction, the link MUST be pruned from the computation.	[RFC9917, Section 11]

Range	Registration Procedures
0-127	Standards Action
128-255	User-Defined Metric

Interior Gateway Protocol (IGP) Parameters

IGP Algorithm Types

IGP MSD-Types

Link Attribute Application Identifiers

IGP Metric-Type

IGP Flexible Algorithm Definition Flags

Path Computation Element (PCE) Capability Flags

PCE Discovery (PCED) Sub-TLV Type Indicators

IGP Algorithm Type For Computing Flooding Topology

IGP Flex-Algorithm Path Computation Rules