--- 1/draft-ietf-ospf-te-link-attr-reuse-11.txt 2020-05-19 02:13:03.970128618 -0700 +++ 2/draft-ietf-ospf-te-link-attr-reuse-12.txt 2020-05-19 02:13:04.014129734 -0700 @@ -1,24 +1,24 @@ LSR Working Group P. Psenak, Ed. Internet-Draft L. Ginsberg Intended status: Standards Track Cisco Systems -Expires: November 8, 2020 W. Henderickx +Expires: November 20, 2020 W. Henderickx Nokia J. Tantsura Apstra J. Drake Juniper Networks - May 7, 2020 + May 19, 2020 OSPF Link Traffic Engineering Attribute Reuse - draft-ietf-ospf-te-link-attr-reuse-11.txt + draft-ietf-ospf-te-link-attr-reuse-12.txt Abstract Existing traffic engineering related link attribute advertisements have been defined and are used in RSVP-TE deployments. Since the original RSVP-TE use case was defined, additional applications (e.g., Segment Routing Traffic Engineering, Loop Free Alternate) have been defined which also make use of the link attribute advertisements. In cases where multiple applications wish to make use of these link attributes the current advertisements do not support application @@ -35,21 +35,21 @@ Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at https://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." - This Internet-Draft will expire on November 8, 2020. + This Internet-Draft will expire on November 20, 2020. Copyright Notice Copyright (c) 2020 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents @@ -174,40 +174,40 @@ 1. Advertisement of the link attributes does not make the link part of the RSVP-TE topology. It avoids any conflicts and is fully compatible with [RFC3630] and [RFC5329]. 2. The OSPFv2 TE Opaque LSA and OSPFv3 Intra-Area-TE-LSA remains truly opaque to OSPFv2 and OSPFv3 as originally defined in [RFC3630] and [RFC5329] respectively. Their contents are not inspected by OSPF, that acts as a pure transport. - 3. There is clear distinction between link attributes used by RSVP- - TE and link attributes used by other OSPFv2 or OSPFv3 + 3. There is a clear distinction between link attributes used by + RSVP-TE and link attributes used by other OSPFv2 or OSPFv3 applications. 4. All link attributes that are used by other applications are advertised in a single LSA, the Extended Link Opaque LSA in OSPFv2 or the OSPFv3 E-Router-LSA [RFC8362] in OSPFv3. The disadvantage of this approach is that in rare cases, the same link attribute is advertised in both the TE Opaque and Extended Link Attribute LSAs in OSPFv2 or the Intra-Area-TE-LSA and E-Router-LSA in OSPFv3. Extended Link Opaque LSA [RFC7684] and E-Router-LSA [RFC8362] are used to advertise any link attributes used for non-RSVP-TE applications in OSPFv2 or OSPFv3 respectively, including those that have been originally defined for RSVP-TE applications (See Section 6). - TE link attributes used for RSVP-TE/GMPLS continue use OSPFv2 TE + TE link attributes used for RSVP-TE/GMPLS continue to use OSPFv2 TE Opaque LSA [RFC3630] and OSPFv3 Intra-Area-TE-LSA [RFC5329]. The format of the link attribute TLVs that have been defined for RSVP-TE applications will be kept unchanged even when they are used for non-RSVP-TE applications. Unique code points are allocated for these link attribute TLVs from the OSPFv2 Extended Link TLV Sub-TLV Registry [RFC7684] and from the OSPFv3 Extended LSA Sub-TLV Registry [RFC8362], as specified in Section 14. 5. Advertisement of Application Specific Values @@ -224,93 +224,93 @@ Extended Link TLV and OSPFv3 Router-Link TLV. It has the following format: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | SABM Length | UDABM Length | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - | Standard Application Identifier Bit-Mask | + | Standard Application Identifier Bit Mask | +- -+ | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - | User Defined Application Identifier Bit-Mask | + | User Defined Application Identifier Bit Mask | +- -+ | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Link Attribute sub-sub-TLVs | +- -+ | ... | where: Type: 10 (OSPFv2), 11 (OSPFv3) Length: variable - SABM Length: Standard Application Identifier Bit-Mask Length in - octets. The legal values are 0, 4 or 8. If the Standard - Application Bit-Mask is not present, the Standard Application Bit- - Mask Length MUST be set to 0. + SABM Length: Standard Application Identifier Bit Mask Length in + octets. The value MUST be 0, 4 or 8. If the Standard Application + Bit Mask is not present, the Standard Application Bit Mask Length + MUST be set to 0. - UDABM Length: User Defined Application Identifier Bit-Mask Length + UDABM Length: User Defined Application Identifier Bit Mask Length in octets. The legal values are 0, 4 or 8. If the User Defined - Application Bit-Mask is not present, the User Defined Application - Bit-Mask Length MUST be set to 0. + Application Bit Mask is not present, the User Defined Application + Bit Mask 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 defined in [I-D.ietf-isis-te-app]. The bits are repeated here for informational purpose: Bit-0 (R-bit): RSVP-TE Bit-1 (S-bit): Segment Routing TE Bit-2 (F-bit): Loop Free Alternate (LFA). Includes all LFA types - User Defined Application Identifier Bit-Mask: Optional set of + User Defined Application Identifier Bit Mask: 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- TLV MUST be ignored by the receiver. Standard Application Identifier Bits are defined/sent starting with Bit 0. Undefined bits MUST be 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 not supported by an implementation MUST be ignored on receipt. User Defined Application Identifier Bits have no relationship to Standard Application Identifier Bits and are NOT managed by IANA or any other standards body. It is recommended that bits are used starting with Bit 0 so as to minimize the number of octets required to advertise all UDAs. If the link attribute advertisement is limited to be used by a - specific set of applications, corresponding Bit-Masks MUST be present + specific set of applications, corresponding Bit Masks MUST be present and application specific bit(s) MUST be set for all applications that use the link attributes advertised in the ASLA sub-TLV. - Application Bit-Masks apply to all link attributes that support + Application Bit Masks apply to all link attributes that support application specific values and are advertised in the ASLA sub-TLV. - The advantage of not making the Application Bit-Masks part of the + The advantage of not making the Application Bit Masks part of the attribute advertisement itself is that the format of any previously defined link attributes can be kept and reused when advertising them in the ASLA sub-TLV. If the same attribute is advertised in more than single ASLA sub-TLVs - with the application listed in the Application Bit-Masks, the + with the application listed in the Application Bit Masks, the application SHOULD use the first instance of advertisement and ignore any subsequent advertisements of that attribute. This document defines the initial set of link attributes that MUST use the ASLA sub-TLV if advertised in the OSPFv2 Extended Link TLV or in the OSPFv3 Router-Link TLV. Documents which define new link attributes MUST state whether the new attributes support application specific values and as such MUST be advertised in an ASLA sub-TLV. The link attributes that MUST be advertised in ASLA sub-TLVs are: @@ -449,22 +449,24 @@ 8. Considerations for Extended TE Metrics [RFC7471] defines a number of dynamic performance metrics associated with a link. It is conceivable that such metrics could be measured specific to traffic associated with a specific application. Therefore this document includes support for advertising these link attributes specific to a given application. However, in practice it may well be more practical to have these metrics reflect the performance of all traffic on the link regardless of application. In such cases, advertisements for these attributes can be associated - with all of the applications utilizing that link, for example, by - listing all applications in the Application Bit-Mask. + with all of the applications utilizing that link. This can be done + either by explicitly specifying the applications in the Application + Identifier Bit Mask or by using a zero length Application Identifier + Bit Mask. 9. Local Interface IPv6 Address Sub-TLV The Local Interface IPv6 Address Sub-TLV is an application independent attribute of the link that is defined in [RFC5329]. Because it is an application independent attribute, it MUST NOT be advertised in the ASLA sub-TLV. Instead, it MAY be advertised as a sub-TLV of the OSPFv3 E-Router-LSA Router-Link TLV [RFC8362]. To advertise the Local Interface IPv6 Address Sub-TLV in the OSPFv3 @@ -529,21 +531,21 @@ 12. Deployment Considerations 12.1. Use of Legacy RSVP-TE LSA Advertisements Bit Identifiers for Standard Applications are defined in Section 5. All of the identifiers defined in this document are associated with applications which were already deployed in some networks prior to the writing of this document. Therefore, such applications have been deployed using the RSVP-TE LSA advertisements. The Standard - Applications defined in this document MAY continue to use RSVP-TE LSA + Applications defined in this document may continue to use RSVP-TE LSA advertisements for a given link so long as at least one of the following conditions is true: The application is RSVP-TE The application is SRTE or LFA and RSVP-TE is not deployed anywhere in the network The application is SRTE or LFA, RSVP-TE is deployed in the network, and both the set of links on which SRTE and/or LFA @@ -791,21 +793,21 @@ Thanks to Alvaro Retana for his detailed review and comments. 17. References 17.1. Normative References [I-D.ietf-isis-te-app] Ginsberg, L., Psenak, P., Previdi, S., Henderickx, W., and J. Drake, "IS-IS TE Attributes per application", draft- - ietf-isis-te-app-12 (work in progress), March 2020. + ietf-isis-te-app-13 (work in progress), May 2020. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC2328] Moy, J., "OSPF Version 2", STD 54, RFC 2328, DOI 10.17487/RFC2328, April 1998, . @@ -850,22 +852,22 @@ [RFC8362] Lindem, A., Roy, A., Goethals, D., Reddy Vallem, V., and F. Baker, "OSPFv3 Link State Advertisement (LSA) Extensibility", RFC 8362, DOI 10.17487/RFC8362, April 2018, . 17.2. Informative References [I-D.ietf-spring-segment-routing-policy] Filsfils, C., Sivabalan, S., Voyer, D., Bogdanov, A., and P. Mattes, "Segment Routing Policy Architecture", draft- - ietf-spring-segment-routing-policy-06 (work in progress), - December 2019. + ietf-spring-segment-routing-policy-07 (work in progress), + May 2020. [RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V., and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP Tunnels", RFC 3209, DOI 10.17487/RFC3209, December 2001, . [RFC4552] Gupta, M. and N. Melam, "Authentication/Confidentiality for OSPFv3", RFC 4552, DOI 10.17487/RFC4552, June 2006, .