|Internet-Draft||Advertise Node Ix||January 2023|
|Chen, et al.||Expires 16 July 2023||[Page]|
- Network Working Group
- Intended Status:
- Standards Track
IGP Extensions for Advertising Node Index
This document describes OSPF and IS-IS extensions for distributing the node index configured on a node.¶
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here.¶
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When the nodes in a network are numbered or indexed from 1 to the number of the nodes, an efficient stateless multicast along the shortest paths to the egresses of a P2MP tree can be achieved using the node indices of the egresses.¶
This document proposes OSPF and IS-IS extensions for distributing the node index configured on a node to support the best effort stateless multicast. When a controller such as PCE as a controller has the node indexes, it can send the P2MP tree encoded in the node indexes to the ingress of the tree.¶
This section describes extensions to OSPF for distributing the node index configured on a node. The node index of a node MUST be unique in a network. This is like the identifier (ID) of the node.¶
[RFC7770] defines the Router Information (RI) Link state Advertisement (LSA). The RI LSA is used to advertise Optional Router Information using Router Information LSA TLVs. A new Router Information LSA TLV, called Node Index TLV, is defined to carry the Node Index configured on the node originating the RI LSA. The Node Index TLV has the following format:¶
This TLV is optional. It is applicable to both OSPFv2 and OSPFv3. For advertising a node index, the area-scoped RI LSA including a Node Index TLV is used.¶
This section describes an extension to IS-IS for distributing the Node Index configured on a node.¶
[RFC7981] defines the IS-IS Router CAPABILITY TLV to advertise Router Information. The TLV includes multiple sub-TLVs. A new Node Index sub-TLV to be included in the TLV, is defined to carry the Node Index configured on the node originating the TLV in its LSP. This sub-TLV has the following format:¶
This sub-TLV is optional. For advertising a node index, the area-scoped LSP including a Node Index sub-TLV in an IS-IS Router CAPABILITY TLV is used.¶
+==============+===================+=====================+ | Value | Description | reference | +==============+===================+=====================+ | TBD1 | Node Index | This document | +--------------+-------------------+---------------------+¶
+==============+===================+=====================+ | Value | Description | reference | +==============+===================+=====================+ | TBD2 | Node Index | This document | +--------------+-------------------+---------------------+¶
- Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, , <https://www.rfc-editor.org/info/rfc2119>.
- Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA Considerations Section in RFCs", RFC 5226, DOI 10.17487/RFC5226, , <https://www.rfc-editor.org/info/rfc5226>.
- Lindem, A., Ed., Shen, N., Vasseur, JP., Aggarwal, R., and S. Shaffer, "Extensions to OSPF for Advertising Optional Router Capabilities", RFC 7770, DOI 10.17487/RFC7770, , <https://www.rfc-editor.org/info/rfc7770>.
- Ginsberg, L., Previdi, S., and M. Chen, "IS-IS Extensions for Advertising Router Information", RFC 7981, DOI 10.17487/RFC7981, , <https://www.rfc-editor.org/info/rfc7981>.
- Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, , <https://www.rfc-editor.org/info/rfc8174>.
- Berger, L., Bryskin, I., Zinin, A., and R. Coltun, "The OSPF Opaque LSA Option", RFC 5250, DOI 10.17487/RFC5250, , <https://www.rfc-editor.org/info/rfc5250>.