rfc9492v4.txt   rfc9492.txt 
Internet Engineering Task Force (IETF) P. Psenak, Ed. Internet Engineering Task Force (IETF) P. Psenak, Ed.
Request for Comments: 9492 L. Ginsberg Request for Comments: 9492 L. Ginsberg
Obsoletes: 8920 Cisco Systems Obsoletes: 8920 Cisco Systems
Category: Standards Track W. Henderickx Category: Standards Track W. Henderickx
ISSN: 2070-1721 Nokia ISSN: 2070-1721 Nokia
J. Tantsura J. Tantsura
Nvidia Nvidia
J. Drake J. Drake
Juniper Networks Juniper Networks
September 2023 October 2023
OSPF Application-Specific Link Attributes OSPF Application-Specific Link Attributes
Abstract Abstract
Existing traffic-engineering-related link attribute advertisements Existing traffic-engineering-related link attribute advertisements
have been defined and are used in RSVP-TE deployments. Since the have been defined and are used in RSVP-TE deployments. Since the
original RSVP-TE use case was defined, additional applications such original RSVP-TE use case was defined, additional applications such
as Segment Routing (SR) Policy and Loop-Free Alternates (LFAs) that as Segment Routing (SR) Policy and Loop-Free Alternates (LFAs) that
also make use of the link attribute advertisements have been defined. also make use of the link attribute advertisements have been defined.
skipping to change at line 186 skipping to change at line 186
applications. There is no requirement for the link attributes applications. There is no requirement for the link attributes
advertised on a given link used by SR Policy to be identical to the advertised on a given link used by SR Policy to be identical to the
link attributes advertised on that same link used by RSVP-TE; thus, link attributes advertised on that same link used by RSVP-TE; thus,
there is a clear requirement to indicate independently which link there is a clear requirement to indicate independently which link
attribute advertisements are to be used by each application. attribute advertisements are to be used by each application.
As the number of applications that may wish to utilize link As the number of applications that may wish to utilize link
attributes may grow in the future, an additional requirement is that attributes may grow in the future, an additional requirement is that
the extensions defined allow the association of additional the extensions defined allow the association of additional
applications to link attributes without altering the format of the applications to link attributes without altering the format of the
advertisements or introducing new backwards-compatibility issues. advertisements or introducing backwards-compatibility issues.
Finally, there may still be many cases where a single attribute value Finally, there may still be many cases where a single attribute value
can be shared among multiple applications, so the solution must can be shared among multiple applications, so the solution must
minimize advertising duplicate link/attribute pairs whenever minimize advertising duplicate link/attribute pairs whenever
possible. possible.
3. Existing Advertisement of Link Attributes 3. Existing Advertisement of Link Attributes
There are existing advertisements used in support of RSVP-TE. These There are existing advertisements used in support of RSVP-TE. These
advertisements are carried in the OSPFv2 TE Opaque Link State advertisements are carried in the OSPFv2 TE Opaque Link State
skipping to change at line 308 skipping to change at line 308
| Link Attribute sub-TLVs | | Link Attribute sub-TLVs |
+- -+ +- -+
| ... | | ... |
where: where:
Type: 10 (OSPFv2), 11 (OSPFv3) Type: 10 (OSPFv2), 11 (OSPFv3)
Length: Variable Length: Variable
SABM Length: Standard Application Identifier Bit Mask Length in SABM Length:
octets. The value MUST be 0, 4, or 8. If the Standard Standard Application Identifier Bit Mask Length in octets. The
Application Identifier Bit Mask is not present, the SABM Length value MUST be 0, 4, or 8. If the Standard Application Identifier
MUST be set to 0. Bit Mask is not present, the SABM Length MUST be set to 0.
UDABM Length: User-Defined Application Identifier Bit Mask Length in UDABM Length:
octets. The value MUST be 0, 4, or 8. If the User-Defined User-Defined Application Identifier Bit Mask Length in octets.
Application Identifier Bit Mask is not present, the UDABM Length The value MUST be 0, 4, or 8. If the User-Defined Application
MUST be set to 0. Identifier Bit Mask is not present, the UDABM Length MUST be set
to 0.
Standard Application Identifier Bit Mask: Optional set of bits, Standard Application Identifier Bit Mask: Optional set of bits,
where each bit represents a single standard application. Bits are where each bit represents a single standard application. Bits are
defined in the "Link Attribute Application Identifiers" registry, defined in the "Link Attribute Application Identifiers" registry,
which is defined in [RFC9479]. Current assignments are repeated which is defined in [RFC9479]. Current assignments are repeated
here for informational purposes: here for informational purposes:
0 1 2 3 4 5 6 7 ... 0 1 2 3 4 5 6 7 ...
+-+-+-+-+-+-+-+-+... +-+-+-+-+-+-+-+-+...
|R|S|F| ... |R|S|F| ...
+-+-+-+-+-+-+-+-+... +-+-+-+-+-+-+-+-+...
Bit 0 (R-bit): RSVP-TE. Bit 0 (R-bit): RSVP-TE.
Bit 1 (S-bit): SR Policy (this is data plane independent). Bit 1 (S-bit): SR Policy (this is data plane independent).
Bit 2 (F-bit): Loop-Free Alternate (includes all LFA types). Bit 2 (F-bit): Loop-Free Alternate (includes all LFA types).
User-Defined Application Identifier Bit Mask: Optional set of bits, User-Defined Application Identifier Bit Mask:
where each bit represents a single user-defined application. Optional set of bits, where each bit represents a single user-
defined application.
If the SABM or UDABM Length is other than 0, 4, or 8, the ASLA sub- If the SABM or UDABM Length is other than 0, 4, or 8, the ASLA sub-
TLV MUST be ignored by the receiver. TLV MUST be ignored by the receiver.
Standard Application Identifier Bits are defined and sent starting Standard Application Identifier Bits are defined and sent starting
with bit 0. Undefined bits that are transmitted MUST be transmitted with bit 0. Undefined bits that are transmitted MUST be transmitted
as 0 and MUST be ignored on receipt. Bits that are not transmitted as 0 and MUST be ignored on receipt. Bits that are not transmitted
MUST be treated as if they are set to 0 on receipt. Bits that are MUST be treated as if they are set to 0 on receipt. Bits that are
not supported by an implementation MUST be ignored on receipt. not supported by an implementation MUST be ignored on receipt.
skipping to change at line 950 skipping to change at line 952
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>. May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8362] Lindem, A., Roy, A., Goethals, D., Reddy Vallem, V., and [RFC8362] Lindem, A., Roy, A., Goethals, D., Reddy Vallem, V., and
F. Baker, "OSPFv3 Link State Advertisement (LSA) F. Baker, "OSPFv3 Link State Advertisement (LSA)
Extensibility", RFC 8362, DOI 10.17487/RFC8362, April Extensibility", RFC 8362, DOI 10.17487/RFC8362, April
2018, <https://www.rfc-editor.org/info/rfc8362>. 2018, <https://www.rfc-editor.org/info/rfc8362>.
[RFC9479] Ginsberg, L., Psenak, P., Previdi, S., Henderickx, W., and [RFC9479] Ginsberg, L., Psenak, P., Previdi, S., Henderickx, W., and
J. Drake, "IS-IS Application-Specific Link Attributes", J. Drake, "IS-IS Application-Specific Link Attributes",
RFC 9479, DOI 10.17487/RFC9479, September 2023, RFC 9479, DOI 10.17487/RFC9479, October 2023,
<https://www.rfc-editor.org/info/rfc9479>. <https://www.rfc-editor.org/info/rfc9479>.
16.2. Informative References 16.2. Informative References
[RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V., [RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V.,
and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP
Tunnels", RFC 3209, DOI 10.17487/RFC3209, December 2001, Tunnels", RFC 3209, DOI 10.17487/RFC3209, December 2001,
<https://www.rfc-editor.org/info/rfc3209>. <https://www.rfc-editor.org/info/rfc3209>.
[RFC4552] Gupta, M. and N. Melam, "Authentication/Confidentiality [RFC4552] Gupta, M. and N. Melam, "Authentication/Confidentiality
 End of changes. 6 change blocks. 
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