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| author | Thomas Voss <mail@thomasvoss.com> | 2024-11-27 20:54:24 +0100 |
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| committer | Thomas Voss <mail@thomasvoss.com> | 2024-11-27 20:54:24 +0100 |
| commit | 4bfd864f10b68b71482b35c818559068ef8d5797 (patch) | |
| tree | e3989f47a7994642eb325063d46e8f08ffa681dc /doc/rfc/rfc7176.txt | |
| parent | ea76e11061bda059ae9f9ad130a9895cc85607db (diff) | |
doc: Add RFC documents
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diff --git a/doc/rfc/rfc7176.txt b/doc/rfc/rfc7176.txt new file mode 100644 index 0000000..bc7763f --- /dev/null +++ b/doc/rfc/rfc7176.txt @@ -0,0 +1,2523 @@ + + + + + + +Internet Engineering Task Force (IETF) D. Eastlake 3rd +Request for Comments: 7176 Huawei +Obsoletes: 6326 T. Senevirathne +Category: Standards Track Cisco +ISSN: 2070-1721 A. Ghanwani + Dell + D. Dutt + Cumulus Networks + A. Banerjee + Insieme Networks + May 2014 + + + 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. + +Status of This Memo + + This is an Internet Standards Track document. + + This document is a product of the Internet Engineering Task Force + (IETF). It represents the consensus of the IETF community. It has + received public review and has been approved for publication by the + Internet Engineering Steering Group (IESG). Further information on + Internet Standards is available in Section 2 of RFC 5741. + + Information about the current status of this document, any errata, + and how to provide feedback on it may be obtained at + http://www.rfc-editor.org/info/rfc7176. + + + + + + + + + + + + +Eastlake, et al. Standards Track [Page 1] + +RFC 7176 TRILL Use of IS-IS May 2014 + + +Copyright Notice + + Copyright (c) 2014 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 + (http://trustee.ietf.org/license-info) in effect on the date of + publication of this document. Please review these documents + carefully, as they describe your rights and restrictions with respect + to this document. Code Components extracted from this document must + include Simplified BSD License text as described in Section 4.e of + the Trust Legal Provisions and are provided without warranty as + described in the Simplified BSD License. + +Table of Contents + + 1. Introduction ....................................................3 + 1.1. Conventions Used in This Document ..........................4 + 2. TLV and Sub-TLV Extensions to IS-IS for TRILL ...................4 + 2.1. Group Address TLV ..........................................5 + 2.1.1. Group MAC Address Sub-TLV ...........................5 + 2.1.2. Group IPv4 Address Sub-TLV ..........................7 + 2.1.3. Group IPv6 Address Sub-TLV ..........................8 + 2.1.4. Group Labeled MAC Address Sub-TLV ...................9 + 2.1.5. Group Labeled IPv4 Address Sub-TLV .................10 + 2.1.6. Group Labeled IPv6 Address Sub-TLV .................11 + 2.2. Multi-Topology-Aware Port Capability Sub-TLVs .............12 + 2.2.1. Special VLANs and Flags Sub-TLV ....................12 + 2.2.2. Enabled-VLANs Sub-TLV ..............................13 + 2.2.3. Appointed Forwarders Sub-TLV .......................14 + 2.2.4. Port TRILL Version Sub-TLV .........................15 + 2.2.5. VLANs Appointed Sub-TLV ............................17 + 2.3. Sub-TLVs of the Router Capability and MT-Capability TLVs ..17 + 2.3.1. TRILL Version Sub-TLV ..............................18 + 2.3.2. Nickname Sub-TLV ...................................19 + 2.3.3. Trees Sub-TLV ......................................20 + 2.3.4. Tree Identifiers Sub-TLV ...........................20 + 2.3.5. Trees Used Identifiers Sub-TLV .....................21 + 2.3.6. Interested VLANs and Spanning Tree Roots Sub-TLV ...22 + 2.3.7. VLAN Group Sub-TLV .................................24 + 2.3.8. Interested Labels and Spanning Tree Roots Sub-TLV ..25 + 2.3.9. RBridge Channel Protocols Sub-TLV ..................27 + 2.3.10. Affinity Sub-TLV ..................................29 + 2.3.11. Label Group Sub-TLV ...............................30 + 2.4. MTU Sub-TLV for Extended Reachability and MT-ISN TLVs .....31 + 2.5. TRILL Neighbor TLV ........................................31 + 3. MTU PDUs .......................................................33 + + + +Eastlake, et al. Standards Track [Page 2] + +RFC 7176 TRILL Use of IS-IS May 2014 + + + 4. Use of Existing PDUs and TLVs ..................................35 + 4.1. TRILL IIH PDUs ............................................35 + 4.2. Area Address ..............................................35 + 4.3. Protocols Supported .......................................35 + 4.4. Link State PDUs (LSPs) ....................................35 + 4.5. Originating LSP Buffer Size ...............................36 + 5. IANA Considerations ............................................36 + 5.1. TLVs ......................................................36 + 5.2. Sub-TLVs ..................................................36 + 5.3. PDUs ......................................................38 + 5.4. Reserved and Capability Bits ..............................38 + 5.5. TRILL Neighbor Record Flags ...............................39 + 6. Security Considerations ........................................39 + 7. Changes from RFC 6326 ..........................................39 + 8. References .....................................................41 + 8.1. Normative References ......................................41 + 8.2. Informative References ....................................43 + 9. Acknowledgements ...............................................44 + +1. Introduction + + The IETF Transparent Interconnection of Lots of Links (TRILL) + protocol [RFC6325] [RFC7177] provides transparent forwarding in + multi-hop networks with arbitrary topology and link technologies + using a header with a hop count and link-state routing. TRILL + provides optimal pair-wise forwarding without configuration, safe + forwarding even during periods of temporary loops, and support for + multipathing of both unicast and multicast traffic. Intermediate + Systems (ISs) implementing TRILL are called Routing Bridges + (RBridges) or TRILL Switches. + + This document, in conjunction with [RFC6165], specifies the data + formats and code points for the IS-IS [ISO-10589] [RFC1195] + extensions to support TRILL. These data formats and code points may + also be used by technologies other than TRILL. + + This document obsoletes [RFC6326], which generally corresponded to + the base TRILL protocol [RFC6325]. There has been substantial + development of TRILL since the publication of those documents. The + main changes from [RFC6326] are summarized below, and a full list is + given in Section 7. + + 1. Added multicast group announcements by IPv4 and IPv6 address. + + 2. Added facilities for announcing capabilities supported. + + 3. Added a tree affinity sub-TLV whereby ISs can request + distribution tree association. + + + +Eastlake, et al. Standards Track [Page 3] + +RFC 7176 TRILL Use of IS-IS May 2014 + + + 4. Added multi-topology support. + + 5. Added control-plane support for TRILL Data frame fine-grained + labels. This support is independent of the data-plane + representation. + + 6. Fixed the verified erratum [Err2869] in [RFC6326]. + + Changes herein to TLVs and sub-TLVs specified in [RFC6326] are + backward compatible. + +1.1. Conventions Used in This Document + + The terminology and acronyms defined in [RFC6325] are used herein + with the same meaning. + + Additional acronyms and phrases used in this document are: + + BVL - Bit Vector Length + + BVO - Bit Vector Offset + + IIH - IS-IS Hello + + IS - Intermediate System. For this document, all relevant + intermediate systems are RBridges [RFC6325]. + + MAC - Media Access Control + + MT - Multi-Topology + + NLPID - Network Layer Protocol Identifier + + SNPA - Subnetwork Point of Attachment (MAC Address) + + 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]. + +2. TLV and Sub-TLV Extensions to IS-IS for TRILL + + This section, in conjunction with [RFC6165], specifies the data + formats and code points for the TLVs and sub-TLVs for IS-IS to + support the IETF TRILL protocol. Information as to the number of + occurrences allowed, such as for a TLV in a PDU or set of PDUs or for + a sub-TLV in a TLV, is summarized in Section 5. + + + + + +Eastlake, et al. Standards Track [Page 4] + +RFC 7176 TRILL Use of IS-IS May 2014 + + +2.1. Group Address TLV + + The Group Address (GADDR) TLV, IS-IS TLV type 142, is carried in an + LSP PDU and carries sub-TLVs that in turn advertise multicast group + listeners. The sub-TLVs that advertise listeners are specified + below. The sub-TLVs under GADDR constitute a new series of sub-TLV + types (see Section 5.2). + + GADDR has the following format: + + +-+-+-+-+-+-+-+-+ + |Type=GADDR-TLV | (1 byte) + +-+-+-+-+-+-+-+-+ + | Length | (1 byte) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-... + | sub-TLVs... + +-+-+-+-+-+-+-+-+-+-+-+-+-+-... + + o Type: TLV type, set to GADDR-TLV 142. + + o Length: variable depending on the sub-TLVs carried. + + o sub-TLVs: The Group Address TLV value consists of sub-TLVs + formatted as described in [RFC5305]. + +2.1.1. Group MAC Address Sub-TLV + + The Group MAC Address (GMAC-ADDR) sub-TLV is sub-TLV type number 1 + within the GADDR TLV. In TRILL, it is used to advertise multicast + listeners by MAC address as specified in Section 4.5.5 of [RFC6325]. + It has the following format: + + + + + + + + + + + + + + + + + + + + +Eastlake, et al. Standards Track [Page 5] + +RFC 7176 TRILL Use of IS-IS May 2014 + + + +-+-+-+-+-+-+-+-+ + |Type=GMAC-ADDR | (1 byte) + +-+-+-+-+-+-+-+-+ + | Length | (1 byte) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | RESV | Topology-ID | (2 bytes) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | RESV | VLAN ID | (2 bytes) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + |Num Group Recs | (1 byte) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | GROUP RECORDS (1) | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | GROUP RECORDS (2) | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | ................. | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | GROUP RECORDS (N) | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + + where each group record is of the following form with k=6: + + +-+-+-+-+-+-+-+-+ + | Num of Sources| (1 byte) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Group Address (k bytes) | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Source 1 Address (k bytes) | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Source 2 Address (k bytes) | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | ..... | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Source M Address (k bytes) | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + + o Type: GADDR sub-TLV type, set to 1 (GMAC-ADDR). + + o Length: 5 + m + k*n = 5 + m + 6*n, where m is the number of group + records and n is the sum of the number of group and source + addresses. + + o RESV: Reserved. 4-bit fields that MUST be sent as zero and + ignored on receipt. + + o Topology-ID: This field carries a topology ID [RFC5120] or zero if + topologies are not in use. + + + + +Eastlake, et al. Standards Track [Page 6] + +RFC 7176 TRILL Use of IS-IS May 2014 + + + o VLAN ID: This carries the 12-bit VLAN identifier for all + subsequent MAC addresses in this sub-TLV, or the value zero if no + VLAN is specified. + + o Num Group Recs: A 1-byte unsigned integer that is the number of + group records in this sub-TLV. + + o GROUP RECORDS: Each group record carries the number of sources. + If this field is zero, it indicates a listener for (*,G), that is, + a listener not restricted by source. It then has a 6-byte + (48-bit) multicast MAC address followed by 6-byte source MAC + addresses. If the sources do not fit in a single sub-TLV, the + same group address may be repeated with different source addresses + in another sub-TLV of another instance of the Group Address TLV. + + The GMAC-ADDR sub-TLV is carried only within a GADDR TLV. + +2.1.2. Group IPv4 Address Sub-TLV + + The Group IPv4 Address (GIP-ADDR) sub-TLV is IS-IS sub-TLV type 2 + within the GADDR TLV. It has the same format as the Group MAC + Address sub-TLV described in Section 2.1.1 except that k=4. The + fields are as follows: + + o Type: sub-TLV type, set to 2 (GIP-ADDR). + + o Length: 5 + m + k*n = 5 + m + 4*n, where m is the number of group + records and n is the sum of the number of group and source + addresses. + + o Topology-ID: This field carries a topology ID [RFC5120] or zero if + topologies are not in use. + + o RESV: Must be sent as zero on transmission and is ignored on + receipt. + + o VLAN ID: This carries a 12-bit VLAN identifier that is valid for + all subsequent addresses in this sub-TLV, or the value zero if no + VLAN is specified. + + o Num Group Recs: A 1-byte unsigned integer that is the number of + group records in this sub-TLV. + + + + + + + + + +Eastlake, et al. Standards Track [Page 7] + +RFC 7176 TRILL Use of IS-IS May 2014 + + + o GROUP RECORDS: Each group record carries the number of sources. + If this field is zero, it indicates a listener for (*,G), that is, + a listener not restricted by source. It then has a 4-byte + (32-bit) IPv4 Group Address followed by 4-byte source IPv4 + addresses. If the number of sources do not fit in a single sub- + TLV, it is permitted to have the same group address repeated with + different source addresses in another sub-TLV of another instance + of the Group Address TLV. + + The GIP-ADDR sub-TLV is carried only within a GADDR TLV. + +2.1.3. Group IPv6 Address Sub-TLV + + The Group IPv6 Address (GIPV6-ADDR) sub-TLV is IS-IS sub-TLV type 3 + within the GADDR TLV. It has the same format as the Group MAC + Address sub-TLV described in Section 2.1.1 except that k=16. The + fields are as follows: + + o Type: sub-TLV type, set to 3 (GIPV6-ADDR). + + o Length: 5 + m + k*n = 5 + m + 16*n, where m is the number of group + records and n is the sum of the number of group and source + addresses. + + o Topology-Id: This field carries a topology ID [RFC5120] or zero if + topologies are not in use. + + o RESV: Must be sent as zero on transmission and is ignored on + receipt. + + o VLAN ID: This carries a 12-bit VLAN identifier that is valid for + all subsequent addresses in this sub-TLV, or the value zero if no + VLAN is specified. + + o Num Group Recs: A 1-byte unsigned integer that is the number of + group records in this sub-TLV. + + o GROUP RECORDS: Each group record carries the number of sources. + If this field is zero, it indicates a listener for (*,G), that is, + a listener not restricted by source. It then has a 16-byte + (128-bit) IPv6 Group Address followed by 16-byte source IPv6 + addresses. If the number of sources do not fit in a single sub- + TLV, it is permitted to have the same group address repeated with + different source addresses in another sub-TLV of another instance + of the Group Address TLV. + + The GIPV6-ADDR sub-TLV is carried only within a GADDR TLV. + + + + +Eastlake, et al. Standards Track [Page 8] + +RFC 7176 TRILL Use of IS-IS May 2014 + + +2.1.4. Group Labeled MAC Address Sub-TLV + + The GMAC-ADDR sub-TLV of the Group Address (GADDR) TLV specified in + Section 2.1.1 provides for a VLAN ID. The Group Labeled MAC Address + sub-TLV, below, extends this to a fine-grained label. + + +-+-+-+-+-+-+-+-+ + |Type=GLMAC-ADDR| (1 byte) + +-+-+-+-+-+-+-+-+ + | Length | (1 byte) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | RESV | Topology-ID | (2 bytes) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Fine-Grained Label | (3 bytes) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + |Num Group Recs | (1 byte) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | GROUP RECORDS (1) | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | GROUP RECORDS (2) | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | ................. | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | GROUP RECORDS (N) | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + + where each group record is of the following form with k=6: + + +-+-+-+-+-+-+-+-+ + | Num of Sources| (1 byte) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Group Address (k bytes) | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Source 1 Address (k bytes) | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Source 2 Address (k bytes) | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | ..... | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Source M Address (k bytes) | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + + o Type: GADDR sub-TLV type, set to 4 (GLMAC-ADDR). + + o Length: 6 + m + k*n = 6 + m + 6*n, where m is the number of group + records and n is the sum of the number of group and source + addresses. + + + + +Eastlake, et al. Standards Track [Page 9] + +RFC 7176 TRILL Use of IS-IS May 2014 + + + o RESV: Reserved. 4-bit field that MUST be sent as zero and ignored + on receipt. + + o Topology-ID: This field carries a topology ID [RFC5120] or zero if + topologies are not in use. + + o Label: This carries the fine-grained label [RFC7172] identifier + for all subsequent MAC addresses in this sub-TLV, or the value + zero if no label is specified. + + o Num Group Recs: A 1-byte unsigned integer that is the number of + group records in this sub-TLV. + + o GROUP RECORDS: Each group record carries the number of sources. + If this field is zero, it indicates a listener for (*,G), that is, + a listener not restricted by source. It then has a 6-byte + (48-bit) multicast address followed by 6-byte source MAC + addresses. If the sources do not fit in a single sub-TLV, the + same group address may be repeated with different source addresses + in another sub-TLV of another instance of the Group Address TLV. + + The GLMAC-ADDR sub-TLV is carried only within a GADDR TLV. + +2.1.5. Group Labeled IPv4 Address Sub-TLV + + The Group Labeled IPv4 Address (GLIP-ADDR) sub-TLV is IS-IS sub-TLV + type 5 within the GADDR TLV. It has the same format as the Group + Labeled MAC Address sub-TLV described in Section 2.1.4 except that + k=4. The fields are as follows: + + o Type: sub-TLV type, set to 5 (GLIP-ADDR). + + o Length: 6 + m + k*n = 6 + m + 4*n, where m is the number of group + records and n is the sum of the number of group and source + addresses. + + o Topology-ID: This field carries a topology ID [RFC5120] or zero if + topologies are not in use. + + o RESV: Must be sent as zero on transmission and is ignored on + receipt. + + o Label: This carries the fine-grained label [RFC7172] identifier + for all subsequent IPv4 addresses in this sub-TLV, or the value + zero if no label is specified. + + o Num Group Recs: A 1-byte unsigned integer that is the number of + group records in this sub-TLV. + + + +Eastlake, et al. Standards Track [Page 10] + +RFC 7176 TRILL Use of IS-IS May 2014 + + + o GROUP RECORDS: Each group record carries the number of sources. + If this field is zero, it indicates a listener for (*,G), that is, + a listener not restricted by source. It then has a 4-byte + (32-bit) IPv4 Group Address followed by 4-byte source IPv4 + addresses. If the number of sources do not fit in a single sub- + TLV, it is permitted to have the same group address repeated with + different source addresses in another sub-TLV of another instance + of the Group Address TLV. + + The GLIP-ADDR sub-TLV is carried only within a GADDR TLV. + +2.1.6. Group Labeled IPv6 Address Sub-TLV + + The Group Labeled IPv6 Address (GLIPV6-ADDR) sub-TLV is IS-IS sub-TLV + type 6 within the GADDR TLV. It has the same format as the Group + Labeled MAC Address sub-TLV described in Section 2.1.4 except that + k=16. The fields are as follows: + + o Type: sub-TLV type, set to 6 (GLIPV6-ADDR). + + o Length: 6 + m + k*n = 6 + m + 16*n, where m is the number of group + records and n is the sum of the number of group and source + addresses. + + o Topology-Id: This field carries a topology ID [RFC5120] or zero if + topologies are not in use. + + o RESV: Must be sent as zero on transmission and is ignored on + receipt. + + o Label: This carries the fine-grained label [RFC7172] identifier + for all subsequent IPv6 addresses in this sub-TLV, or the value + zero if no label is specified. + + o Num Group Recs: A 1-byte unsigned integer that is the number of + group records in this sub-TLV. + + o GROUP RECORDS: Each group record carries the number of sources. + If this field is zero, it indicates a listener for (*,G), that is, + a listener not restricted by source. It then has a 16-byte + (128-bit) IPv6 Group Address followed by 16-byte source IPv6 + addresses. If the number of sources do not fit in a single sub- + TLV, it is permitted to have the same group address repeated with + different source addresses in another sub-TLV of another instance + of the Group Address TLV. + + The GLIPV6-ADDR sub-TLV is carried only within a GADDR TLV. + + + + +Eastlake, et al. Standards Track [Page 11] + +RFC 7176 TRILL Use of IS-IS May 2014 + + +2.2. Multi-Topology-Aware Port Capability Sub-TLVs + + TRILL makes use of the Multi-Topology-Aware Port Capability TLV (MT- + Port-Cap-TLV) as specified in [RFC6165]. The following subsections + specify the sub-TLVs transported by the MT-Port-Cap-TLV for TRILL. + +2.2.1. Special VLANs and Flags Sub-TLV + + In TRILL, a Special VLANs and Flags (VLAN-FLAGS) sub-TLV is carried + in every IIH PDU. It has the following format: + + +--+--+--+--+--+--+--+--+ + | Type | (1 byte) + +--+--+--+--+--+--+--+--+ + | Length | (1 byte) + +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ + | Port ID | (2 bytes) + +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ + | Sender Nickname | (2 bytes) + +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ + |AF|AC|VM|BY| Outer.VLAN | (2 bytes) + +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ + |TR|R |R |R | Designated-VLAN | (2 bytes) + +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ + + o Type: sub-TLV type, set to MT-Port-Cap-TLV VLAN-FLAGS sub-TLV 1. + + o Length: 8. + + o Port ID: An ID for the port on which the enclosing TRILL IIH PDU + is being sent as specified in [RFC6325], Section 4.4.2. + + o Sender Nickname: If the sending IS is holding any nicknames as + discussed in [RFC6325], Section 3.7, one MUST be included here. + Otherwise, the field is set to zero. This field is to support + intelligent end stations that determine the egress IS (RBridge) + for unicast data through a directory service or the like and that + need a nickname for their first hop to insert as the ingress + nickname to correctly format a TRILL Data frame (see [RFC6325], + Section 4.6.2, point 8). It is also referenced in connection with + the VLANs Appointed Sub-TLV (see Section 2.2.5) and can be used as + the egress on one-hop RBridge Channel messages [RFC7178], for + example, those use for BFD over TRILL [RFC7175]. + + o Outer.VLAN: A copy of the 12-bit outer VLAN ID of the TRILL IIH + frame containing this sub-TLV, as specified in [RFC6325], Section + 4.4.5. + + + + +Eastlake, et al. Standards Track [Page 12] + +RFC 7176 TRILL Use of IS-IS May 2014 + + + o Designated-VLAN: The 12-bit ID of the Designated VLAN for the + link, as specified in [RFC6325], Section 4.2.4.2. + + o AF, AC, VM, BY, and TR: These flag bits have the following + meanings when set to one, as specified in the listed section of + [RFC6325]: + + RFC 6325 + Bit Section Meaning if bit is one + -------------------------------------- + + AF 4.4.2 Originating IS believes it is Appointed + Forwarder for the VLAN and port on which the + containing IIH PDU was sent. + + AC 4.9.1 Originating port configured as an access port + (TRILL traffic disabled). + + VM 4.4.5 VLAN mapping detected on this link. + + BY 4.4.2 Bypass pseudonode. + + TR 4.9.1 Originating port configured as a trunk port + (end-station service disabled). + + o R: Reserved bit. MUST be sent as zero and ignored on receipt. + +2.2.2. Enabled-VLANs Sub-TLV + + The optional Enabled-VLANs sub-TLV specifies the VLANs enabled at the + port of the originating IS on which the containing Hello was sent, as + specified in [RFC6325], Section 4.4.2. It has the following format: + + +-+-+-+-+-+-+-+-+ + | Type | (1 byte) + +-+-+-+-+-+-+-+-+ + | Length | (1 byte) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | RESV | Start VLAN ID | (2 bytes) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | VLAN bit-map.... + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + + o Type: sub-TLV type, set to MT-Port-Cap-TLV Enabled-VLANs sub-TLV + 2. + + o Length: Variable, minimum 3. + + + + +Eastlake, et al. Standards Track [Page 13] + +RFC 7176 TRILL Use of IS-IS May 2014 + + + o RESV: 4 reserved bits that MUST be sent as zero and ignored on + receipt. + + o Start VLAN ID: The 12-bit VLAN ID that is represented by the high- + order bit of the first byte of the VLAN bit-map. + + o VLAN bit-map: The highest-order bit indicates the VLAN equal to + the start VLAN ID, the next highest bit indicates the VLAN equal + to start VLAN ID + 1, continuing to the end of the VLAN bit-map + field. + + If this sub-TLV occurs more than once in a Hello, the set of enabled + VLANs is the union of the sets of VLANs indicated by each of the + Enabled-VLAN sub-TLVs in the Hello. + +2.2.3. Appointed Forwarders Sub-TLV + + The Designated RBridge (DRB) on a link uses the Appointed Forwarders + sub-TLV to inform other ISs on the link that they are the designated + VLAN-x forwarder for one or more ranges of VLAN IDs as specified in + [RFC6439]. It has the following format: + + +-+-+-+-+-+-+-+-+ + | Type | (1 byte) + +-+-+-+-+-+-+-+-+ + | Length | (1 byte) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Appointment Information (1) | (6 bytes) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Appointment Information (2) | (6 bytes) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | ................. | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Appointment Information (N) | (6 bytes) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + + where each appointment is of the form: + + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Appointee Nickname | (2 bytes) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | RESV | Start.VLAN | (2 bytes) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | RESV | End.VLAN | (2 bytes) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + + + + + + +Eastlake, et al. Standards Track [Page 14] + +RFC 7176 TRILL Use of IS-IS May 2014 + + + o Type: sub-TLV type, set to MT-Port-Cap-TLV AppointedFwrdrs sub-TLV + 3. + + o Length: 6*n bytes, where there are n appointments. + + o Appointee Nickname: The nickname of the IS being appointed a + forwarder. + + o RESV: 4 bits that MUST be sent as zero and ignored on receipt. + + o Start.VLAN, End.VLAN: This VLAN ID range is inclusive. Setting + both Start.VLAN and VLAN.end to the same value indicates a range + of one VLAN ID. If Start.VLAN is not equal to VLAN.end and + Start.VLAN is 0x000, the sub-TLV is interpreted as if Start.VLAN + was 0x001. If Start.VLAN is not equal to VLAN.end and VLAN.end is + 0xFFF, the sub-TLV is interpreted as if VLAN.end was 0xFFE. If + VLAN.end is less than Start.VLAN, the sub-TLV is ignored. If both + Start.VLAN and VLAN.end are 0x000 or both are 0xFFF, the sub-TLV + is ignored. The values 0x000 or 0xFFF are not valid VLAN IDs, and + a port cannot be enabled for them. + + An IS's nickname may occur as Appointed Forwarder for multiple VLAN + ranges by occurrences of this sub-TLV within the same or different MT + Port Capability TLVs within an IIH PDU. See [RFC6439]. + +2.2.4. Port TRILL Version Sub-TLV + + The Port TRILL Version (PORT-TRILL-VER) sub-TLV indicates the maximum + version of the TRILL standard supported and the support of optional + hop-by-hop capabilities. By implication, lower versions are also + supported. If this sub-TLV is missing from an IIH, it is assumed + that the originating IS only supports the base version (version zero) + of the protocol [RFC6325] and supports no optional capabilities + indicated by this sub-TLV. + + +-+-+-+-+-+-+-+-+ + | Type | (1 byte) + +-+-+-+-+-+-+-+-+ + | Length | (1 byte) + +-+-+-+-+-+-+-+-+ + | Max-version | (1 byte) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...-+ + | Capabilities and Header Flags Supported | (4 bytes) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...-+-+ + 0 1 3 + 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 0 1 + + + + + +Eastlake, et al. Standards Track [Page 15] + +RFC 7176 TRILL Use of IS-IS May 2014 + + + o Type: MT-Port-Cap-TLV sub-TLV type, set to 7 (PORT-TRILL-VER). + + o Length: 5. + + o Max-version: A one-byte unsigned integer set to the maximum + version supported. + + o Capabilities and Header Flags Supported: A bit vector of 32 bits + numbered 0 through 31 in network order. Bits 3 through 13 + indicate that the corresponding TRILL Header hop-by-hop extended + flags [RFC7179] are supported. Bits 0 through 2 and 14 to 31 are + reserved to indicate support of optional capabilities. A one bit + indicates that the flag or capability is supported by the sending + IS. Bits in this field MUST be set to zero except as permitted + for a capability being advertised or if a hop-by-hop extended + header flag is supported. + + This sub-TLV, if present, MUST occur in an MT-Port-Cap-TLV in a TRILL + IIH. If there is more than one occurrence, the minimum of the + supported versions is assumed to be correct and a capability or + header flag is assumed to be supported only if indicated by all + occurrences. The flags and capabilities for which support can be + indicated in this sub-TLV are disjoint from those in the TRILL-VER + sub-TLV (Section 2.3.1) so they cannot conflict. The flags and + capabilities indicated in this sub-TLV relate to hop-by-hop + processing that can differ between the ports of an IS (RBridge) and + thus must be advertised in IIHs. For example, a capability requiring + cryptographic hardware assist might be supported on some ports and + not others. However, the TRILL version is the same as that in the + PORT-TRILL-VER sub-TLV. An IS, if it is adjacent to the sending IS + of TRILL version sub-TLV(s), uses the TRILL version it received in + PORT-TRILL-VER sub-TLV(s) in preference to that received in TRILL-VER + sub-TLV(s). + + + + + + + + + + + + + + + + + + +Eastlake, et al. Standards Track [Page 16] + +RFC 7176 TRILL Use of IS-IS May 2014 + + +2.2.5. VLANs Appointed Sub-TLV + + The optional VLANs Appointed sub-TLV specifies, for the port of the + originating IS on which the containing Hello was sent, the VLANs for + which it is Appointed Forwarder. This sub-TLV has the following + format: + + +-+-+-+-+-+-+-+-+ + | Type | (1 byte) + +-+-+-+-+-+-+-+-+ + | Length | (1 byte) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | RESV | Start VLAN ID | (2 bytes) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | VLAN bit-map.... + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + + o Type: sub-TLV type, set to MT-Port-Cap-TLV VLANS-Appointed sub-TLV + 8. + + o Length: Variable, minimum 3. + + o RESV: 4 reserved bits that MUST be sent as zero and ignored on + receipt. + + o Start VLAN ID: The 12-bit VLAN ID that is represented by the high- + order bit of the first byte of the VLAN bit-map. + + o VLAN bit-map: The highest-order bit indicates the VLAN equal to + the start VLAN ID, the next highest bit indicates the VLAN equal + to start VLAN ID + 1, continuing to the end of the VLAN bit-map + field. + + If this sub-TLV occurs more than once in a Hello, the originating IS + is declaring that it believes itself to be Appointed Forwarder on the + port on which the enclosing IIH was sent for the union of the sets of + VLANs indicated by each of the VLANs-Appointed sub-TLVs in the Hello. + +2.3. Sub-TLVs of the Router Capability and MT-Capability TLVs + + The Router Capability TLV is specified in [RFC4971] and the MT- + Capability TLV in [RFC6329]. All of the following sub-sections + specify sub-TLVs that can be carried in the Router Capability TLV + (#242) and the MT-Capability TLV (#144) with the same sub-TLV number + for both TLVs. These TLVs are in turn carried only by LSPs. + + + + + + +Eastlake, et al. Standards Track [Page 17] + +RFC 7176 TRILL Use of IS-IS May 2014 + + +2.3.1. TRILL Version Sub-TLV + + The TRILL Version (TRILL-VER) sub-TLV indicates the maximum version + of the TRILL standard supported and the support of optional + capabilities by the originating IS. By implication, lower versions + are also supported. If this sub-TLV is missing, it is assumed that + the originating IS only supports the base version (version zero) of + the protocol [RFC6325], and no optional capabilities indicated by + this sub-TLV are supported. + + +-+-+-+-+-+-+-+-+ + | Type | (1 byte) + +-+-+-+-+-+-+-+-+ + | Length | (1 byte) + +-+-+-+-+-+-+-+-+ + | Max-version | (1 byte) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...-+ + | Capabilities and Header Flags Supported | (4 bytes) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...-+-+ + 0 1 3 + 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 0 1 + + o Type: Router Capability sub-TLV type, set to 13 (TRILL-VER). + + o Length: 5. + + o Max-version: A one-byte unsigned integer set to the maximum + version supported. + + o Capabilities and Header Flags Supported: A bit vector of 32 bits + numbered 0 through 31 in network order. Bits 14 through 31 + indicate that the corresponding TRILL Header extended flags + [RFC7179] are supported. Bits 0 through 13 are reserved to + indicate support of optional capabilities. A one bit indicates + that the originating IS supports the flag or capability. For + example, support of multi-level TRILL IS-IS [MultiLevel]. Bits in + this field MUST be set to zero except as permitted for a + capability being advertised or an extended header flag supported. + + This sub-TLV, if present in a Router Capability TLV, MUST occur in + the LSP number zero for the originating IS. If found in a Router + Capability TLV in other fragments, it is ignored. If there is more + than one occurrence in LSP number zero, the minimum of the supported + versions is assumed to be correct, and an extended header flag or + capability is assumed to be supported only if indicated by all + occurrences. The flags and capabilities for which support can be + indicated in this sub-TLV are disjoint from those in the PORT-TRILL- + VER sub-TLV (Section 2.2.4) so they cannot conflict. However, the + + + +Eastlake, et al. Standards Track [Page 18] + +RFC 7176 TRILL Use of IS-IS May 2014 + + + TRILL version is the same as that in the PORT-TRILL-VER sub-TLV, and + an IS that is adjacent to the originating IS of TRILL-VER sub-TLV(s) + uses the TRILL version it received in PORT-TRILL-VER sub-TLV(s) in + preference to that received in TRILL-VER sub-TLV(s). + + For multi-topology-aware TRILL Switches, the TRILL version and + capabilities announced for the base topology are assumed to apply to + all topologies for which a separate TRILL version announcement does + not occur in an MT-Capability TLV. Such announcements for non-zero + topologies need not occur in fragment zero. + +2.3.2. Nickname Sub-TLV + + The Nickname (NICKNAME) Router Capability sub-TLV carries information + about the nicknames of the originating IS, along with information + about its priority to hold those nicknames and the priority for each + nickname to be a tree root as specified in [RFC6325], Section 3.7.3. + Multiple instances of this sub-TLV may occur. + + +-+-+-+-+-+-+-+-+ + |Type = NICKNAME| (1 byte) + +-+-+-+-+-+-+-+-+ + | Length | (1 byte) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | NICKNAME RECORDS (1) | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | NICKNAME RECORDS (2) | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | ................. | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | NICKNAME RECORDS (N) | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + + where each nickname record is of the form: + + +-+-+-+-+-+-+-+-+ + | Nickname.Pri | (1 byte) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Tree Root Priority | (2 byte) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Nickname | (2 bytes) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + + o Type: Router Capability and MT-Capability sub-TLV type, set to 6 + (NICKNAME). + + o Length: 5*n, where n is the number of nickname records present. + + + + +Eastlake, et al. Standards Track [Page 19] + +RFC 7176 TRILL Use of IS-IS May 2014 + + + o Nickname.Pri: An 8-bit unsigned integer priority to hold a + nickname as specified in Section 3.7.3 of [RFC6325]. + + o Tree Root Priority: This is an unsigned 16-bit integer priority to + be a tree root as specified in Section 4.5 of [RFC6325]. + + o Nickname: This is an unsigned 16-bit integer as specified in + Section 3.7 of [RFC6325]. + +2.3.3. Trees Sub-TLV + + Each IS providing TRILL service uses the TREES sub-TLV to announce + three numbers related to the computation of distribution trees as + specified in Section 4.5 of [RFC6325]. Its format is as follows: + + +-+-+-+-+-+-+-+-+ + |Type = TREES | (1 byte) + +-+-+-+-+-+-+-+-+ + | Length | (1 byte) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Number of trees to compute | (2 byte) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Maximum trees able to compute | (2 byte) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Number of trees to use | (2 byte) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + + o Type: Router Capability and MT-Capability sub-TLV type, set to 7 + (TREES). + + o Length: 6. + + o Number of trees to compute: An unsigned 16-bit integer as + specified in Section 4.5 of [RFC6325]. + + o Maximum trees able to compute: An unsigned 16-bit integer as + specified in Section 4.5 of [RFC6325]. + + o Number of trees to use: An unsigned 16-bit integer as specified in + Section 4.5 of [RFC6325]. + +2.3.4. Tree Identifiers Sub-TLV + + The Tree Identifiers (TREE-RT-IDs) sub-TLV is an ordered list of + nicknames. When originated by the IS that has the highest priority + to be a tree root, it lists the distribution trees that the other ISs + are required to compute as specified in Section 4.5 of [RFC6325]. If + + + + +Eastlake, et al. Standards Track [Page 20] + +RFC 7176 TRILL Use of IS-IS May 2014 + + + this information is spread across multiple sub-TLVs, the starting + tree number is used to allow the ordered lists to be correctly + concatenated. The sub-TLV format is as follows: + + +-+-+-+-+-+-+-+-+ + |Type=TREE-RT-IDs| (1 byte) + +-+-+-+-+-+-+-+-+ + | Length | (1 byte) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + |Starting Tree Number | (2 bytes) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Nickname (K-th root) | (2 bytes) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Nickname (K+1 - th root) | (2 bytes) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Nickname (...) | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + + o Type: Router Capability and MT-Capability sub-TLV type, set to 8 + (TREE-RT-IDs). + + o Length: 2 + 2*n, where n is the number of nicknames listed. + + o Starting Tree Number: This identifies the starting tree number of + the nicknames that are trees for the domain. This is set to 1 for + the sub-TLV containing the first list. Other Tree-Identifiers + sub-TLVs will have the number of the starting list they contain. + In the event the same tree identifier can be computed from two + such sub-TLVs and they are different, then it is assumed that this + is a transient condition that will get cleared. During this + transient time, such a tree SHOULD NOT be computed unless such + computation is indicated by all relevant sub-TLVs present. + + o Nickname: The nickname at which a distribution tree is rooted. + +2.3.5. Trees Used Identifiers Sub-TLV + + This Router Capability sub-TLV has the same structure as the Tree + Identifiers sub-TLV specified in Section 2.3.4. The only difference + is that its sub-TLV type is set to 9 (TREE-USE-IDs), and the trees + listed are those that the originating IS wishes to use as specified + in [RFC6325], Section 4.5. + + + + + + + + + +Eastlake, et al. Standards Track [Page 21] + +RFC 7176 TRILL Use of IS-IS May 2014 + + +2.3.6. Interested VLANs and Spanning Tree Roots Sub-TLV + + The value of this sub-TLV consists of a VLAN range and information in + common to all of the VLANs in the range for the originating IS. This + information consists of flags, a variable length list of spanning + tree root bridge IDs, and an Appointed Forwarder status lost counter, + all as specified in the sections of [RFC6325] listed with the + respective information items below. + + In the set of LSPs originated by an IS, the union of the VLAN ranges + in all occurrences of this sub-TLV MUST be the set of VLANs for which + the originating IS is Appointed Forwarder on at least one port, and + the VLAN ranges in multiple VLANs sub-TLVs for an IS MUST NOT overlap + unless the information provided about a VLAN is the same in every + instance. However, as a transient state, these conditions may be + violated. If a VLAN is not listed in any INT-VLAN sub-TLV for an IS, + that IS is assumed to be uninterested in receiving traffic for that + VLAN. If a VLAN appears in more than one INT-VLAN sub-TLV for an IS + with different information in the different instances, the following + apply: + + - If those sub-TLVs provide different nicknames, it is unspecified + which nickname takes precedence. + - The largest Appointed Forwarder status lost counter, using serial + number arithmetic [RFC1982], is used. + - The originating IS is assumed to be attached to a multicast IPv4 + router for that VLAN if any of the INT-VLAN sub-TLVs assert that + it is so connected and similarly for IPv6 multicast router + attachment. + - The root bridge lists from all of the instances of the VLAN for + the originating IS are merged. + + To minimize such occurrences, wherever possible, an implementation + SHOULD advertise the update to an interested VLAN and Spanning Tree + Roots sub-TLV in the same LSP fragment as the advertisement that it + replaces. Where this is not possible, the two affected LSP fragments + should be flooded as an atomic action. An IS that receives an update + to an existing interested VLAN and Spanning Tree Roots sub-TLV can + minimize the potential disruption associated with the update by + employing a hold-down timer prior to processing the update so as to + allow for the receipt of multiple LSP fragments associated with the + same update prior to beginning processing. + + + + + + + + + +Eastlake, et al. Standards Track [Page 22] + +RFC 7176 TRILL Use of IS-IS May 2014 + + + The sub-TLV layout is as follows: + + +-+-+-+-+-+-+-+-+ + |Type = INT-VLAN| (1 byte) + +-+-+-+-+-+-+-+-+ + | Length | (1 byte) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Nickname | (2 bytes) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+...+-+-+-+ + | Interested VLANS | (4 bytes) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+...+-+-+-+ + | Appointed Forwarder Status Lost Counter | (4 bytes) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+...+ + | Root Bridges | (6*n bytes) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+...+-+-+ + + o Type: Router Capability and MT-Capability sub-TLV type, set to 10 + (INT-VLAN). + + o Length: 10 + 6*n, where n is the number of root bridge IDs. + + o Nickname: As specified in [RFC6325], Section 4.2.4.4, this field + may be used to associate a nickname held by the originating IS + with the VLAN range indicated. When not used in this way, it is + set to zero. + + o Interested VLANS: The Interested VLANs field is formatted as shown + below. + + 0 1 2 3 4 - 15 16 - 19 20 - 31 + +----+----+----+----+------------+----------+------------+ + | M4 | M6 | R | R | VLAN.start | RESV | VLAN.end | + +----+----+----+----+------------+----------+------------+ + + - M4, M6: These bits indicate, respectively, that there is an + IPv4 or IPv6 multicast router on a link for which the + originating IS is Appointed Forwarder for every VLAN in the + indicated range as specified in [RFC6325], Section 4.2.4.4, + item 5.1. + + - R, RESV: These reserved bits MUST be sent as zero and are + ignored on receipt. + + - VLAN.start and VLAN.end: This VLAN ID range is inclusive. + Setting both VLAN.start and VLAN.end to the same value + indicates a range of one VLAN ID. If VLAN.start is not equal + to VLAN.end and VLAN.start is 0x000, the sub-TLV is interpreted + as if VLAN.start was 0x001. If VLAN.start is not equal to + + + +Eastlake, et al. Standards Track [Page 23] + +RFC 7176 TRILL Use of IS-IS May 2014 + + + VLAN.end and VLAN.end is 0xFFF, the sub-TLV is interpreted as + if VLAN.end was 0xFFE. If VLAN.end is less than VLAN.start, + the sub-TLV is ignored. If both VLAN.start and VLAN.end are + 0x000 or both are 0xFFF, the sub-TLV is ignored. The values + 0x000 or 0xFFF are not valid VLAN IDs, and a port cannot be + enabled for them. + + o Appointed Forwarder Status Lost Counter: This is a count of how + many times a port that was Appointed Forwarder for the VLANs in + the range given has lost the status of being an Appointed + Forwarder for some port as discussed in Section 4.8.3 of + [RFC6325]. It is initialized to zero at an IS when the zeroth LSP + sequence number is initialized. No special action need be taken + at rollover; the counter just wraps around. + + o Root Bridges: The list of zero or more spanning tree root bridge + IDs is the set of root bridge IDs seen for all ports for which the + IS is Appointed Forwarder for the VLANs in the specified range as + discussed in [RFC6325], Section 4.9.3.2. While, of course, at + most one spanning tree root could be seen on any particular port, + there may be multiple ports in the same VLANs connected to + different bridged LANs with different spanning tree roots. + + An INT-VLAN sub-TLV asserts that the information provided (multicast + router attachment, Appointed Forwarder status lost counter, and root + bridges) is the same for all VLANs in the range specified. If this + is not the case, the range MUST be split into subranges meeting this + criteria. It is always safe to use sub-TLVs with a "range" of one + VLAN ID, but this may be too verbose. + +2.3.7. VLAN Group Sub-TLV + + The VLAN Group sub-TLV consists of two or more VLAN IDs as specified + in [RFC6325], Section 4.8.4. This sub-TLV indicates that shared VLAN + learning is occurring at the originating IS between the listed VLANs. + It is structured as follows: + + +-+-+-+-+-+-+-+-+ + |Type=VLAN-GROUP| (1 byte) + +-+-+-+-+-+-+-+-+ + | Length | (1 byte) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | RESV | Primary VLAN ID | (2 bytes) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | RESV | Secondary VLAN ID | (2 bytes) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | more Secondary VLAN IDs ... (2 bytes each) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + + + +Eastlake, et al. Standards Track [Page 24] + +RFC 7176 TRILL Use of IS-IS May 2014 + + + o Type: Router Capability and MT-Capability sub-TLV type, set to 14 + (VLAN-GROUP). + + o Length: 4 + 2*n, where n is the number of secondary VLAN ID fields + beyond the first. n MAY be zero. + + o RESV: a 4-bit field that MUST be sent as zero and ignored on + receipt. + + o Primary VLAN ID: This identifies the primary VLAN ID. + + o Secondary VLAN ID: This identifies a secondary VLAN in the VLAN + Group. + + o more Secondary VLAN IDs: zero or more byte pairs, each with the + top 4 bits as a RESV field and the low 12 bits as a VLAN ID. + +2.3.8. Interested Labels and Spanning Tree Roots Sub-TLV + + An IS that can handle fine-grained labeling [RFC7172] announces its + fine-grained label connectivity and related information in the + Interested Labels and Spanning Tree Roots sub-TLV (INT-LABEL). It is + a variation of the Interested VLANs and Spanning Tree Roots sub-TLV + (INT-VLAN) and is structured as follows. + + +-+-+-+-+-+-+-+-+ + |Type=INT-LABEL | (1 byte) + +-+-+-+-+-+-+-+-+ + | Length | (1 byte) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Nickname | (2 bytes) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+...+-+-+-+-+ + | Interested Labels | (7 bytes) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+...+-+-+-+-+ + | Appointed Forwarder Status Lost Counter | (4 bytes) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+...+-+-+ + | Root Bridges | (6*n bytes) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+...+-+-+ + + o Type: Router Capability and MT-Capability sub-TLV type, set to 15 + (INT-LABEL). + + o Length: 11 + 6*n, where n is the number of root bridge IDs. + + o Nickname: This field may be used to associate a nickname held by + the originating IS with the Interested Labels indicated. When not + used in this way, it is set to zero. + + + + +Eastlake, et al. Standards Track [Page 25] + +RFC 7176 TRILL Use of IS-IS May 2014 + + + o Interested Labels: The Interested Labels field is seven bytes long + and formatted as shown below. + + 0 1 2 3 4 5 6 7 + +--+--+--+--+--+--+--+--+ + |M4|M6|BM| R| R| R| R| R| . . + +--+--+--+--+--+--+--+--+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Label.start - 24 bits | + +--+--+--+--+--+--+--+--+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Label.end or bit-map - 24 bits | + +--+--+--+--+--+--+--+--+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + 0 1 2 + 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 + + - M4, M6: These bits indicate, respectively, that there is an + IPv4 or IPv6 multicast router on a link to which the + originating IS is Appointed Forwarder for the VLAN + corresponding to every label in the indicated range. + + - BM: If the BM (bit-map) bit is zero, the last three bytes of + the Interested Labels is a Label.end label number. If the BM + bit is one, those bytes are a bit-map as described below. + + - R: These reserved bits MUST be sent as zero and are ignored on + receipt. + + - Label.start and Label.end: If the BM bit is zero, this fine- + grained label [RFC7172] ID range is inclusive. These fields + are treated as unsigned integers. Setting them both to the + same label ID value indicates a range of one label ID. If + Label.end is less than Label.start, the sub-TLV is ignored. + + - Label.start and bit-map: If the BM bit is one, the fine-grained + labels that the IS is interested in are indicated by a 24-bit + bit-map. The interested labels are the Label.start number plus + the bit number of each one bit in the bit-map. So, if bit zero + of the bit-map is a one, the IS is interested in the label with + value Label.start, and if bit 23 of the bit-map is a one, the + IS is interested in the label with value Label.start+23. + + o Appointed Forwarder Status Lost Counter: This is a count of how + many times a port that was Appointed Forwarder for a VLAN mapping + to the fine-grained label in the range or bit-map given has lost + the status of being an Appointed Forwarder as discussed in Section + 4.8.3 of [RFC6325]. It is initialized to zero at an IS when the + zeroth LSP sequence number is initialized. No special action need + be taken at rollover; the counter just wraps around. + + + + +Eastlake, et al. Standards Track [Page 26] + +RFC 7176 TRILL Use of IS-IS May 2014 + + + o Root Bridges: The list of zero or more spanning tree root bridge + IDs is the set of root bridge IDs seen for all ports for which the + IS is Appointed Forwarder for a VLAN mapping to the fine-grained + label in the specified range or bit-map. (See [RFC6325], Section + 4.9.3.2.) While, of course, at most one spanning tree root could + be seen on any particular port, there may be multiple relevant + ports connected to different bridged LANs with different spanning + tree roots. + + An INT-LABEL sub-TLV asserts that the information provided (multicast + router attachment, Appointed Forwarder status lost counter, and root + bridges) is the same for all labels specified. If this is not the + case, the sub-TLV MUST be split into subranges and/or separate bit + maps meeting this criteria. It is always safe to use sub-TLVs with a + "range" of one VLAN ID, but this may be too verbose. + +2.3.9. RBridge Channel Protocols Sub-TLV + + An IS announces the RBridge Channel protocols [RFC7178] it supports + through use of this sub-TLV. + + +-+-+-+-+-+-+-+-+ + |Type=RBCHANNELS| (1 byte) + +-+-+-+-+-+-+-+-+ + | Length | (1 byte) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+... + | Zero or more bit vectors (variable) + +-+-+-+-... + + o Type: Router Capability and MT-Capability RBridge Channel + Protocols sub-TLV, set to 16 (RBCHANNELS). + + o Length: variable. + + o Bit Vectors: Zero or more byte-aligned bit vectors where a one bit + indicates support of a particular RBridge Channel protocol. Each + byte-aligned bit vector is formatted as follows: + + | 0 1 2 3 4 5 6 7| 8 9 10 11 12 13 14 15| + +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ + | Bit Vector Length | Bit Vector Offset | + +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ + | bits + +--+--+--... + + The Bit Vector Length (BVL) is a seven-bit unsigned integer field + giving the number of bytes of bit vector. The Bit Vector Offset + (BVO) is a nine-bit unsigned integer field. + + + +Eastlake, et al. Standards Track [Page 27] + +RFC 7176 TRILL Use of IS-IS May 2014 + + + The bits in each bit vector are numbered in network order, the + high-order bit of the first byte of bits being bit 0 + 8*BVO, the + low-order bit of that byte being 7 + 8*BVO, the high order bit of + the second byte being 8 + 8*BVO, and so on for BVL bytes. A bit + vector of RBridge Channel protocols supported MUST NOT extend + beyond the end of the value in the sub-TLV in which it occurs. If + it does, it is ignored. If multiple byte-aligned bit vectors are + present in one such sub-TLV, their representations are contiguous, + the BVL field for the next starting immediately after the last + byte of bits for the previous bit vector. The one or more bit + vectors present MUST exactly fill the sub-TLV value. If there are + one or two bytes of value left over, they are ignored; if more + than two, an attempt is made to parse them as one or more bit + vectors. + + If different bit vectors overlap in the protocol number space they + refer to and they have inconsistent bit values for a channel + protocol, support for the protocol is assumed if any of these bit + vectors has a 1 for that protocol. + + The absence of any occurrences of this sub-TLV in the LSP for an + IS implies that the IS does not support the RBridge Channel + facility. To avoid wasted space, trailing bit vector zero bytes + SHOULD be eliminated by reducing BVL, any null bit vectors (ones + with BVL equal to zero) eliminated, and generally the most compact + encoding used. For example, support for channel protocols 1 and + 32 could be encoded as + + BVL = 5 + BVO = 0 + 0b01000000 + 0b00000000 + 0b00000000 + 0b00000000 + 0b10000000 + + or as + + BVL = 1 + BVO = 0 + 0b01000000 + BLV = 1 + BVO = 4 + 0b1000000 + + The first takes 7 bytes while the second takes only 6; thus, the + second would be preferred. + + + + +Eastlake, et al. Standards Track [Page 28] + +RFC 7176 TRILL Use of IS-IS May 2014 + + + In multi-topology-aware RBridges, RBridge Channel protocols for which + support is announced in the base topology are assumed to be supported + in all topologies for which there is no separate announcement for + RBridge Channel protocol support. + +2.3.10. Affinity Sub-TLV + + Association of an IS to a multi-destination distribution tree through + a specific path is accomplished by using the Affinity sub-TLV. The + announcement of an Affinity sub-TLV by RB1 with the nickname of RB2 + as the first part of an Affinity Record in the sub-TLV value is a + request by RB1 that all ISs in the campus connect RB2 as a child of + RB1 when calculating any of the trees listed in that Affinity Record. + Examples of use include [Affinity] and [Resilient]. + + The structure of the Affinity sub-TLV is shown below. + + +-+-+-+-+-+-+-+-+ + | Type=AFFINITY | (1 byte) + +-+-+-+-+-+-+-+-+ + | Length | (1 byte) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | AFFINITY RECORD 1 | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | AFFINITY RECORD 2 | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | .......... + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | AFFINITY RECORD N | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + + where each AFFINITY RECORD is structured as follows: + + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Nickname | (2 bytes) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + |Affinity Flags | (1 byte) + +-+-+-+-+-+-+-+-+ + |Number of trees| (1 byte) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Tree-num of 1st root | (2 bytes) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Tree-num of 2nd root | (2 bytes) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | .......... | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Tree-num of Nth root | (2 bytes) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + + + +Eastlake, et al. Standards Track [Page 29] + +RFC 7176 TRILL Use of IS-IS May 2014 + + + o Type: Router Capability and MT-Capability sub-TLV type, set to 17 + (AFFINITY). + + o Length: size of all Affinity Records included, where an Affinity + Record listing n tree roots is 4+2*n bytes long. + + o Nickname: 16-bit nickname of the IS whose associations to the + multi-destination trees listed in the Affinity Record are through + the originating IS. + + o Affinity Flags: 8 bits reserved for future needs to provide + additional information about the affinity being announced. MUST + be sent as zero and ignored on receipt. + + o Number of trees: A one-byte unsigned integer giving the number of + trees for which affinity is being announced by this Affinity + Record. + + o Tree-num of roots: The tree numbers of the distribution trees this + Affinity Record is announcing. + + There is no need for a field giving the number of Affinity Records as + this can be determined by processing those records. + +2.3.11 Label Group Sub-TLV + + The Label Group sub-TLV consists of two or more fine-grained label + [RFC7172] IDs. This sub-TLV indicates that shared label MAC address + learning is occurring at the announcing IS between the listed labels. + It is structured as follows: + + +-+-+-+-+-+-+-+-+ + |Typ=LABEL-GROUP| (1 byte) + +-+-+-+-+-+-+-+-+ + | Length | (1 byte) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Primary Label ID | (3 bytes) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Secondary Label ID | (3 bytes) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | more Secondary Label IDs ... (3 bytes each) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + + o Type: Router Capability and MT-Capability sub-TLV type, set to 18 + (LABEL-GROUP). + + o Length: 6 + 3*n, where n is the number of secondary VLAN ID fields + beyond the first. n MAY be zero. + + + +Eastlake, et al. Standards Track [Page 30] + +RFC 7176 TRILL Use of IS-IS May 2014 + + + o Primary Label ID: This identifies the primary Label ID. + + o Secondary Label ID: This identifies a secondary Label ID in the + Label Group. + + o more Secondary Label IDs: zero or more byte triples, each with a + Label ID. + +2.4. MTU Sub-TLV for Extended Reachability and MT-ISN TLVs + + The MTU sub-TLV is used to optionally announce the MTU of a link as + specified in [RFC6325], Section 4.2.4.4. It occurs within the + Extended Reachability (#22) and MT-ISN (Intermediate System + Neighbors) (#222) TLVs. + + +-+-+-+-+-+-+-+-+ + | Type = MTU | (1 byte) + +-+-+-+-+-+-+-+-+ + | Length | (1 byte) + +-+-+-+-+-+-+-+-+ + |F| RESV | (1 byte) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | MTU | (2 bytes) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + + o Type: Extended Reachability and MT-ISN sub-TLV type, set to MTU + sub-TLV 28. + + o Length: 3. + + o F: Failed. This bit is a one if MTU testing failed on this link + at the required campus-wide MTU. + + o RESV: 7 bits that MUST be sent as zero and ignored on receipt. + + o MTU: This field is set to the largest successfully tested MTU size + for this link or zero if it has not been tested, as specified in + Section 4.3.2 of [RFC6325]. + +2.5. TRILL Neighbor TLV + + The TRILL Neighbor TLV is used in TRILL broadcast link IIH PDUs (see + Section 4.1 below) in place of the IS Neighbor TLV, as specified in + Section 4.4.2.1 of [RFC6325] and in [RFC7177]. The structure of the + TRILL Neighbor TLV is as follows: + + + + + + +Eastlake, et al. Standards Track [Page 31] + +RFC 7176 TRILL Use of IS-IS May 2014 + + + +-+-+-+-+-+-+-+-+ + | Type | (1 byte) + +-+-+-+-+-+-+-+-+ + | Length | (1 byte) + +-+-+-+-+-+-+-+-+ + |S|L|R| SIZE | (1 byte) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Neighbor RECORDS (1) | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Neighbor RECORDS (2) | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | ................. | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Neighbor RECORDS (N) | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + + The information present for each neighbor is as follows: + + +-+-+-+-+-+-+-+-+ + |F|O| RESV | (1 bytes) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | MTU | (2 bytes) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+...+-+-+-+-+-+ + | SNPA (MAC Address) | (SIZE bytes) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+...+-+-+-+-+-+ + + o Type: TLV type, set to TRILL Neighbor TLV 145. + + o Length: 1 + (SIZE+3)*n, where n is the number of neighbor records, + which may be zero. + + o S: Smallest flag. If this bit is a one, then the list of + neighbors includes the neighbor with the smallest MAC address + considered as an unsigned integer. + + o L: Largest flag. If this bit is a one, then the list of neighbors + includes the neighbor with the largest MAC address considered as + an unsigned integer. + + o R, RESV: These bits are reserved and MUST be sent as zero and + ignored on receipt. + + o SIZE: The SNPA size as an unsigned integer in bytes except that 6 + is encoded as zero. An actual size of zero is meaningless and + cannot be encoded. The meaning of the value 6 in this field is + reserved, and TRILL Neighbor TLVs received with a SIZE of 6 are + ignored. The SIZE is inherent to the technology of a link and is + fixed for all TRILL Neighbor TLVs on that link but may vary + + + +Eastlake, et al. Standards Track [Page 32] + +RFC 7176 TRILL Use of IS-IS May 2014 + + + between different links in the campus if those links are different + technologies, for example, 6 for EUI-48 SNPAs or 8 for EUI-64 + SNPAs [RFC7042]. (The SNPA size on the various links in a TRILL + campus is independent of the System ID size.) + + o F: Failed. This bit is a one if MTU testing to this neighbor + failed at the required campus-wide MTU (see [RFC6325], Section + 4.3.1). + + o O: OOMF. This bit is a one if the IS sending the enclosing TRILL + Neighbor TLV is willing to offer the Overload Originated Multi- + destination Frame (OOMF) service [RFC7180] to the IS whose port + has the SNPA in the enclosing Neighbor RECORD. + + o MTU: This field is set to the largest successfully tested MTU size + for this neighbor or to zero if it has not been tested. + + o SNPA (MAC Address): Subnetwork Point of Attachment of the + neighbor. + + As specified in [RFC7177] and Section 4.4.2.1 of [RFC6325], all MAC + addresses may fit into one TLV, in which case both the S and L flags + would be set to one in that TLV. If the MAC addresses don't fit into + one TLV, the highest MAC address in a TRILL Neighbor TLV with the L + flag zero MUST also appear as a MAC address in some other TRILL + Neighbor TLV (possibly in a different TRILL IIH PDU). Also, the + lowest MAC address in a TRILL Neighbor TLV with the S flag zero MUST + also appear in some other TRILL Neighbor TLV (possibly in a different + TRILL IIH PDU). If an IS believes it has no neighbors, it MUST send + a TRILL Neighbor TLV with an empty list of neighbor RECORDS, which + will have both the S and L bits on. + +3. MTU PDUs + + The IS-IS MTU-probe and MTU-ack PDUs are used to optionally determine + the MTU on a link between ISs as specified in Section 4.3.2 of + [RFC6325] and in [RFC7177]. + + The MTU PDUs have the IS-IS PDU common header (up through the Maximum + Area Addresses byte) with PDU Type numbers as indicated in Section 5. + They also have a common fixed MTU PDU header as shown below that is 8 + + 2*(ID Length) bytes long, 20 bytes in the case of the usual 6-bytes + System IDs. + + + + + + + + +Eastlake, et al. Standards Track [Page 33] + +RFC 7176 TRILL Use of IS-IS May 2014 + + + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | PDU Length | (2 bytes) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+.....+-+-+ + | Probe ID (6 bytes) | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+.....+-+-+ + | Probe Source ID (ID Length bytes) | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+.....+-+-+ + | Ack Source ID (ID Length bytes) | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+.....+-+-+ + + As with other IS-IS PDUs, the PDU Length gives the length of the + entire IS-IS packet starting with and including the IS-IS common + header. + + The Probe ID field is an opaque 48-bit quantity set by the IS issuing + an MTU-probe and copied by the responding IS into the corresponding + MTU-ack. For example, an IS creating an MTU-probe could compose this + quantity from a port identifier and probe sequence number relative to + that port. + + The Probe Source ID is set by an IS issuing an MTU-probe to its + System ID and copied by the responding IS into the corresponding MTU- + ack. The Ack Source ID is set to zero in MTU-probe PDUs and ignored + on receipt. An IS issuing an MTU-ack sets the Ack Source ID field to + its System ID. The System ID length is usually 6 bytes but could be + a different value as indicated by the ID Length field in the IS-IS + PDU Header. + + The TLV area follows the MTU PDU header area. This area MAY contain + an Authentication TLV and MUST be padded with the Padding TLV to the + exact size being tested. Since the minimum size of the Padding TLV + is 2 bytes, it would be impossible to pad to exact size if the total + length of the required information-bearing fixed fields and TLVs + added up to 1 byte less than the desired length. However, the length + of the fixed fields and substantive TLVs for MTU PDUs is expected to + be quite small compared with their minimum length (minimum 1470-byte + MTU on an IEEE 802.3 link, for example), so this should not be a + problem. + + + + + + + + + + + + + +Eastlake, et al. Standards Track [Page 34] + +RFC 7176 TRILL Use of IS-IS May 2014 + + +4. Use of Existing PDUs and TLVs + + The sub-sections below provide details of TRILL use of existing PDUs + and TLVs. + +4.1. TRILL IIH PDUs + + The TRILL IIH PDU is the variation of the IIH PDU used by the TRILL + protocol. Section 4.4 of the TRILL standard [RFC6325] and [RFC7177] + specify the contents of the TRILL IIH and how its use in TRILL + differs from Layer 3 LAN IIH PDU use. The adjacency state machinery + for TRILL neighbors is specified in detail in [RFC7177]. + + In a TRILL IIH PDU, the IS-IS common header and the fixed PDU Header + are the same as a Level 1 IIH PDU. + + The IS-IS Neighbor TLV (6) is not used in a TRILL IIH and is ignored + if it appears there. Instead, TRILL LAN IIH PDUs use the TRILL + Neighbor TLV (see Section 2.5). + +4.2. Area Address + + TRILL uses a fixed zero Area Address as specified in [RFC6325], + Section 4.2.3. This is encoded in a 4-byte Area Address TLV (TLV #1) + as follows: + + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | 0x01, Area Address Type | (1 byte) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | 0x02, Length of Value | (1 byte) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | 0x01, Length of Address | (1 byte) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | 0x00, zero Area Address | (1 byte) + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + +4.3. Protocols Supported + + NLPID (Network Layer Protocol ID) 0xC0 has been assigned to TRILL + [RFC6328]. A Protocols Supported TLV (#129, [RFC1195]) including + that value appears in TRILL IIH PDUs and LSP number zero PDUs. + +4.4. Link State PDUs (LSPs) + + An LSP number zero MUST NOT be originated larger than 1470 bytes, but + a larger LSP number zero successfully received MUST be processed and + forwarded normally. + + + + +Eastlake, et al. Standards Track [Page 35] + +RFC 7176 TRILL Use of IS-IS May 2014 + + +4.5. Originating LSP Buffer Size + + The originatingLSPBufferSize TLV (#14) MUST be in LSP number zero; + however, if found in other LSP fragments, it is processed normally. + Should there be more than one originatingLSPBufferSize TLV for an IS, + the minimum size, but not less than 1470, is used. + +5. IANA Considerations + + This section gives IANA considerations for the TLVs, sub-TLVs, and + PDUs specified herein. A number of new code points are assigned, and + those that were assigned by [RFC6326] are included here for + convenience. IANA has replaced all [RFC6326] references in the IANA + registries with references to this document. + +5.1. TLVs + + This document specifies two IS-IS TLV types -- namely, the Group + Address TLV (GADDR-TLV; type 142) and the TRILL Neighbor TLV (type + 145). The PDUs in which these TLVs are permitted for TRILL are shown + in the table below along with the section of this document where they + are discussed. The final "NUMBER" column indicates the permitted + number of occurrences of the TLV in their PDU, or set of PDUs in the + case of LSPs, which in these two cases is "*" indicating that the TLV + MAY occur 0, 1, or more times. + + IANA has registered these two code points in the IANA IS-IS TLV + registry (ignoring the "Section" and "NUMBER" columns, which are + irrelevant to that registry). + + Section TLV IIH LSP SNP Purge NUMBER + ======= === === === === ===== ====== + GADDR-TLV 2.1 142 n y n n * + TRILL Neighbor TLV 2.5 145 y n n n * + +5.2. Sub-TLVs + + This document specifies a number of sub-TLVs. The TLVs in which + these sub-TLVs occur are shown in the second table below along with + the section of this document where they are discussed. The TLVs + within which these sub-TLVs can occur are determined by the presence + of an "X" in the relevant column; the column headers are described in + the first table below. In some cases, the column header corresponds + to two different TLVs in which the sub-TLV can occur. + + + + + + + +Eastlake, et al. Standards Track [Page 36] + +RFC 7176 TRILL Use of IS-IS May 2014 + + + Column Head TLV RFC TLV Name + =========== ===== ======== ============== + Grp. Adr. 142 7176 Group Address + + MT Port 143 6165 MT-Port-Cap-TLV + + MT Cap. 242 4971 Router CAPABILITY + 144 6329 MT-Capability + + Ext. Reach 22 5305 Extended IS Reachability + 222 5120 MT-ISN + + The final "NUMBER" column below indicates the permitted number of + occurrences of the sub-TLV cumulatively within all occurrences of + their TLV(s) in those TLVs' carrying a PDU (or set of PDUs in the + case of LSPs), as follows: + + 0-1 = MAY occur zero or one times. + 1 = MUST occur exactly once. If absent, the PDU is ignored. If it + occurs more than once, results are unspecified. + * = MAY occur 0, 1, or more times. + + The values in the "Section" and "NUMBER" columns are irrelevant to + the IANA sub-registries. + + sub- Grp. MT MT Ext. + Name Section TLV# Adr. Port Cap. Reach NUMBER + ================================================================= + GMAC-ADDR 2.1.1 1 X - - - * + GIP-ADDR 2.1.2 2 X - - - * + GIPV6-ADDR 2.1.3 3 X - - - * + GLMAC-ADDR 2.1.4 4 X - - - * + GLIP-ADDR 2.1.5 5 X - - - * + GLIPV6-ADDR 2.1.6 6 X - - - * + VLAN-FLAGS 2.2.1 1 - X - - 1 + Enabled-VLANs 2.2.2 2 - X - - * + AppointedFwrdrs 2.2.3 3 - X - - * + PORT-TRILL-VER 2.2.4 7 - X - - 0-1 + VLANs-Appointed 2.2.5 8 - X - - * + NICKNAME 2.3.2 6 - - X - * + TREES 2.3.3 7 - - X - 0-1 + TREE-RT-IDs 2.3.4 8 - - X - * + TREE-USE-IDs 2.3.5 9 - - X - * + INT-VLAN 2.3.6 10 - - X - * + TRILL-VER 2.3.1 13 - - X - 0-1 + VLAN-GROUP 2.3.7 14 - - X - * + INT-LABEL 2.3.8 15 - - X - * + RBCHANNELS 2.3.9 16 - - X - * + + + +Eastlake, et al. Standards Track [Page 37] + +RFC 7176 TRILL Use of IS-IS May 2014 + + + AFFINITY 2.3.10 17 - - X - * + LABEL-GROUP 2.3.11 18 - - X - * + MTU 2.4 28 - - - X 0-1 + ================================================================= + Name Section sub- Grp. MT MT Ext. NUMBER + TLV# Adr. Port Cap. Reach + + IANA has entered the newly assigned sub-TLV numbers in the above + table in the relevant existing sub-TLV registries, as determined by + which column has an X for that sub-TLV. For the sub-TLVs from + NICKNAME through and including VLAN-GROUP, which previously existed + only in the registry of sub-TLVs under TLV 242, IANA has added each + sub-TLV with the same sub-TLV number to the existing registry for + sub-TLVs under TLV 144. + +5.3. PDUs + + The IS-IS PDUs registry remains as established in [RFC6326] except + that the references to [RFC6326] are updated to reference this + document. + +5.4. Reserved and Capability Bits + + Any reserved bits (R), bits in reserved fields (RESV), or + capabilities bits in the PORT-TRILL-VER and TRILL-VER sub-TLVs, which + are specified herein as "MUST be sent as zero and ignored on receipt" + or the like, are allocated based on IETF Review [RFC5226]. + + Two sub-registries have been created within the TRILL Parameters + Registry as follows: + + Sub-Registry Name: TRILL-VER Sub-TLV Capability Flags + Registration Procedures: IETF Review + Reference: (This document) + + Bit Description Reference + ===== ============= =========== + 0 Affinity sub-TLV support. [Affinity] + 1 FGL-safe [RFC7172] + 2-13 Unassigned + 14-31 Extended header flag support. [RFC7179] + + + + + + + + + + +Eastlake, et al. Standards Track [Page 38] + +RFC 7176 TRILL Use of IS-IS May 2014 + + + Sub-Registry Name: PORT-TRILL-VER Sub-TLV Capability Flags + Registration Procedures: IETF Review + Reference: (This document) + + Bit Description Reference + ===== ============= =========== + 0 Hello reduction support. [RFC7180] + 1-2 Unassigned + 3-13 Hop-by-hop extended flag support. [RFC7179] + 14-31 Unassigned + +5.5. TRILL Neighbor Record Flags + + A sub-registry has been created within the TRILL Parameters Registry + as follows: + + Sub-Registry Name: TRILL Neighbor TLV NEIGHBOR RECORD Flags + Registration Procedures: Standards Action + Reference: (This document) + + Bit Short Name Description Reference + ============== ============= =========================== + 0 Fail Failed MTU test [RFC6325][RFC7176][RFC7177] + 1 OOMF Offering OOMF service [RFC7180] + 2-7 - Unassigned + +6. Security Considerations + + For general TRILL protocol security considerations, see the TRILL + base protocol standard [RFC6325]. + + This document raises no new security issues for IS-IS. IS-IS + security may be used to secure the IS-IS messages discussed here. + See [RFC5304] and [RFC5310]. Even when IS-IS authentication is used, + replays of Hello packets can create denial-of-service conditions; see + [RFC6039] for details. These issues are similar in scope to those + discussed in Section 6.2 of [RFC6325], and the same mitigations may + apply. + +7. Changes from RFC 6326 + + Non-editorial changes from [RFC6326] are summarized in the list + below: + + 1. Added five sub-TLVs under the Group Address (GADDR) TLV covering + VLAN-labeled IPv4 and IPv6 addresses and fine-grained-labeled + MAC, IPv4, and IPv6 addresses (Sections 2.1.2, 2.1.3, 2.1.4, + 2.1.5, and 2.1.6). + + + +Eastlake, et al. Standards Track [Page 39] + +RFC 7176 TRILL Use of IS-IS May 2014 + + + 2. Added the PORT-TRILL-VER sub-TLV (Section 2.2.4). + + 3. Added the VLANs-Appointed sub-TLV (Section 2.2.5). + + 4. Changed the TRILL-VER sub-TLV as listed below. + + a. Added 4 bytes of TRILL Header extended flags and capabilities + supported information. + + b. Required that the TRILL-VER sub-TLV appear in LSP number + zero. + + The above changes to TRILL-VER are backward compatible because + the [RFC6326]-conformant implementations of TRILL thus far have + only supported version zero and not supported any optional + capabilities or extended flags, the level of support indicated by + the absence of the TRILL-VER sub-TLV. Thus, if an + [RFC6326]-conformant implementation of TRILL rejects this sub-TLV + due to the changes specified in this document, it will, at worst, + decide that support of version zero and no extended flags or + capabilities is indicated, which is the best an + [RFC6326]-conformant implementation of TRILL can do anyway. + Similarly, a TRILL implementation that supports TRILL-VER as + specified herein and rejects TRILL-VER sub-TLVs in an + [RFC6326]-conformant TRILL implementation because they are not in + LSP number zero will decide that the implementation supports only + version zero with no extended flag or capabilities support, which + will be correct (Section 2.3.1). + + 5. Clarified the use of invalid VLAN IDs (0x000 and 0xFFF) in the + Appointed Forwarders sub-TLV and the Interested VLANs and + Spanning Tree Roots sub-TLV (Sections 2.2.3 and 2.3.6). + + 6. Added the Interested Labels and Spanning Tree Roots sub-TLV to + indicate attachment of an IS to a fine-grained label [RFC7172] + analogous to the existing Interested VLANs and Spanning Tree + Roots sub-TLV for VLANs (Section 2.3.8). + + 7. Added the RBridge Channel Protocols sub-TLV so ISs can announce + the RBridge Channel protocols they support (Section 2.3.9). + + 8. Permitted specification of the length of the link SNPA field in + TRILL Neighbor TLVs. This change is backward compatible because + the size of 6 bytes is specially encoded as zero, the previous + value of the bits in the new SIZE field (Section 2.5). + + + + + + +Eastlake, et al. Standards Track [Page 40] + +RFC 7176 TRILL Use of IS-IS May 2014 + + + 9. Made the size of the MTU PDU Header Probe Source ID and Ack + Source ID fields be the ID Length from the IS-IS PDU Header + rather than the fixed value 6 (Section 3). + + 10. For robustness, required that LSP number zero PDUs be originated + as no larger than 1470 bytes but processed regardless of size + (Section 4.4). + + 11. Required that the originatingLSPBufferSize TLV, if present, + appear in LSP number zero (Section 4.5). + + 12. Created sub-registries for and specified the IANA Considerations + policy for reserved and capability bits in the TRILL version sub- + TLVs (Section 5.4). + + 13. Added the distribution tree Affinity sub-TLV so ISs can request + distribution tree attachments (Section 2.3.10). + + 14. Added the LABEL-GROUP sub-TLV analogous to the VLAN-GROUP sub-TLV + (Section 2.3.11). + + 15. Added multi-topology to permit sub-TLVs previously only in the + Router Capability TLV to also appear in the MT-Capability TLV and + to permit the MTU sub-TLV previously limited to the Extended + Reachability TLV to also appear in the MT-ISN TLV. + + 16. Added a sub-registry for Neighbor TLV Neighbor RECORD flag bits + (Section 5.5). + + 17. Explicitly stated that if the number of sources in a GADDR-TLV + sub-TLV is zero, it indicates a listener for (*,G), that is, a + listener not restricted by source (Section 2.1). + +8. References + +8.1. Normative References + + [ISO-10589] + International Organization for Standardization, + "Intermediate System to Intermediate System intra-domain + routeing information exchange protocol for use in + conjunction with the protocol for providing the + connectionless-mode network service (ISO 8473)", Second + Edition, November 2002. + + [RFC1195] Callon, R., "Use of OSI IS-IS for routing in TCP/IP and + dual environments", RFC 1195, December 1990. + + + + +Eastlake, et al. Standards Track [Page 41] + +RFC 7176 TRILL Use of IS-IS May 2014 + + + [RFC1982] Elz, R. and R. Bush, "Serial Number Arithmetic", RFC 1982, + August 1996. + + [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate + Requirement Levels", BCP 14, RFC 2119, March 1997. + + [RFC4971] Vasseur, JP., Ed., Shen, N., Ed., and R. Aggarwal, Ed., + "Intermediate System to Intermediate System (IS-IS) + Extensions for Advertising Router Information", RFC 4971, + July 2007. + + [RFC5120] Przygienda, T., Shen, N., and N. Sheth, "M-ISIS: Multi + Topology (MT) Routing in Intermediate System to + Intermediate Systems (IS-ISs)", RFC 5120, February 2008. + + [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an + IANA Considerations Section in RFCs", BCP 26, RFC 5226, + May 2008. + + [RFC5305] Li, T. and H. Smit, "IS-IS Extensions for Traffic + Engineering", RFC 5305, October 2008. + + [RFC6165] Banerjee, A. and D. Ward, "Extensions to IS-IS for Layer-2 + Systems", RFC 6165, April 2011. + + [RFC6325] Perlman, R., Eastlake 3rd, D., Dutt, D., Gai, S., and A. + Ghanwani, "Routing Bridges (RBridges): Base Protocol + Specification", RFC 6325, July 2011. + + [RFC6328] Eastlake 3rd, D., "IANA Considerations for Network Layer + Protocol Identifiers", BCP 164, RFC 6328, July 2011. + + [RFC6329] Fedyk, D., Ed., Ashwood-Smith, P., Ed., Allan, D., Bragg, + A., and P. Unbehagen, "IS-IS Extensions Supporting IEEE + 802.1aq Shortest Path Bridging", RFC 6329, April 2012. + + [RFC6439] Perlman, R., Eastlake, D., Li, Y., Banerjee, A., and F. + Hu, "Routing Bridges (RBridges): Appointed Forwarders", + RFC 6439, November 2011. + + [RFC7172] Eastlake 3rd, D., Zhang, M., Agarwal, P., Perlman, R., and + D. Dutt, "Transparent Interconnection of Lots of Links + (TRILL): Fine-Grained Labeling", RFC 7172, May 2014. + + [RFC7177] Eastlake 3rd, D., Perlman, R., Ghanwani, A., Yang, Y., and + V. Manral, "Transparent Interconnection of Lots of Links + (TRILL): Adjacency", RFC 7177, May 2014. + + + + +Eastlake, et al. Standards Track [Page 42] + +RFC 7176 TRILL Use of IS-IS May 2014 + + + [RFC7178] Eastlake 3rd, D., Manral, V., Li, Y., Aldrin, S., and D. + Ward, "Transparent Interconnection of Lots of Links + (TRILL): RBridge Channel Support", RFC 7178, May 2014. + + [RFC7179] Eastlake 3rd, D., Ghanwani, A., Manral, V., Li, Y., and C. + Bestler, "Transparent Interconnection of Lots of Links + (TRILL): Header Extension", RFC 7179, May 2014. + + [RFC7180] Eastlake 3rd, D., Zhang, M., Ghanwani, A., Manral, V., and + A. Banerjee, "Transparent Interconnection of Lots of + Links (TRILL): Clarifications, Corrections, and Updates", + RFC 7180, May 2014. + +8.2. Informative References + + [Err2869] RFC Errata, Errata ID 2869, RFC 6326, + <http://www.rfc-editor.org>. + + [RFC5304] Li, T. and R. Atkinson, "IS-IS Cryptographic + Authentication", RFC 5304, October 2008. + + [RFC5310] Bhatia, M., Manral, V., Li, T., Atkinson, R., White, R., + and M. Fanto, "IS-IS Generic Cryptographic + Authentication", RFC 5310, February 2009. + + [RFC6039] Manral, V., Bhatia, M., Jaeggli, J., and R. White, "Issues + with Existing Cryptographic Protection Methods for Routing + Protocols", RFC 6039, October 2010. + + [RFC6326] Eastlake, D., Banerjee, A., Dutt, D., Perlman, R., and A. + Ghanwani, "Transparent Interconnection of Lots of Links + (TRILL) Use of IS-IS", RFC 6326, July 2011. + + [RFC7042] Eastlake 3rd, D. and J. Abley, "IANA Considerations and + IETF Protocol and Documentation Usage for IEEE 802 + Parameters", BCP 141, RFC 7042, October 2013. + + [RFC7175] Manral, V., Eastlake 3rd, D., Ward, D., and A. Banerjee, + "Transparent Interconnection of Lots of Links (TRILL): + Bidirectional Forwarding Detection (BFD) Support", RFC + 7175, May 2014. + + [Affinity] Senevirathne, T., Pathangi, J., and J. Hudson, + "Coordinated Multicast Trees (CMT) for TRILL", Work in + Progress, April 2014. + + + + + + +Eastlake, et al. Standards Track [Page 43] + +RFC 7176 TRILL Use of IS-IS May 2014 + + + [MultiLevel] + Perlman, R., Eastlake 3rd, D., Ghanwani, A., and H. Zhai, + "Flexible Multilevel TRILL (Transparent Interconnection of + Lots of Links)", Work in Progress, January 2014. + + [Resilient] + Zhang, M. Senevirathne, T., Pathangi, J., Banerjee, A., + and A. Ghanwani, "TRILL Resilient Distribution Trees", + Work in Progress, December 2013. + +9. Acknowledgements + + The authors gratefully acknowledge the contributions and reviews by + the following individuals: Ross Callon, Spencer Dawkins, Adrian + Farrel, Alexey Melnikov, Radia Perlman, Carlos Pignataro, and Joe + Touch. + + The authors also acknowledge the contributions to [RFC6326] by the + following individuals: Mike Shand, Stewart Bryant, Dino Farinacci, + Les Ginsberg, Sam Hartman, Dan Romascanu, Dave Ward, and Russ White. + In particular, thanks to Mike Shand for his detailed and helpful + comments. + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +Eastlake, et al. Standards Track [Page 44] + +RFC 7176 TRILL Use of IS-IS May 2014 + + +Authors' Addresses + + Donald Eastlake 3rd + Huawei Technologies + 155 Beaver Street + Milford, MA 01757 + USA + + Phone: +1-508-333-2270 + EMail: d3e3e3@gmail.com + + + Tissa Senevirathne + Cisco Systems + 375 East Tasman Drive, + San Jose, CA 95134 + USA + + Phone: +1-408-853-2291 + EMail: tsenevir@cisco.com + + + Anoop Ghanwani + Dell + 5450 Great America Parkway + Santa Clara, CA 95054 + USA + + EMail: anoop@alumni.duke.edu + + + Dinesh Dutt + Cumulus Networks + 1089 West Evelyn Avenue + Sunnyvale, CA 94086 + USA + + EMail: ddutt.ietf@hobbesdutt.com + + + Ayan Banerjee + Insieme Networks + 210 West Tasman Drive + San Jose, CA 95134 + USA + + EMail: ayabaner@gmail.com + + + + +Eastlake, et al. Standards Track [Page 45] + |