Transparent Interconnection of Lots of Links (TRILL) Use of IS-IS

Abstract

The IETF Transparent Interconnection of Lots of Links (TRILL) protocol provides optimal pair-wise data frame forwarding without configuration in multi-hop networks with arbitrary topology and link technology; it also provides support for multipathing of both unicast and multicast traffic. This document specifies the data formats and code points for the IS-IS extensions to support TRILL. These data formats and code points may also be used by technologies other than TRILL. This document obsoletes RFC 6326.

Transparent Interconnection of Lots of Links (TRILL): RBridge Channel Header Extension

“…(Both the Port ID of the port on which a TRILL Hello is sent and the nickname of the sending TRILL switch appear in the Special VLANs and Flags sub-TLV [RFC7176] in TRILL IS-IS Hellos.) The resulting MAC address has the Local bit on and the Group bit off [RFC7042].…”

Transparent Interconnection of Lots of Links (TRILL): Using Data Labels for Tree Selection for Multi-Destination Data

“…The Routing Bridge (RBridge) having the highest tree root priority announces the total number of trees that should be computed for the campus. It may also specify the list of trees that RBridges need to compute using the Tree Identifiers (TREE-RT-IDs) sub-TLV [RFC7176]. Every RBridge can specify the trees it will use for multi-destination TRILL Data packets it originates in the Trees Used Identifiers (TREE-USE-IDs) sub-TLV [RFC7176], and the VLANs or Fine-Grained Labels (FGLs) [RFC7172] it is interested in are specified in Interested VLANs and/or Interested Labels sub-TLVs [RFC7176].…”

“…It may also specify the list of trees that RBridges need to compute using the Tree Identifiers (TREE-RT-IDs) sub-TLV [RFC7176]. Every RBridge can specify the trees it will use for multi-destination TRILL Data packets it originates in the Trees Used Identifiers (TREE-USE-IDs) sub-TLV [RFC7176], and the VLANs or Fine-Grained Labels (FGLs) [RFC7172] it is interested in are specified in Interested VLANs and/or Interested Labels sub-TLVs [RFC7176]. It is suggested that by default the ingress RBridge uses the distribution tree whose root is the closest [RFC6325].…”

“…o Group Sub-Sub-TLVs: Zero or more of the TLV structures that are allowed as sub-TLVs of the Group Address (GADDR) TLV [RFC7176]. Each such TLV structure specifies a multicast group and either a VLAN or FGL.…”

“…The highest-priority tree root RBridge MUST include all the necessary tree-related sub-TLVs defined in [RFC7176] as usual in its E-L1FS FS-LSP and MAY include the TREE-VLANs APPsub-TLV and/or the TREE-FGLs APPsub-TLV in its E-L1FS FS-LSP [RFC7780]. In this way, it MAY indicate that each VLAN and/or FGL is only allowed on one or some other number of trees less than the number of trees being calculated in the campus in order to save table space in the fast-path forwarding hardware.…”