Network Working Group A. Banerjee, Ed.
Internet-Draft Cisco Systems
Intended status: Standards Track March 8, 2010
Expires: September 9, 2010
Extensions to IS-IS for Layer-2 Systems
draft-ietf-isis-layer2-03
Abstract
This document specifies the IS-IS extensions necessary to support
multi-link IPv4 and IPv6 networks, as well as to provide true link
state routing to any protocols running directly over layer 2. While
supporting this concept involves several pieces, this document only
describes extensions to IS-IS. We leave it to the systems using
these IS-IS extensions to explain how the information carried in
IS-IS is used.
Status of this Memo
This Internet-Draft is submitted to IETF in full conformance with the
provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on September 9, 2010.
Copyright Notice
Copyright (c) 2010 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
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Table of Contents
1. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4
2. PDU, TLV and sub-TLV Enhancements to IS-IS . . . . . . . . . . 4
2.1. The MAC-Reachability TLV . . . . . . . . . . . . . . . . . 4
2.2. The Group Address TLV . . . . . . . . . . . . . . . . . . 6
2.2.1. The Group MAC Address sub-TLV . . . . . . . . . . . . 6
2.2.2. The Group IP Address sub-TLV . . . . . . . . . . . . . 8
2.2.3. The Group IPv6 Address sub-TLV . . . . . . . . . . . . 10
2.2.4. The SPBV MAC Address sub-TLV . . . . . . . . . . . . . 11
2.3. Multi Topology aware Port Capability TLV . . . . . . . . . 13
2.3.1. The Special VLANs and Flags sub-TLV . . . . . . . . . 14
2.3.2. Enabled VLANs sub-TLV . . . . . . . . . . . . . . . . 15
2.3.3. Appointed Forwarders sub-TLV . . . . . . . . . . . . . 16
2.3.4. Hop-by-Hop Options (HBHOPT) sub-TLV . . . . . . . . . 17
2.3.5. Base VLAN-Identifiers sub-TLV . . . . . . . . . . . . 18
2.3.6. SPB Digest sub-TLV . . . . . . . . . . . . . . . . . . 19
2.3.7. Site Identifier sub-TLV . . . . . . . . . . . . . . . 21
2.3.8. Site Group IPv4 sub-TLV . . . . . . . . . . . . . . . 21
2.3.9. Site Group IPv6 sub-TLV . . . . . . . . . . . . . . . 22
2.3.10. Adjacency Server IPv4 sub-TLV . . . . . . . . . . . . 22
2.3.11. Adjacency Server IPv6 sub-TLV . . . . . . . . . . . . 23
2.4. Sub-TLVs for the Router Capability TLV . . . . . . . . . . 23
2.4.1. The TRILL Version sub-TLV . . . . . . . . . . . . . . 23
2.4.2. The Nickname sub-TLV . . . . . . . . . . . . . . . . . 24
2.4.3. The Trees sub-TLV . . . . . . . . . . . . . . . . . . 25
2.4.4. The Tree Identifiers Sub-TLV . . . . . . . . . . . . . 26
2.4.5. The Trees Used Identifiers Sub-TLV . . . . . . . . . . 27
2.4.6. Interested VLANs and Spanning Tree Roots sub-TLV . . . 27
2.4.7. The VLAN Group sub-TLV . . . . . . . . . . . . . . . . 29
2.4.8. The Ingress-to-Egress Options (ITEOPT) sub-TLV . . . . 30
2.4.9. VLAN Mapping (VMAP) sub-TLV . . . . . . . . . . . . . 31
2.5. Multi Topology Aware Capability TLV . . . . . . . . . . . 32
2.5.1. SPB Instance sub-TLV . . . . . . . . . . . . . . . . . 33
2.5.2. SPBM Service Identifier and Unicast Address sub-TLV . 36
2.6. Sub-TLVs of the Extended Reachability TLV . . . . . . . . 37
2.6.1. SPB Link Metric sub-TLV . . . . . . . . . . . . . . . 37
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2.6.2. MTU sub-TLV . . . . . . . . . . . . . . . . . . . . . 38
2.7. TRILL Neighbor TLV . . . . . . . . . . . . . . . . . . . . 39
2.8. The Group Membership Active Source TLV . . . . . . . . . . 40
2.8.1. The Group MAC Active Source sub-TLV . . . . . . . . . 41
2.8.2. The Group IP Active Source sub-TLV . . . . . . . . . . 42
2.8.3. The Group IPv6 Active Source sub-TLV . . . . . . . . . 44
2.9. PDU Extensions to IS-IS . . . . . . . . . . . . . . . . . 46
2.9.1. The Multicast Group PDU . . . . . . . . . . . . . . . 46
2.9.2. The TRILL-Hello PDU . . . . . . . . . . . . . . . . . 48
2.9.3. The MTU PDU . . . . . . . . . . . . . . . . . . . . . 49
3. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 50
4. Security Considerations . . . . . . . . . . . . . . . . . . . 50
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 50
6. Contributing Authors . . . . . . . . . . . . . . . . . . . . . 53
7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 54
7.1. Normative References . . . . . . . . . . . . . . . . . . . 54
7.2. Informative References . . . . . . . . . . . . . . . . . . 55
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 55
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1. Overview
There are a number of systems (for example, [RBRIDGES], [802.1aq])
that use layer 2 addresses carried in a link state routing protocol,
specifically IS-IS [IS-IS] [RFC1195], to provide true layer 2
routing. This document specifies a set of TLVs and sub-TLVs to be
added to [IS-IS] level 1 PDUs, and six new PDU types, to support
these proposed systems. Some of these TLVs are generic layer 2
additions and some are specific to [RBRIDGES] or to [802.1aq]. This
draft does not propose any new forwarding mechanisms using this
additional information carried within IS-IS.
This document specifies additional TLVs and sub-TLVs, to carry
unicast and multicast attached address information. It also
specifies additional TLVs and sub-TLVs to carry information as
required by the IETF TRILL and IEEE 802.1aq protocols.
This document specifies six new IS-IS PDUs. The Multicast Group
(MGROUP) PDU, for carrying a list of attached or joined multicast
groups. The Multicast Group Complete Sequence Number (MGROUP-CSNP)
PDU and the Multicast Group Partial Sequence Number (MGROUP-PSNP) PDU
packets are also defined to be used with the new MGROUP-PDU to
perform database exchange on the MGROUP PDUs. The TRILL-Hello PDU
provides the subnet specific layer of IS-IS for TRILL links. The
MTU-probe and MTU-ack PDUs provide a means of testing link MTU.
1.1. Terminology
The term "Hello" or "Hello PDU" in this document, when not further
qualified, includes the TRILL IIH PDU, the LAN IIH PDU and the P2P
IIH PDU.
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 RFC 2119.
2. PDU, TLV and sub-TLV Enhancements to IS-IS
In this section we specify the enhancements for the PDUs, TLVs and
sub-TLVs as needed by Layer-2 technologies.
2.1. The MAC-Reachability TLV
The MAC-Reachability (MAC-RI) TLV is IS-IS TLV type 141 and has the
following format:
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+-+-+-+-+-+-+-+-+
| Type= MAC-RI | (1 byte)
+-+-+-+-+-+-+-+-+
| Length | (1 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Topology-Id/ Nickname | (2 bytes)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Confidence | (1 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| RESV | VLAN-ID | (2 bytes)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MAC (1) (6 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ................. |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MAC (N) (6 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
o Type: TLV Type, set to 141 (MAC-RI).
o Length: Total number of bytes contained in the value field given
by 5 + 6*n bytes.
o Confidence: This carries an 8-bit quantity indicating the
confidence level in the MAC addresses being transported. Whether
this field is used, and its semantics if used, are further defined
by the specific protocol using Layer-2-IS-IS. If not used, it
MUST be set to zero on transmission and be ignored on receipt.
o Topology-Id/Nickname : Depending on the technology in which it is
used, this carries the topology-id or nickname. When this field
is set to zero this implies that the MAC addresses are reachable
across all topologies or across all nicknames of the originating
IS.
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 MAC addresses in this TLV, or the value zero if no
VLAN is specified.
o MAC(i): This is the 48-bit MAC address reachable from the IS that
is announcing this TLV.
The MAC-RI TLV is carried in a standard Level 1 link state PDU. It
MUST contain only unicast addresses.
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2.2. The Group Address TLV
The Group Address (GADDR) TLV is IS-IS TLV type 142 [TBD] and has the
following format:
+-+-+-+-+-+-+-+-+
| Type=GADDRTLV | (1 byte)
+-+-+-+-+-+-+-+-+
| Length | (1 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| sub-TLVs (variable bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
o Type: TLV Type, set to GADDR-TLV 142 [TBD].
o Length: Total number of bytes contained in the value field, which
includes the length of the sub-TLVs carried in this TLV.
o sub-TLVs: The Group Address TLV value contains sub-TLVs formatted
as described in [RFC5305]. The sub-TLVs for this TLV are
specified in the following subsections.
The GADDR TLV is carried only within a Multicast Group Level 1 link
state PDU.
2.2.1. The Group MAC Address sub-TLV
The Group MAC Address (GMAC-ADDR) sub-TLV is IS-IS sub-TLV type 1
within the GADDR TLV and has the following format:
+-+-+-+-+-+-+-+-+
| Type=GMAC-ADDR| (1 byte)
+-+-+-+-+-+-+-+-+
| Length | (1 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Topology-Id/ Nickname | (2 bytes)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Confidence | (1 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| RESV | VLAN-ID | (2 bytes)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Num Group Recs | (1 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| GROUP RECORDS (1) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ................. |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| GROUP RECORDS (N) |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
where each group record is of the form:
+-+-+-+-+-+-+-+-+
| RESERVED | (1 byte)
+-+-+-+-+-+-+-+-+
| Num of Sources| (1 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Group Address (6 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Source 1 Address (6 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Source 2 Address (6 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Source M Address (6 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
o Type: sub-TLV Type, set to 1 (GMAC-ADDR) of length 1 byte.
o Length: Total number of bytes contained in the value field.
o Confidence: This carries an 8-bit quantity indicating the
confidence level in the MAC addresses being transported. Whether
this field is used, and its semantics if used, are further defined
by the specific protocol using Layer-2-IS-IS. If not used, it
MUST be set to zero on transmission and be ignored on receipt.
o Topology-Id/Nickname : Depending on the technology in which it is
used, this carries the topology-id or nickname. When this field
is set to zero this implies that the MAC addresses are reachable
across all topologies or across all nicknames of the originating
IS.
o RESERVED: 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 MAC addresses in this TLV, or the value zero if no
VLAN is specified.
o Number of Group Records: This is of length 1 byte and lists the
number of group records in this TLV.
o Group Record: Each group record has a one byte reserved space and
the next byte carries the number of sources. It then has a 48-bit
multicast Group Address followed by 48-bit source MAC addresses.
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An address being a group multicast address or unicast source
address can be checked using the multicast bit in the address. 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 GMAC-ADDR sub-TLV is carried only within a GADDR TLV and MUST be
carried in a standard Level 1 link state MGROUP PDU.
2.2.2. The Group IP Address sub-TLV
The Group IP Address (GIP-ADDR) sub-TLV IS-IS sub-TLV type 2 within
the GADDR TLV and has the following format:
+-+-+-+-+-+-+-+-+
| Type=GIP-ADDR |
+-+-+-+-+-+-+-+-+
| Length | (1 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Topology-Id/ Nickname | (2 bytes)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Confidence | (1 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| RESV | VLAN-ID | (2 bytes)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Num Group Recs | (1 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| GROUP RECORDS (1) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ................. |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| GROUP RECORDS (N) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
where each group record is of the form:
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+-+-+-+-+-+-+-+-+
| RESERVED | (1 byte)
+-+-+-+-+-+-+-+-+
| Num of Sources| (1 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Group Address (4 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Source 1 Address (4 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Source 2 Address (4 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Source M Address (4 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
o Type: sub-TLV Type, set to 2 (GIP-ADDR).
o Length: Total number of bytes contained in the value field of the
TLV.
o Confidence: This carries an 8-bit quantity indicating the
confidence level in the IP addresses being transported. Whether
this field is used, and its semantics if used, are further defined
by the specific protocol using Layer-2-IS-IS. If not used, it
must be set to zero on transmission and be ignored on receipt.
o Topology-Id/Nickname : Depending on the technology in which it is
used, this carries the topology-id or nickname. When this field
is set to zero this implies that the addresses are reachable
across all topologies or across all nicknames of the originating
IS.
o RESERVED: 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 TLV, or the value zero if no VLAN
is specified.
o Number of Group Records: This is of length 1 byte and lists the
number of group records in this TLV.
o Group Record: Each group record has a one byte reserved space and
the next byte carries the number of sources. It is followed by a
32-bit IPv4 Group Address followed by 32-bit 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 repeated in another sub-TLV of another
instance of the Group Address TLV.
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The GIP-ADDR sub-TLV is carried only within a GADDR TLV and MUST be
carried in a standard Level 1 link state MGROUP PDU.
2.2.3. The Group IPv6 Address sub-TLV
The Group IPv6 Address (GIPV6-ADDR) TLV is IS-IS sub-TLV type 3 and
has the following format:
+-+-+-+-+-+-+-+-+
|Type=GIPv6-ADDR|
+-+-+-+-+-+-+-+-+
| Length | (1 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Topology-Id/ Nickname | (2 bytes)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Confidence | (1 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| RESV | VLAN-ID | (2 bytes)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Num Group Recs | (1 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| GROUP RECORDS (1) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ................. |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| GROUP RECORDS (N) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
where each group record is of the form:
+-+-+-+-+-+-+-+-+
| RESERVED | (1 byte)
+-+-+-+-+-+-+-+-+
| Num of Sources| (1 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Group Address (16 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Source 1 Address (16 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Source 2 Address (16 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Source M Address (16 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
o Type: sub-TLV Type, set to 3 (GIPV6-ADDR).
o Length: Total number of bytes contained in the value field.
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o Confidence: This carries an 8-bit quantity indicating the
confidence level in the IPv6 addresses being transported. Whether
this field is used, and its semantics if used, are further defined
by the specific protocol using Layer-2-IS-IS. If not used, it
must be set to zero on transmission and be ignored on receipt.
o Topology-Id/Nickname : Depending on the technology in which it is
used, this carries the topology-id or nickname. When this field
is set to zero this implies that the addresses are reachable
across all topologies or across all nicknames of the originating
IS.
o RESERVED: 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 TLV, or the value zero if no VLAN
is specified.
o Number of Group Records: This of length 1 byte and lists the
number of group records in this TLV.
o Group Record: Each group record has a one byte reserved space and
the next byte carries the number of sources. It is followed by a
128-bit multicast IPv6 Group Address followed by 128-bit 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 repeated in another sub-TLV in
another instance of the Group Address TLV.
The GIPV6-ADDR sub-TLV is carried only within a GADDR TLV and MUST be
carried in a standard Level 1 link state MGROUP PDU.
2.2.4. The SPBV MAC Address sub-TLV
The SPBV MAC Address (SPBV-MAC-ADDR) TLV is IS-IS sub-TLV type 4 and
has the following format:
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+-+-+-+-+-+-+-+-+
| Type=SPBV-ADDR| (1 byte)
+-+-+-+-+-+-+-+-+
| Length | (1 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|R|R|S|R| SPVID | (2 bytes)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|T|R| Reserved | MAC 1 Address | (1+6 bytes)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|T|R| Reserved | MAC N Address | (1+6 bytes)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
o Type: sub-TLV Type, set to 4 (SPBV-MAC-ADDR).
o Length: Total number of bytes contained in the value field. The
number of MAC address associated with the SPVID is computed by
(Length - 2)/7.
o SR bits (2-bits) The SR bits are the service requirement parameter
from MMRP. The service requirement parameters have the value 0
(Forward all Groups) and 1 (Forward All Unregistered Groups)
defined. However this attribute may also be missing. So the SR
bits are defined as 0 not declared, 1 Forward all Groups and 2
Forward All Unregistered Groups. These bits have a two Reserved
bits set before them.
o SPVID (12-bits) The SPVID and by association Base VID and the ECT-
ALGORITHM and SPT Set that the MAC addresses defined below will
use. If the SPVID is not allocated the SPVID Value is 0. Note
that if the ECT-Algorithm in use is Spanning Tree Algorithm this
value should be populated with the Base VID and the MAC can be
populated.
o T Bit (1-bit) This is the Transmit allowed Bit for the following
group MAC address. This is an indication that SPBV Group MAC
Address with SPVID of source should be populated (for the bridge
advertising this Group MAC), and installed in the FDB of transit
bridges, when the bridge computing the trees is on the
corresponding ECT-ALGORITHM shortest path between the bridge
advertising this MAC with the T bit set, and any receiver of this
Group MAC Address. A bridge that does not advertise this bit set
for an Group MAC Address should have no forwarding state installed
for traffic originating from that bridge on other transit bridges
in the network.
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o R Bit (1-bit) This is the Receive allowed Bit for the following
Group MAC Address. This is an indication that SPBV Group MAC
Addresses as receiver should be populated (for bridges advertising
this Group MAC Address with the T bit set) and installed when the
bridge computing the trees lies on the corresponding shortest path
for this ECT-ALGORITHM between this receiver and any transmitter
on this Group MAC Address. An entry that does not have this bit
set for a Group MAC Address is prevented from receiving on this
Group MAC Address because transit bridges will not install
multicast forwarding state towards it in their FDBs or the traffic
is explicitly filtered.
o MAC Address (48-bits) The MAC is the address is either a group
address or an individual address. Individual addresses are
optional and normal MAC learning can be used. When the MAC
address is a group address it declares this bridge as part of the
multicast interest for this destination MAC address. Multicast
trees can be efficiently constructed for destination by populating
multicast FDB entries for the subset of the shortest path tree
that connects the bridges supporting the multicast address. This
replaces the function of MMRP for SPTs. The T and R bits above
have meaning if this is a group address. Individual addresses are
populated only as if the R bit was not set.
The SPBV-MAC-ADDR sub-TLV is carried within the GADDR TLV and MUST be
carried only in a standard Level 1 link state MGROUP PDU.
2.3. Multi Topology aware Port Capability TLV
The Multi Topology aware Port Capability (MT-PORT-CAP) is an IS-IS
TLV type 143 [TBD], and has the following format:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Type=MT PORTCAP| Length |O|R|R|R| Topology Identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| sub-TLVs |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
o Type: TLV Type, set to MT-PORT-CAP TLV 143 [TBD].
o Length: Total number of bytes contained in the value field,
including the length of the sub-TLVs carried in this TLV.
o O bit: The overload bit that follows the semantics associated with
an overloaded intermediate system.
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o Topology Identifier: MT ID is a 12-bit field containing the MT ID
of the topology being announced. This field when set to zero
implies that it is being used to carry base topology information.
In TRILL this value is set to ZERO, however, in IEEE SPB and SPBB,
it may be non-zero.
o sub-TLVs: The MT aware Port Capabilities TLV value contains sub-
TLVs formatted as described in [RFC5305]. They are defined in the
next sections.
The MT-PORT-CAP TLV may occur multiple times, and is carried only
within a Hello PDU.
2.3.1. The Special VLANs and Flags sub-TLV
The Special VLANs and Flags (VLAN and Flags) sub-TLV MUST only appear
in a MT-PORT-CAP TLV. This is carried exactly once in every TRILL
IIH PDU. It has the following format:
+-+-+-+-+-+-+-+-+
|Type=VLAN Flags| (1 byte)
+-+-+-+-+-+-+-+-+
| Length | (1 byte)
+--------------------------------+
| Port ID | (2 bytes)
+--------------------------------+
| Sender Nickname | (2 bytes)
+--+--+--+--+--------------------+
|AF|AC|VM|BY| Outer.VLAN | (2 bytes)
+-----------+--------------------+
|Reserved | Desig.VLAN | (2 bytes)
+-----------+--------------------+
o Type: TLV Type, set to VLAN and Flags sub-TLV 1 [TBD].
o Length: 8 - Number of bytes contained in the value field.
o Port ID: An ID for the port on which the enclosing TRILL IIH PDU
is being sent. The transmitting RBridge assigns this ID such that
each of its ports has an ID different from all of its other ports.
o Sender nickname: If the sending intermediate system is holding any
nicknames, one MUST be included here. Otherwise, the field is set
to zero. This field is to support intelligent end stations that
determine the egress RBridge for unicast data through a directory
service or the like and need a nickname for their first hop to
insert as the ingress nickname to correctly format a TRILL
encapsulated data frame.
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o The fifth and sixth bytes have a copy of the Outer VLAN ID
associated with the Hello frame when it was sent. The lower 4
bits of the fifth byte give the upper ID bits of the VLAN ID and
the sixth byte gives the lower VLAN ID bits.
o The upper 4 bits of the fifth byte are flag bits as shown. The AF
bit, if one, indicates that the sending Intermediate System
believes it is Appointed Forwarder for the VLAN and port on which
the Hello was sent. The AC bit, if one, indicates that the
sending port is configured as an access port. The VM bit, if a
one, indicates that the sending Intermediate System has detected
VLAN mapping within the link. The BY bit, if set, indicates
bypass psuedonode.
o The seventh and eighth bytes give the Designated VLAN for the
link. The lower 4 bits of the seventh byte give the upper ID bits
of the Designated VLAN and the eighth byte gives the lower VLAN ID
bits. The upper 4 bits of the seventh byte are reserved and MUST
be sent as zero and ignored on receipt.
The VLAN and Flags sub-TLV is carried within the MT-PORT-CAP TLV. It
MUST be carried exactly once in a TRILL IIH PDU. It MUST NOT be
carried within a LAN or a P2P IIH PDU.
2.3.2. Enabled VLANs sub-TLV
The Enabled VLAN sub-TLV specifies the VLANs enabled for end station
service at the port on which the Hello was sent.
+-+-+-+-+-+-+-+-+
|Type=EnabledVLAN|
+-+-+-+-+-+-+-+-+
| Length | (1 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Resv | Start Vlan Id | (2 bytes)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Vlan bit-map....
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
o Type: sub-TLV Type, set to Enabled VLANs sub-TLV 2 [TBD].
o Length: variable, depending on contents described next.
o The minimum size of the value is 3 bytes. The third and
subsequent bytes provide a bit map of enabled VLANs starting at
the VLAN ID indicated in the first two bytes. The lower order
four bits of the first byte give the upper bits of the starting
VLAN ID and the second byte gives the lower bits of that VLAN ID.
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The upper four bits of the first byte are reserved and MUST be
sent as zero and ignored on receipt. The highest order bit of the
third byte indicates the VLAN equal to the starting ID while the
lowest order bit of the third byte indicates that ID plus 7. For
example, VLANs 1 and 14 being enabled for end station service
could be encoded in 4-bytes value 0x00 0x01 0x80 0x04 or,
alternatively, as 0x00 0x00 0x40 0x02.
This sub-TLV may occur more than once in a Hello and a VLAN is
enabled for end station service on the port where the Hello was sent
if this is indicated by any occurrence in the Hello. For example, a
receiver could allocate a 512-byte buffer and, with appropriate
shifting operations, OR in the enabled bits for each subTLV of this
type it finds in a Hello to derive the complete bit map of these
VLANs.
The Enabled VLAN sub-TLV is carried only within the MT-PORT-CAP TLV.
If present, it MUST be carried in TRILL IIH PDU. It MUST NOT be
carried within a LAN IIH or a P2P IIH PDU.
2.3.3. Appointed Forwarders sub-TLV
The Appointed Forwarder sub-TLV provides the mechanism by which the
Designated Intermediate System can inform other Intermediate Systems
on the link that they are the designated VLAN-x forwarder for that
link for one or more ranges of VLAN IDs.
o Type: sub-TLV Type, set to Appointed Forwarders sub-TLV 3 [TBD].
o Length: The size of the value is 6*n bytes where there are n
appointments. Each 6-byte part of the value is formatted as
follows:
+-+-+-+-+-+-+-+-+
|Type=App Frwrdr|
+-+-+-+-+-+-+-+-+
| Length | (1 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Appointment Information (1) | (6 bytes)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ................. |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Appointment Information (N) | (6 bytes)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
o where each appointment information is of the form:
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+---------------------------+
| Appointee Nick | (2 bytes)
+---------------------------+
| Res | Start VLAN ID | (2 bytes)
+---------------------------+
| Res | End VLAN ID | (2 bytes)
+---------------------------+
o The appointed forwarder Intermediate System is specified by its
nickname in the first two bytes.
o The "Res" fields of 4 bits each are reserved and MUST be sent as
zero and ignored on receipt.
The VLAN range given is inclusive. To specify a single VLAN, that
VLAN ID appears as both the start and end VLAN. The Intermediate
System whose nickname is given is appointed forwarder for those VLANs
for which it has end station service enabled (see item 2 above) in
the inclusive range. For example, assume an Intermediate System with
end station service enabled on VLANs 100, 101, 199, and 200 (and
possibly other VLANs less than 100 or greater than 200), but not
enabled for VLANs 102 through 198. It could be appointed forwarder
for these four VLANs through either (1) a single 6-byte value
sequence with start and end VLAN IDs of 100 and 200, or (2) a 12-byte
value sequence with start and end VLAN IDs of 100 and 101 in the
first part and 199 and 200 in the second part.
An Intermediate System's nickname may occur as appointed forwarder
for multiple VLAN ranges within the same or different Port Capability
TLVs within a TRILL Hello. In the absence of appointed forwarder
sub-TLVs referring to a VLAN, the Designated Intermediate System acts
as the appointed forwarder for that VLAN if end station service is
enabled.
The Appointed Forwarder sub-TLV is carried within the MT-PORT-CAP
TLV. If present, it MUST be carried in a TRILL IIH PDU. This MUST
NOT be carried in a LAN IIH PDU or a P2P IIH PDU.
2.3.4. Hop-by-Hop Options (HBHOPT) sub-TLV
By including this sub-TLV within one or more MT aware Port Capability
TLVs in its Hellos, an Intermediate System can advertise the Hop-by-
Hop options it supports on the port through which it sends the Hello.
This sub-TLV may appear zero or more times within a MT aware Port
Capability TLV. By default, in the absence of any HBHOPT sub-TLVs,
no Hop-by-Hop options are supported.
There are two types of Hop-by-Hop option encodings within the TRILL
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Header: bit options and TLV encoded options.
The bit-encoded options supported are indicated by an HBHOPT sub-TLV
of length 3: an initial value byte of 0x00 followed by two bytes in
which each bit indicates that the corresponding bit option is
implemented; in those two bytes the top two bits (0xC000) are
critical option summary bits that all RBridges MUST understand;
therefore support for these bits need not be advertised. Those two
bits are reserved in the HBHOPT sub-TLV and must be sent as zero and
are ignored on receipt.
The implementation of a TLV encoded option is indicated by an HBHOPT
sub-TLV whose value starts with a byte equal to the first byte of the
option. Such HBHOPT sub-TLVs may have additional value bytes further
indicating how the option is supported as specified with the option's
definition, for example a list of supported security algorithms.
+-+-+-+-+-+-+-+-+
| Type = HBHOPT |
+-+-+-+-+-+-+-+-+
| Length | (1 byte)
+-+-+-+-+-+-+-+-+
| Option | (1 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Option dependent variable length information |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
o Type: sub-TLV Type, set to Hop-by-Hop sub-TLV 4 [TBD].
o Length: variable, minimum 1.
o Value: The first byte of the TLV encoded option which must be non-
zero, followed by option dependent information.
2.3.5. Base VLAN-Identifiers sub-TLV
This sub-TLV is added to an IIH PDU to indicate the algorithms for
the VIDs and the Base VIDs and VIDs or Backbone-VIDs (B-VIDs) that
are in use. This information should be the same on all bridges in
the topology identified by MT-PORT-CAP TLV it is being carried.
Discrepancies between neighbours with respect to this sub-TLV are
temporarily allowed but the Base-VID must agree and use a spanning
tree algorithm.
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+-+-+-+-+-+-+-+-+
|Type = B-VID |
+-+-+-+-+-+-+-+-+
| Length | (1 byte)
+-+-+-+-+-+-+-+-+--------------------------------
| ECT - VID Tuple (1) (6 bytes) |
+-----------------------------------------------+
| ......................... |
+-----------------------------------------------+
| ECT - VID Tuples (N) (6 bytes) |
+-----------------------------------------------+
o Type: sub-TLV Type, set to Base-VLAN-ID sub-TLV 5 [TBD].
o Length: The size of the value is ECT-VID Tuples*6 bytes. Each
6-byte part of the ECT-VID tuple is formatted as follows:
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ECT - Algorithm (32 bits) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Base VID (12 bits) |U|M|RES|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
o ECT-ALGORITHM (4 bytes) The ECT-ALGORITHM is advertised when the
bridge supports a given ECT-ALGORITHM (by OUI/Index) on a given
Base VID
o Base VID (12-bits) The Base-VID that is associated with the SPT
Set.
o Use-Flag (1-bit) The Use-flag is set if this bridge, or any bridge
that this bridge sees is currently using this ECTALGORITHM and
Base VID.
o M-Bit (1-bit) The M-bit indicates if this is SPBM or SPBV mode.
The Base VLAN-Identifier sub-TLV is carried within the MT-PORT-CAP
TLV and this is carried in a IIH PDU.
2.3.6. SPB Digest sub-TLV
This sub-TLV is added to an IIH PDU to indicate the digest for
Multiple spanning tree configuration Digests (MCID) and the IS-IS
agreement Digest. This information should be the same on all bridges
in the topology identified by MT-PORT-CAP TLV it is being carried.
These digest indicate when the configuration and the topology are
synchronized and are used to control the updating of forwarding
information. The MCID is controlled solely by configuration and is a
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digest of the allocated VIDs to various protocols. Two MCIDs are
carried to allow transitions when the configuration changes are non-
critical. During the propagation of LSPs the agreement digest will
vary between neighbors until the LSPs are common. During that period
switches or bridges running SPB will not allow multicast forwarding
between neighbors that have differing digests. Discrepancies between
neighbours with respect to this sub-TLV are temporarily allowed but
the Base-VID must agree and use a spanning tree algorithm.
+-+-+-+-+-+-+-+-+
|Type =SPBDigest|
+-+-+-+-+-+-+-+-+
| Length | (1 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MCID (50 Bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Aux MCID (50 Bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Agreement Digest (32 Bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|RES | A | D|
+-+-+-+-+-+-+-+-+
o Type: sub-TLV Type, set to SPB Digest sub-TLV 6 [TBD].
o Length: The size of the value defined below.
o MCID (50-bytes) The complete MCID defined in IEEE 802.1Q which
identifies an SPT Region.
o Aux MCID (50-bytes) The complete MCID defined in IEEE 802.1Q which
identifies an SPT Region. The aux MCID allows SP Regions to be
migrated allocating new VLAN to FID Mappings.
o Agreement Digest (32-bytes) This digest is use to determine when
IS-IS is synchronized between neighbors.
o A (2 bits) The agreement number 0-3 which aligns with BPDUs
agreement number concept. When the Agreement Digest for this node
changes this number is updated and sent in the hello.
o D (2 bits) The discarded agreement number 0-3 which aligns with
BPDUs agreement number concept. When the Agreement Digest for
this node changes this number is updated. Once an Agreement has
been sent it is considered outstanding until a matching or more
recent Discarded Agreement Number is received.
The SPB Digest sub-TLV is carried within the MT-PORT-CAP TLV and this
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is carried in a IIH PDU.
2.3.7. Site Identifier sub-TLV
The site identifier sub-TLV carries information about the site this
device belongs to.
+-+-+-+-+-+-+-+-+
|Type = SiteCap |
+-+-+-+-+-+-+-+-+
| Length | (1 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| System ID (6 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Cluster ID (2 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags (1 byte)|
+-+-+-+-+-+-+-+-+
o Type: sub-TLV Type, set to Site Identifier sub-TLV 250 [TBD].
o Length: The size of the value.
o System Id: The system-id of the site.
o Cluster Id: The cluster-id within the site.
o Flags: Indicates unicast reachability.
The Site Capability sub-TLV is carried within the MT-PORT-CAP TLV and
this is carried in a Hello PDU.
2.3.8. Site Group IPv4 sub-TLV
+-+-+-+-+-+-+-+-+
|Type=SiteGrpIP |
+-+-+-+-+-+-+-+-+
| Length | (1 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv4 address (4 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| .................. |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv4 address (4 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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o Type: sub-TLV Type, set to Site Group IP sub-TLV 251 [TBD].
o Length: The size of the value.
o Value: The list of IPv4 addresses used by the site.
The Site Group IP sub-TLV is carried within the MT-PORT-CAP TLV and
this is carried in a Hello PDU.
2.3.9. Site Group IPv6 sub-TLV
+-+-+-+-+-+-+-+-+
|Type=SiteGrpIPv6|
+-+-+-+-+-+-+-+-+
| Length | (1 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv6 address (16 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| .................. |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv6 address (16 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
o Type: sub-TLV Type, set to Site Group IPv6 sub-TLV 252 [TBD].
o Length: The size of the value.
o Value: The list of IPv6 addresses used by the site.
The Site Group IPv6 sub-TLV is carried within the MT-PORT-CAP TLV and
this is carried in a Hello PDU.
2.3.10. Adjacency Server IPv4 sub-TLV
+-+-+-+-+-+-+-+-+
|Type = ASIPv4 |
+-+-+-+-+-+-+-+-+
| Length | (1 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv4 address (4 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags(1 byte)|
+-+-+-+-+-+-+-+-+
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o Type: sub-TLV Type, set to Adjacency Server IP sub-TLV 253 [TBD].
o Length: The size of the value.
o Value: The list of IPv4 addresses used by the site.
o Flags: Indicates unicast reachability.
The Adjacency Server IP sub-TLV is carried within the MT-PORT-CAP TLV
and this is carried in a Hello PDU.
2.3.11. Adjacency Server IPv6 sub-TLV
+-+-+-+-+-+-+-+-+
|Type = ASIPv6 |
+-+-+-+-+-+-+-+-+
| Length | (1 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv6 address (16 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags(1 byte)|
+-+-+-+-+-+-+-+-+
o Type: sub-TLV Type, set to Adjacency Server IPv6 sub-TLV 254
[TBD].
o Length: The size of the value.
o Value: The list of IPv6 addresses used by the site.
o Flags: Indicates unicast reachability.
The Adjacency Server IPv6 sub-TLV is carried within the MT-PORT-CAP
TLV and this is carried in a Hello PDU.
2.4. Sub-TLVs for the Router Capability TLV
The Router Capability TLV is an optional TLV [RFC 4971] that may be
generated by the originating Intermediate System. We specify these
additional sub-TLVs that can be carried in it. These sub-TLVs
announce the capabilities of the Intermediate System to the entire
IS-IS routing domain.
2.4.1. The TRILL Version sub-TLV
The TRILL Version (TRILL-VER) sub-TLV indicates support of TRILL
Versions. The device announces the maximum version of TRILL, it is
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capable of supporting, including lower versions. In the event, this
sub-TLV is missing, this implies that the node can only support the
base version of the protocol.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | Reserved | Max-version |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
o Type: sub-TLV Type, set to 5 (TRILL-VER).
o Length: 2 - Total number of bytes contained in the value.
o Reserved: Set to zero on transmission and ignored on receipt.
o Max-version: Set to application dependent values.
2.4.2. The Nickname sub-TLV
The Nickname (NICKNAME) sub-TLV carries information about the
nicknames of the advertising device, along with information about its
priority to hold those nicknames. The Nickname sub-TLV MUST be
carried within a Router CAPABILITY TLV in a level-1 LSP generated by
the originating IS. Multiple instances of this sub-TLV are allowed
to be carried.
+-+-+-+-+-+-+-+-+
|Type = NICKNAME|
+-+-+-+-+-+-+-+-+
| Length | (1 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| NICKNAME RECORDS (1) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ................. |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| NICKNAME RECORDS (N) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
where each nickname record is of the form:
+-+-+-+-+-+-+-+-+-+
|Nickname Priority| (1 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tree Root Priority | (2 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Nickname | (2 bytes)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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o Type: sub-TLV Type, set to 6 (NICKNAME).
o Length: 5*N, where N is the number of nickname records present.
o Nickname Priority: This is an unsigned 8-bit integer that gives
the priority with which this node holds this nickname.
o Tree Root Priority: This is an unsigned 16-bit integer that gives
the value of the priority with which this nickname wants to be the
highest priority root node in the Layer-2 domain.
o Nickname: This is an unsigned 16-bit integer that gives device
identifier or alias.
Each nickname record consists of a one-byte priority set to
application dependent values, two bytes of tree root priority and two
bytes of device identifier or alias (i.e., actual nickname).
2.4.3. The Trees sub-TLV
The Trees sub-TLV MUST occur only once and is carried within the
Router CAPABILITY TLV in a level-1 non-pseudo-node LSP generated by
the originating IS. Each device announces three numbers: the number
of trees it dictates that all other Intermediate Systems in the
campus compute if it is the highest priority tree root; the maximum
number of trees it is able to compute; and the number of distribution
trees it wishes to be able to use in forwarding multi-destination
traffic.
All nodes run the same algorithm as described in [RBRIDGES] and the
elected highest priority tree root dictates the number of
distribution tree roots to be used in the network domain and can
additionally list those roots in the tree roots identifier sub-TLV.
+-+-+-+-+-+-+-+-+
|Type = TREE |
+-+-+-+-+-+-+-+-+
| Length | (1 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Number of trees to compute | (2 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Maximum trees able to compute | (2 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Number of trees to use | (2 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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o Type: sub-TLV Type, set to 7 (TREE).
o Length: 6 : Total number of bytes contained in the value field.
o Number of trees to compute: This is an unsigned 16-bit integer
that gives the requested number of distribution trees for multi-
destination frames that will be in use in the Layer-2 domain, if
this device becomes the highest priority tree root in the domain.
o Maximum number of trees able to compute: This is an unsigned 16-
bit integer that give the maximum number of threes that the
originating IS is able to compute for the campus.
o Number of trees to use: This is an unsigned 16-bit integer that
gives the number of distribution trees the originating IS wishes
to be able to use.
2.4.4. The Tree Identifiers Sub-TLV
The tree identifiers sub-TLV is an ordered list of nicknames. When
originated by the Intermediate System which is the highest priority
tree root, this list is the trees which the other Intermediate
Systems are required to compute. If this information is spread
across multiple sub-TLVs, the starting tree number is used to figure
out the ordered list. It is carried within the Router CAPABILITY TLV
in a level-1 non-pseudo-node LSP and is given as:
+-+-+-+-+-+-+-+-+
|Type=TREE-RT-ID|
+-+-+-+-+-+-+-+-+
| Length | (1 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Starting Tree Number | (2 bytes)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Nickname (K-th root) | (2 bytes)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Nickname (K+1 - th root) | (2 bytes)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Nickname (...) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
o Type: sub-TLV Type, set to 8 (TREE-RT-IDs).
o Length: Total number of bytes contained in the value field.
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 first sub-TLV. The starting value and the length field gives
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the number of nicknames being carried in the sub-TLV. In the
event a tree identifier can be computed from two such sub-TLVs and
are different, then it is assumed that this is a transient
condition that will get cleared.
o Nickname: The nickname on which this tree is based.
2.4.5. The Trees Used Identifiers Sub-TLV
This sub-TLV has the same structure as the Tree Identifiers sub-TLV
specified in the above section. The only difference is that its sub-
TLV type is set to 9 TBD (TREE-USE-IDs) and the trees listed are only
those that the originating intermediate systems wishes to use.
2.4.6. Interested VLANs and Spanning Tree Roots sub-TLV
The value of this sub-TLV consists of a VLAN range, flags, and a
variable length list of spanning tree root bridge IDs. This sub-TLV
may appear zero, one, or many times. The union of the VLAN ranges in
all occurrences MUST be precisely the set of VLANs for which the
originating Intermediate System is appointed forwarder on at least
one port and the VLAN ranges in multiple VLANs sub-TLVs for an
Intermediate System MUST NOT overlap. That is, the intersection of
the VLAN ranges for any pair of these sub-TLVs originated by an
Intermediate System must be null. The value length is 10 + 6*n where
n is the number of root bridge IDs. The TLV layout is as follows:
+-+-+-+-+-+-+-+-+
|Type = INT-VLAN|
+-+-+-+-+-+-+-+-+
| Length | (1 byte)
+---------------+-----+
| Nickname | (2 bytes)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interested VLANS | (8 bytes)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Root Bridges | (6*n bytes)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
o Type: sub-TLV Type, set to 10 (INT-VLAN).
o Length: Total number of bytes contained in the value field.
o Nickname: If this is set to 0, then it applies to all device-ids
generated by the node. It may alternatively be set to a specific
nickname, in the event a node wants to segregate traffic using
multiple device-ids.
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o Interested VLANS: In the Interested VLANs, as shown below, the M4
bit indicates that there is an IPv4 multicast router on a link for
which the originating Intermediate System is appointed forwarder
for every VLAN in the indicated range. The M6 bit indicates the
same for an IPv6 multicast router. The R and Reserved bits MUST
be sent as zero and are ignored on receipt. The VLAN start and
end IDs are inclusive. A range of one VLAN ID is indicated by
setting them both to that VLAN ID value. The Appointed Forwarder
Status Lost Counter is also included here. It 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. It has the following format:
0 1 2 3 4 - 15 16 - 19 20 - 31
+----+----+----+----+------------+----------+------------+
| M4 | M6 | R | R | VLAN start | Reserved | VLAN end |
+----+----+----+----+------------+----------+------------+
| Appointed Forwarder Status Lost Counter |
+----+----+----+----+------------+----------+------------+
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
Intermediate System is appointed forwarder for the VLANs in the
range. This information is learned from BPDUs heard by the
Intermediate System. If MSTP is in use on a link, the root bridge
referred to is the CIST (common and internal spanning tree) root
bridge. (While, of course, only one spanning tree root should be
seen on any particular port, there may be multiple ports in the
same VLAN connected to differed bridged LANs with different
spanning tree roots.) If no spanning tree roots can be seen on
any of the links in any of the VLANs in the range indicated for
which the Intermediate System is appointed forwarder (for example
all such links are point-to-point links to other Intermediate
Systems or to end stations so no BPDUs are received) then the
listed set of spanning tree root IDs will be null.
If there are any two VLANs in the range indicated for which the value
of the M4, or M6 bits or the Appointed Forwarder Status Lost Counter
are different, the sub-TLV is incorrect and must be split into
multiple sub-TLVs each indicating only VLANs with the same M4, M6,
and Appointed Forwarder Status Lost Counter values. If there are any
two VLANs in the range indicated for which the set of root bridge IDs
see on all links for which the Intermediate System is appointed
forwarder for the VLAN are not the same, the sub-TLV is incorrect and
must be split into multiple subTLVs each indicating only VLANs with
the same set of DRB seen root bridge IDs. It is always safe to use
sub-TLVs with a "range" of one VLAN ID but this may be too verbose.
Wherever possible, an implementation SHOULD advertise the update to a
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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.
Systems that receive 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 holddown time 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.
Where a receiving system has two copies of a interested vlan and
spanning tree roots sub-TLV from the same system that have different
settings for a given vlan, the procedure used to choose which copy
shall be used is undefined (refer to RFC 4971, Section 3).
This sub-TLV is carried within the CAPABILITY TLV in a level-1 non-
pseudo-node LSP.
2.4.7. The VLAN Group sub-TLV
The VLAN Group sub-TLV consists of two or more 16-bit fields each of
which has a VLAN ID in the low order 12 bits. The top 4 bits MUST be
sent as zero and ignored on receipt. The first such VLAN ID is the
primary, or may be zero if there is no primary. It is carried within
the CAPABILITY TLV in a level-1 non-pseudo-node LSP and is structured
as follows:
+-+-+-+-+-+-+-+-+
|Type=VLAN-GROUP|
+-+-+-+-+-+-+-+-+
| Length | (1 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Primary VLAN ID (2 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Secondary VLAN ID (2 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| more Secondary VLAN IDs ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
o Type: TLV Type, set to 11 (VLAN-GROUPs).
o Length: Total number of bytes contained in the value field, 4 +
2*n, where n may be 0.
o Primary VLAN-ID: This identifies the primary VLAN-ID.
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o Secondary VLAN-ID: This identifies the secondary VLAN-ID, address
learning is shared at the Intermediate System that announces this
sub-TLV.
This sub-TLV may appear zero, one, or multiple times. It should be
noted that all VLAN ID values described above have a 4 bit reserved
section followed by a 12-bit value. It is carried within the
CAPABILITY TLV.
2.4.8. The Ingress-to-Egress Options (ITEOPT) sub-TLV
By including this sub-TLV within one or more Router Capability TLVs
in its LSPs, an RBridge can advertise the Ingress-to-Egress options
it supports. This sub-TLV may appear zero or more times within a
Router Capability TLV. By default, in the absence of any ITEOPT sub-
TLVs, no Ingress-to-Egress options are supported.
There are two types of Ingress-to-Egress option encoding within the
TRILL Header: bit options and TLV encoded options.
The bit-encoded options supported are indicated by an ITEOPT sub-TLV
of length 3: an initial value byte of 0x00 followed by two bytes in
which each bit indicates that the corresponding bit Ingress-to-Egress
option is implemented.
Other Ingress-to-Egress options are TLV encoded within the TRILL
Header options area. The implementation of a TLV encoded option is
indicated by an ITEOPT sub-TLV whose value starts with a byte equal
to the first byte of the option. Such ITEOPT sub-TLVs may have
additional value bytes further indicating how the option is supported
as specified in the option's definition, for example a list of
supported security algorithms.
+-+-+-+-+-+-+-+-+
| Type = ITEOPT |
+-+-+-+-+-+-+-+-+
| Length | (1 byte)
+-+-+-+-+-+-+-+-+
| Option | (1 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Option dependent variable length information |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
o Type: sub-TLV Type, set to Ingress-to-Egress option sub-TLV 12
[TBD].
o Length: variable, minimum 1.
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o Value: The first byte of the option followed by option dependent
information.
2.4.9. VLAN Mapping (VMAP) sub-TLV
The VLAN Mapping (VMAP) TLV carries information concerning VLAN
mappings configured at the originating IS. VLAN mapping is used when
an RBridge campus is divided into regions such that the same VLAN is
represented by different VLAN IDs in different regions or there is a
VLAN is one region that has no equivalent in another region. Each
port on each of the border RBridges between two or more regions MUST
be configured at to which region each port connects with. The
numbering of regions is an arbitrary choice but all border RBridges
in the campus MUST agree on the number of each region.
+-+-+-+-+-+-+-+-+
| Type = VMAP |
+-+-+-+-+-+-+-+-+
| Length | (1 byte)
+-+-+-+-+-+-+-+-+----------...+
| Mapping 1 | (8 bytes)
+-+-+-+-+-+-+-+------------...
| Mapping N, etc.|
+--------------------------...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Count | From VLAN ID | (2 bytes)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| From Region | (2 bytes)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| RESV | To VLAN ID | (2 bytes)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| To Region | (2 bytes)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
o Type: sub-TLV Type, set to VLAN Mapping sub-TLV 13 [TBD].
o Length: variable, 8*N.
o Value: Specific information on each VLAN mapping as diagrammed
above and specified below:
* Count: If this four bit unsigned integer is zero or 1, then the
mapping of a single VLAN ID is being specified. If it is any
value from 2 through 15, then a block of that many contiguous
VLAN IDs starting with the From VLAN ID is mapped to a block of
that many contiguous VLAN IDs starting with the To VLAN ID.
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* From VLAN ID: This is the VLAN ID that, when received on a port
connect to the From Region on a frame being sent to the To
Region, is mapped to the To VLAN ID. This must be a real VLAN
ID, that is, the values 0x000 and 0xFFF are prohibited.
* From Region: This is the region number, within the campus, such
that frames received on a port connected to that region and
destined to a port connected to the To Region have their VLAN
ID mapped as specified by the From VLAN ID and To VLAN ID
fields.
* RESV: MUST be sent as zero and ignored on receipt.
* To VLAN ID: This is the VLAN ID to be used on frames sent out a
port connected to the To Region if they were received on a port
connected to the From Region with the From VLAN ID; except that
if the To VLAN ID is 0x000 the frame is dropped. The value
invalid VLAN ID 0xFFF is prohibited in this field.
* To Region: This is the region number, within the campus, such
that frames sent on a port connected to this region from a port
connected to the From Region have their VLAN ID mapped as
specified by the From VLAN ID and To VLAN ID fields.
2.5. Multi Topology Aware Capability TLV
This section defines a new optional Intermediate System to
Intermediate System (IS-IS) TLV named MT-CAPABILITY, formed of
multiple sub-TLVs, which allows a router to announce its capabilities
for a particular topology within an IS-IS level or the entire routing
domain. This is different from Router Capability TLV defined in RFC
4971, in the sense, the capabilities announced here are topology
scoped.
The Multi Topology Aware Capability (MT-CAPABILITY) is an optional
IS-IS TLV type 144 [TBD], that may be generated by the originating IS
and has the following format:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Type=MTCAPABTLV| Length |O|R|R|R| Topology Identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| sub-TLVs |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
o Type: TLV Type, set to MT-CAPABILITY TLV 144 [TBD].
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o Length: Total number of bytes contained in the value field,
including the length of the sub-TLVs carried in this TLV.
o O bit: The overload bit that follows the semantics associated with
an overloaded intermediate system.
o Topology Identifier: MT ID is a 12-bit field containing the MT ID
of the topology being announced. This field when set to zero
implies that it is being used to carry base topology information.
In TRILL this value is set to ZERO, however, in IEEE SPB and SPBB,
it may be non-zero.
o sub-TLVs: The MT aware Capabilities TLV value contains sub-TLVs
formatted as described in [RFC5305]. They are defined in the next
sections.
The MT-CAPABILITY TLV MUST be carried only within a LSP PDU. It may
occur multiple times in a LSP PDU.
2.5.1. SPB Instance sub-TLV
The SPB Instance sub-TLV gives the SPSourceID for this node/topology
instance. This is the 20 bit value that is used in the formation of
multicast DA addresses for packets originating from this node/
instance. The SPSourceID occupies the upper 20 bits of the multicast
DA together with 4 other bits (see the SPB 802.1ah multicast DA
address format section).
This sub-TLV SHOULD be carried within the MT-Capability TLV in the
fragment ZERO LSP.
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+-+-+-+-+-+-+-+-+
|Type = SPB-Inst|
+-+-+-+-+-+-+-+-+
| Length | (1 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| CIST Root Identifier (4 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| CIST Root Identifier (cont) (4 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| CIST External ROOT Path Cost (4 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Bridge Priority | (2 bytes)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|R R R R| SPS Flags |V| SPSOURCEID | (4 bytes)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Num of Trees | (1 bytes)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| VLAN-ID (1) Tuples (8 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| VLAN-ID (N) Tuples (8 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ECT-Alg-Len | (1 bytes)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Opaque ECT Algorithm (32 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Opaque ECT Information (variable ) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
where VLAN-ID tuples have the format as:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+
|U|M|A| Res |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ECT - Algorithm (32 bits) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Base VID 12 bits) | SPTVID 12 bits) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
o Type: sub-TLV Type, set to SPB Instance sub-TLV 1 [TBD].
o Length: Total number of bytes contained in the value field.
o CIST Root Identifier (64-bits)The CIST Root Identifier is for SPB
interworking with RSTO and MSTP at SPT RegionBoundaries. This is
an imported value from a Spanning tree.
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o CIST External Root Path Cost (32-bits) The CIST External Root Path
Cost is the cost from the Spanning tree algorithm to the Root.
o Bridge Priority (16-bits) Bridge priority is the 16 bits that
together with the low 6 bytes of the System ID form the Bridge
Identifier. The Bridge Identifier is the Spanning tree compatible
Bridge identifier. This is configured exactly as specified in
IEEE802 [802.1D]. This allows SPB to build a compatible Spanning
tree using link state by combining the Bridge Priority and the
System ID to form the 8 byte Bridge Identifier. The 8 byte Bridge
Identifier is also the input to the 16 pre-defined ECT tie breaker
algorithms.
o V bit (1-Bit) The V bit (SPBM) indicates this SPSourceID is auto
allocated(27.11). If the V bit is clear the SPSourceID has been
configured and must be unique. Allocation of SPSourceID is in
[IEEE 802.1aq]. Bridges running SPBM will allocate an SPSourceID
if they are not configured with an explicit SPSourceID. The V Bit
allows neighbor bridges to determine if the auto allocation was
enabled. In the rare chance of a collision of SPsourceID the
bridge with the highest priority Bridge Identifier will win
conflicts and the lower priority Bridge will be re-allocated or if
the lower priority Bridge is configured it will not be allowed to
joint the SPT Region.
o The SPSOURCEID is a 20 bit value used to construct multicast DA's
as described below for multicast packets originating from the
origin (SPB node) of the link state packet (LSP) that contains
this TLV. More details are in [IEEE 802.1aq].
o Number of Trees (8-bits) The Number of Trees is be set to the
number of [ECT-ALGORITHM, Base-VID plus flags] sub TLV's that
follow. Each ECT-ALGORITHM has an Base VID, an SPVID and some
flags described below. This must be set to at least one ECT.
These define the standard ECTs.
o Each VID Tuple consists of:
* U-Bit (1-bit) The Use flag is set if this bridge is currently
using this ECT-ALGORITHM for I-SIDs it sources or sinks. This
is a bit different than the U-bit found in the Hello, which
will set the Use-Flag if it sees other nodal Use-Flags are set
OR it sources or sinks itself.
* M-Bit (1-bit) The M-bit indicates if this is SPBM or SPBV mode.
* A bit, The A bit (SPB) when set declares this is an SPVID with
auto allocation. The VID allocation logic details are in [IEEE
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802.1aq]. Since SPVIDs are from a small pool of resources
(1000 or less) the chances of collision are high. To allow
auto allocation LSPs are exchanged with the allocated bridge
setting the SPVID to 0.
o ECT-ALG-LEN (1 byte): This gives the length of the ECT Algorithm.
o ECT-ALGORITHM (4-bytes) ECT-ALGORITHM is advertised when the
bridge supports a given ECT-ALGORITHM (by OUI/Index) on a given
VID. This declaration must match the declaration in the Hello PDU
originating from the same bridge. The ECT-ALGORITHM, BASE-VID
should match what is generated in the Hellos of the same node.
The ECT-ALGORITHM, BASE-VIDs pairs can come in any order however.
o Base VID (12-bits) The Base-VID that associated the SPT Set via
the ECT-ALGORITHM.
o SPVID (12-bits) The SPVID is the Shortest Path VID when using SPBV
mode. It is not defined for SPBM Mode and should be 0 in SPBM
mode.
o an opaque ECT Data TLV (type TBD) whose first 32 bits are the ECT-
ALGORITHM which this data applies to.
2.5.2. SPBM Service Identifier and Unicast Address sub-TLV
The SPBM Service Identifier and Unicast Address sub-TLV is used to
introduce service group membership on the originating node and/or to
advertise an additional B-MAC unicast address present on, or
reachable by the node.
+-+-+-+-+-+-+-+-+
|Type = SPBM-SI |
+-+-+-+-+-+-+-+-+
| Length | (1 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| B-MAC ADDRESS (6 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Res. | Base-VID | ( 2 bytes)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|T|R| Reserved | ISID #1 | (1+3 bytes)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|T|R| Reserved | ISID #2 | (1+3 bytes)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|T|R| Reserved | ISID #n | (1+3 bytes)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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o Type: sub-TLV Type, set to SPBM Service Identifier and Unicast
Address sub-TLV 2 [TBD].
o Length: Total number of bytes contained in the value field.
o B-MAC ADDRESS is a unicast address of this node. It may be either
the single nodal address, or may address a port or any other level
of granularity relative to the node. In the case where the node
only has one B-MAC address this should be the same as the SYS-ID
of the node. To add multiple B-MACs this TLV must be repeated per
additional B-MAC.
o ISID #1 .. #N are 24 bit service group membership identifiers. If
two nodes have an ISID in common, intermediate nodes on the unique
shortest path between them will create forwarding state for the
related B-MAC addresses and will also construct multicast
forwarding state using the ISID and the node's SPSOURCEID to
construct a multicast DA as described in IEEE 802.1aq LSB. Each
ISID has a Transmit(T) and Receive(R) bit which indicates if the
membership is as a Transmitter/Receiver or both (with both bits
set). In the case where the Transmit(T) and Receive(R) bits are
both zero, the ISID is ignored. If more ISIDs are associated with
a particular B-MAC than can fit in a single TLV, this TLV can be
repeated with the same B-MAC but with different ISID values.
2.6. Sub-TLVs of the Extended Reachability TLV
This section specifies two new sub-TLVs that appear only within the
Extended Reachability TLV (type 22).
2.6.1. SPB Link Metric sub-TLV
The SPB Link Metric sub-TLV occurs nested as within the Extended
Reachability TLV (type 22), or the Multi Topology Intermediate System
TLV (type 222). If this sub TLV is not present for an ISIS adjacency
then that adjacency MUST NOT carry SPB traffic for the given topology
instance.
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+-+-+-+-+-+-+-+-+
|Type=SPB-Metric|
+-+-+-+-+-+-+-+-+
| Length | (1 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SPB-LINK-METRIC | (3 bytes)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Num of ports | (1 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Port Identifier | ( 2 bytes)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Opaque ECT Algorithm (32 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Opaque ECT Information (variable ) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
o Type: TLV Type, set to SPB Link Metric sub-TLV 5 [TBD].
o Length: Total number of bytes contained in the value field.
o SPB-LINK-METRIC indicates the administrative cost or weight of
using this link as a 24 bit unsigned number. Smaller numbers
indicate lower weights and are more likely to carry SPB traffic.
Only one metric is allowed per SPB instance per link. If multiple
metrics are required multiple SPB instances are required, either
within IS-IS or within several independent IS-IS instances.
o Num of Ports is the number of ports associated with this link.
o Port Identifier is the standard IEEE port identifier used to build
a spanning tree associated with this link.
o an opaque ECT Data TLV (type TBD) whose first 32 bits are the ECT-
ALGORITHM to which this data applies.
2.6.2. MTU sub-TLV
The MTU sub-TLV is used to optionally announce the MTU of a link. It
occurs nested as within the Extended Reachability TLV (type 22).
+-+-+-+-+-+-+-+-+
| Type = MTU |
+-+-+-+-+-+-+-+-+
| Length | (1 byte)
+-+-+-+-+-+-+-+-+
|F| Reserved | (1 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MTU | (2 bytes)
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
o Type: TLV Type, set to MTU sub-TLV 6 [TBD].
o Length: Total number of bytes contained in the value field.
o Failed: This bit is a one if MTU testing on this link failed at
the required campus-wide MTU.
o MTU: This field is set to the largest successfully tested MTU size
for this link or zero if it has not been tested.
2.7. TRILL Neighbor TLV
The TRILL Neighbor TLV is used in the TRILL-Hello PDU in place of the
IS Neighbor TLV. It differs in that MTU information is provided per
neighbor and provision is made for fragmentation, so that not all
neighbors need be reported in each TRILL-Hello, to support the hard
limit on the size of TRILL-Hellos. This TLV can occur zero, one, or
multiple times in a TRILL-Hello PDU. The structure of the TRILL
Neighbor TLV is as follows:
+-+-+-+-+-+-+-+-+
| Type = TNeigh |
+-+-+-+-+-+-+-+-+
| Length | (1 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|S|L| Reserved | (2 bytes)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Neighbor RECORDS (1) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ................. |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Neighbor RECORDS (N) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The list of neighbors MUST be ordered by MAC address, considering
each 6-byte MAC address to be an unsigned integer, starting with the
smallest. The information present for each neighbor is as follows:
+-+-------------------+
|F| Reserved | (2 bytes)
+-+-------------------+
| MTU | (2 bytes)
+--------------------------------------------------------+
| MAC Address | (6 bytes)
+--------------------------------------------------------+
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o Type: TLV Type, set to TRILL-Neighbor TLV XX [TBD].
o Length: Total number of bytes contained in the value field, 2 +
10*n, where n is the number of neighbor records.
o S: smallest flag. If this bit is a one, then the list of
neighbors includes the neighbor with the smallest MAC address.
o L: largest flag. If this bit is a one, then the list of neighbors
includes the neighbor with the largest MAC address.
o Reserved: These bits are reserved for future use and MUST be set
to zero on transmission and ignored on receipt.
o F: failed. This bit is a one if MTU testing to their neighbor
(see Section 3.3) failed at the required campus-wide MTU
o MTU: This field is set to the largest successfully tested MTU size
for this neighbor or zero if it has not been tested.
o MAC Address: The MAC address of the neighbor as in the IS Neighbor
RLV (#6).
2.8. The Group Membership Active Source TLV
The Group Active Source (GMAS) TLV is IS-IS TLV type 146 [TBD] and
has the following format:
+-+-+-+-+-+-+-+-+
| Type = GMAS | (1 byte)
+-+-+-+-+-+-+-+-+
| Length | (1 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| sub-TLVs (variable bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
o Type: TLV Type, set to GMAS-TLV 146 [TBD].
o Length: Total number of bytes contained in the value field, which
includes the length of the sub-TLVs carried in this TLV.
o sub-TLVs: The Group Active Source TLV value contains sub-TLVs
formatted as described in [RFC5305]. The sub-TLVs for this TLV
are specified in the following subsections.
The GMAS TLV is carried within Multicast Group Level 1 link state
PDU.
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2.8.1. The Group MAC Active Source sub-TLV
The Group MAC Source (GMAS-MAC) sub-TLV is IS-IS sub-TLV type 1
within the GMAS TLV and has the following format:
+-+-+-+-+-+-+-+-+
| Type=GMAS-MAC | (1 byte)
+-+-+-+-+-+-+-+-+
| Length | (1 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|D|D| R | Vlan ID | (2 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Address family | (2 bytes)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Length | (1 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Delivery group (afi scoped number of bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Delivery Source (afi scoped number of bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Num Group Recs | (1 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| GROUP RECORDS (1) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ................. |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| GROUP RECORDS (N) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
where each group record is of the form:
+-+-+-+-+-+-+-+-+
| RESERVED | (1 byte)
+-+-+-+-+-+-+-+-+
| Num of Sources| (1 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Group Address (6 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Source 1 Address (6 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Source 2 Address (6 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Source M Address (6 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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o Type: sub-TLV Type, set to 1 (GMAS-MAC) of length 1 byte.
o Length: Total number of bytes contained in the value field.
o Confidence: This carries an 8-bit quantity indicating the
confidence level in the MAC addresses being transported. Whether
this field is used, and its semantics if used, are further defined
by the specific protocol using Layer-2-IS-IS. If not used, it
MUST be set to zero on transmission and be ignored on receipt.
o Topology-Id/Nickname : Depending on the technology in which it is
used, this carries the topology-id or nickname. When this field
is set to zero this implies that the MAC addresses are reachable
across all topologies or across all nicknames of the originating
IS.
o RESERVED: Must be sent as zero on transmission and is ignored on
receipt.
o G: Delivery Group is set
o S: Delivery Source is set
o VLAN-ID: This carries a 12-bit VLAN identifier that is valid for
all subsequent MAC addresses in this TLV, or the value zero if no
VLAN is specified.
o Number of Group Records: This is of length 1 byte and lists the
number of group records in this TLV.
o Group Record: Each group record has a one byte reserved space and
the next byte carries the number of sources. It then has a 48-bit
multicast Group Address followed by 48-bit source MAC addresses.
An address being a group multicast address or unicast source
address can be checked using the multicast bit in the address. 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 Active Source TLV.
The GMAS-MAC sub-TLV is carried within the GMAS TLV and MUST be
carried in a standard Level 1 link state MGROUP PDU.
2.8.2. The Group IP Active Source sub-TLV
The Group IP Address (GMAS-IP) sub-TLV is IS-IS TLV type 2 and has
the following format:
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+-+-+-+-+-+-+-+-+
| Type=GMAS-IP | (1 byte)
+-+-+-+-+-+-+-+-+
| Length | (1 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|D|D| R | Vlan ID | (2 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Address family | (2 bytes)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Length | (1 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Delivery group (afi scoped number of bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Delivery Source (afi scoped number of bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Num Group Recs | (1 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| GROUP RECORDS (1) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ................. |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| GROUP RECORDS (N) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
where each group record is of the form:
+-+-+-+-+-+-+-+-+
| RESERVED | (1 byte)
+-+-+-+-+-+-+-+-+
| Num of Sources| (1 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Group Address (4 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Source 1 Address (4 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Source 2 Address (4 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Source M Address (4 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
o Type: sub-TLV Type, set to 2 (GIP-ADDR).
o Length: Total number of bytes contained in the value field of the
TLV.
o Confidence: This carries an 8-bit quantity indicating the
confidence level in the IP addresses being transported. Whether
this field is used, and its semantics if used, are further defined
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by the specific protocol using Layer-2-IS-IS. If not used, it
must be set to zero on transmission and be ignored on receipt.
o Topology-Id/Nickname : Depending on the technology in which it is
used, this carries the topology-id or nickname. When this field
is set to zero this implies that the MAC addresses are reachable
across all topologies or across all nicknames of the originating
IS.
o RESERVED: Must be sent as zero on transmission and is ignored on
receipt.
o G: Delivery Group is set
o S: Delivery Source is set
o VLAN-ID: This carries a 12-bit VLAN identifier that is valid for
all subsequent MAC addresses in this TLV, or the value zero if no
VLAN is specified.
o Number of Group Records: This is of length 1 byte and lists the
number of group records in this TLV.
o Group Record: Each group record has a one byte reserved space and
the next byte carries the number of sources. It is followed by a
32-bit IPv4 Group Address followed by 32-bit 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 repeated in another sub-TLV of another
instance of the Group Active Source TLV.
The GMAS-IP TLV is carried within the GMAS TLV and MUST be carried in
a standard Level 1 link state MGROUP PDU.
2.8.3. The Group IPv6 Active Source sub-TLV
The Group IPv6 Active Source (GMAS-IPv6) TLV is IS-IS sub-TLV type 3
and has the following format:
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+-+-+-+-+-+-+-+-+
| Type=GMAS-IP | (1 byte)
+-+-+-+-+-+-+-+-+
| Length | (1 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|D|D| R | Vlan ID | (2 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Address family | (2 bytes)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Length | (1 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Delivery group (afi scoped number of bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Delivery Source (afi scoped number of bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Num Group Recs | (1 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| GROUP RECORDS (1) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ................. |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| GROUP RECORDS (N) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
where each group record is of the form:
+-+-+-+-+-+-+-+-+
| RESERVED | (1 byte)
+-+-+-+-+-+-+-+-+
| Num of Sources| (1 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Group Address (16 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Source 1 Address (16 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Source 2 Address (16 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Source M Address (16 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
o Type: sub-TLV Type, set to 3 (GIPV6-ADDR).
o Length: Total number of bytes contained in the value field.
o Confidence: This carries an 8-bit quantity indicating the
confidence level in the IPv6 addresses being transported. Whether
this field is used, and its semantics if used, are further defined
by the specific protocol using Layer-2-IS-IS. If not used, it
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must be set to zero on transmission and be ignored on receipt.
o Topology-Id/Nickname : Depending on the technology in which it is
used, this carries the topology-id or nickname. When this field
is set to zero this implies that the MAC addresses are reachable
across all topologies or across all nicknames of the originating
IS.
o RESERVED: Must be sent as zero on transmission and is ignored on
receipt.
o G: Delivery Group is set
o S: Delivery Source is set
o VLAN-ID: This carries a 12-bit VLAN identifier that is valid for
all subsequent MAC addresses in this TLV, or the value zero if no
VLAN is specified.
o Number of Group Records: This of length 1 byte and lists the
number of group records in this TLV.
o Group Record: Each group record has a one byte reserved space and
the next byte carries the number of sources. It is followed by a
128-bit multicast IPv6 Group Address followed by 128-bit 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 repeated in another sub-TLV in
another instance of the Group Address TLV.
The GMAS-IPv6 sub-TLV is carried within the GMAS TLV and MUST be
carried in a standard Level 1 link state MGROUP PDU.
2.9. PDU Extensions to IS-IS
2.9.1. The Multicast Group PDU
The systems that this document is concerned with want to carry not
only layer-2 unicast information in the link state protocols, but
also multicast information. This section specifies three new IS-IS
PDUs, the Multicast Group (MGROUP) PDU, for carrying a list of
attached or joined multicast groups. The Multicast Group Complete
Sequence Number (MGROUP-CSNP) PDU and the Multicast Group Partial
Sequence Number (MGROUP-PSNP) PDU packets are also defined to be used
with the new MGROUP-PDU to perform database exchange on the MGROUP
PDU packets.
In the Layer-2 environment, it is expected the join/leave frequency
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of the multicast members will be much higher than unicast topology
changes. It is efficient to separate the updates for the group
membership change information from the remainder of the information
by placing this information in a separate PDU. This enables
reachability information, that would trigger an SPF, to be not
impacted at all. Furthermore, during SPF runs, TLVs being on
different PDUs which do not affect SPF need not be inspected during
processing.
The choice of a different PDU also opens the LSP-space to another 256
fragments to carry a large number of groups. This additional space
can be used judiciously to carry only multicast information.
The Multicast Group (MGROUP) PDU can be used to advertise a set of
attached, or joined, multicast groups. The MGROUP PDU is formatted
identical to a Level 1 Link State PDU, as described in Section 9.3 of
[IS-IS]. One field, PDU Type, is changed to 19 [TBD], to signify
this PDU is carrying multicast group information, rather than unicast
reachability information.
The Multicast Group PDU carries TLVs indicating multicast membership
information. There are three sub-TLVs of the GADDR TLV defined in
this document, that MAY be present in this PDU, namely, GMAC-ADDR,
GIP-ADDR, and GIPV6-ADDR TLVs.
One or more TLVs MAY be carried in a single MGROUP PDU. Future
multicast address TLVs MAY be defined using other type codes, and be
carried in an MGROUP PDU.
The information carried in this PDU is processed in a similar fashion
as described in [RFC 1584].
2.9.1.1. The Multicast Group Partial Sequence Number PDU
The Multicast Group Partial Sequence Number (MGROUP-PSNP) PDU is used
to reliably flood the MGROUP PDU following the base protocol
specifications.
2.9.1.2. The Multicast Group Complete Sequence Number PDU
The Multicast Group Complete Sequence Number PDU (MGROUP-CSNP) PDU is
used to reliably flood the MGROUP PDU following the base protocol
specifications.
2.9.1.3. Enhancements to the flooding process
This document specifies that the information contained in the MGROUP-
PDU is in a parallel database and its update mechanisms mimic that of
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the regular database. Nodes running IS-IS in an L2 domain MUST
support these additional MGROUP PDUs defined in this document. In
general, the flooding of the MGROUP-PDU in tandem with the MGROUP-
PSNP and MGROUP-CSNP PDUs uses the same update procedures as defined
for the regular LSP, PSNP, and CSNP PDUs.
For example, on P2P links CSNP is exchanged on the formation of an
adjacency. In a similar fashion a MGROUP-CSNP MUST also be exchanged
between the neighbors at the same time. This gets the initial
MGROUP-database synchronization going. After this similar actions of
the base protocol specifications for the regular database
synchronization will be maintained to keep the MGROUP-database
synchronized.
Similarly, on LAN links the DIS is responsible for sending periodic
CSNP transmissions. The DIS in the L2 IS-IS network domain will also
be responsible for sending periodic MGROUP-CSNP transmissions. The
update and flooding process will work in parallel for the two
databases and there is no further synchronization between them.
In general, the database synchronization is performed in parallel
with no interactions between the messages. However, the initial
triggers that start a CSNP exchange are correlated, in the sense it
also triggers a MGROUP-CSNP exchange. For example, during graceful
restart [RFC 5306], the normal hello operations as described in the
RFC will be followed. The enhancements will take place such that
CSNP and PSNP triggers will necessitate a parallel MGROUP-CSNP and
MGROUP-PSNP exchange and update process will be triggered in parallel
for the MGROUP-PDUs. After both databases containing the regular
PDUs and MGROUP-PDUs have been obtained, the restart process is
deemed complete.
2.9.1.4. Enhancements to the maximum sequence number reached
In the event, LSPs reach the maximum sequence number, ISO/IEC 10589
states the rules for the process to shut down and its duration. With
the introduction of the MGROUP-PDU, the same process now applies when
LSPs from either database reach the maximum sequence number.
2.9.2. The TRILL-Hello PDU
A different Hello PDU is required for TRILL links because it is
necessary that a single Designated RBridge (DIS) be elected on each
link based just on priority and MAC address regardless of two-way
connectivity. However, RBridge reachability is reported by RBridges
in their LSP on the same basis as layer 3 Intermediate Systems report
reachability, that is, if and only if two-way connectivity exists.
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The TRILL-Hello PDU has the same general structure as an IS-IS LAN
PDU. An RBridge (an Intermediate System supporting TRILL) sends this
PDU, with the same timing as the IS-IS LAN Hello PDU. More
specifically, in a TRILL-Hello PDU the IS-IS Common Header and the
fixed PDU Header are the same as a Level 1 IS-IS LAN Hello except
that a new PDU Type number is used as listed in Section 7. The
circuit type field, of course, is always equal to one. A TRILL-Hello
PDU SHOULD not be padded and MUST NOT exceed a length limit equal to
42 bytes shorter than the reasonable lower bound for the link MTU.
For example, for an 802.3 Ethernet link, the MTU SHOULD be assumed to
be 1512 bytes for the purpose of determining the maximum size of
TRILL-Hello PDUs on that link. Thus, for such a link, TRILL-Hellos
MUST NOT exceed 1470 bytes.
The following MUST appear in every TRILL-Hello PDU: a Port Capability
TLV (see Section 2.3) containing a Special VLANs and Flags sub-TLV.
Additional TLVs/sub-TLVs MAY appear in a TRILL-Hello including the
TRILL Neighbor TLV specified in Section 2.7 and the following sub-
TLVs specified in Section 2.3: Enabled VLANs sub-TLV, Appointed
Forwarders sub-TLV, and Hop-by-Hop Options sub-TLV.
The Padding TLV (#8) SHOULD NOT appear in a TRILL-Hello.
The IS-IS Neighbor TLV (#6) MUST NOT appear in a TRILL-Hello.
Instead, it uses the TRILL Neighbor TLV (see Section 2.7).
2.9.3. The MTU PDU
The MTU-probe and MTU-ack PDUs are used to determine the MTU on a
link between intermediate systems. An MTU-probe MUST be padded to
the size being tested with the Padding TLV (#8). The ability to send
an MTU-probe PDU is optional but an Intermediate System that supports
TRILL MUST send an MTU-ack in response to an MTU-probe and that MTU-
ack MUST be padded to the size of the MTU-probe.
The MTU PDUs have the standard IS-IS common header with two new PDU
Type numbers, one each, as listed in Section 7. They also have a 20-
byte common fixed MTU PDU header as shown below.
+------------+
| PDU Length | (2 bytes)
+------------+-------------------------+
| Probe ID | (6 bytes)
+--------------------------------------+
| Probe Source ID | (6 bytes)
+--------------------------------------+
| Ack Source ID | (6 bytes)
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+--------------------------------------+
As with other IS-IS PDUs, the PDU length contains length of the
entire IS-IS packet starting with and including the IS-IS common
header.
The Probe ID field is an arbitrary 48-bit quantity set by the
Intermediate System issuing an MTU-probe and copied by the responding
system into the corresponding MTU-ack. For example, an Intermediate
System 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 Intermediate system issuing an MTU-
probe to its System ID and copied by the responding system into the
corresponding MTU-ack.
The Ack Source ID is set to zero in MTU-probe PDUs. An Intermediate
System issuing an MTU-ack set this field to its System ID.
The TLV area follows the MTU PDU header area. This area MAY contain
an Authentication TLV and MUST be padded to the size being tested
with the Padding TLV.
3. Acknowledgements
The authors would like to thank Les Ginsberg and Mike Shand for their
useful comments.
4. Security Considerations
This document adds no additional security risks to IS-IS, nor does it
provide any additional security for IS-IS.
5. IANA Considerations
This document creates six new PDU types, namely the MCAST PDU, MCAST-
CSNP PDU, the MCAST-PSNP PDU, TRILL-HELLO-PDU, MTU-PROBE-PDU, and
MTU-ACK-PDU. IANA SHOULD assign a new PDU type to the level-1 PDUs
described above and reflect it in the PDU registry.
MCAST-PDU Level-1 PDU Type: 19
MCAST-CSNP-PDU Level-1 PDU Type: 22
MCAST-PSNP-PDU Level-1 PDU Type: 29
TRILL-HELLO-PDU Level-1 PDU Type: 21
MTU-PROBE-PDU Level-1 PDU Type: 23
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MTU-ACK-PDU Level-1 PDU Type: 28
This document specifies the definition a set of new IS-IS TLVs, the
MAC-Reachability TLV (type 141), the Group Address TLV (type 142),
the Port-Capability TLV (type 143), the MT-Capability TLV (type 144),
and the Trill-Neighbor TLV (type 145), and Group Member Active Source
TLV (type 146) that needs to be reflected in the IS-IS TLV code-point
registry.
This document creates a number of new sub-TLVs in the numbering space
for the Group Address TLV, the MT Port Capability TLV, the Extended
Reachability TLV, the MT-Capability TLV, and the Capability TLV. The
TLV and sub-TLVs are given below along with technologies that use
them.
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IIH LSP SNP MCAST MCAST TRILL/
LSP SNP IEEE
MAC-RI TLV (141) - X - - - T/I
GADDR-TLV (142) - - - X - -/I
GADDR-TLV.GMAC-ADDR sub-TLV 1 - - - X - T/I
GADDR-TLV.GMAC-IP sub-TLV 2 - - - X - T/I
GADDR-TLV.GMAC-IPV6 sub-TLV 3 - - - X - T/I
GADDR-TLV.SPBV-MAC-ADDR sub-TLV 4 - - - X - -/I
MT-Port-Cap-TLV (143) X - - - - T/-
PortCap.VLAN and Flags sub-TLV 1 X - - - - T/-
PortCap.Enabled-VLANs sub-TLV 2 X - - - - T/-
PortCap.AppointedFwrdrs sub-TLV 3 X - - - - T/-
PortCap.HBHOPT sub-TLV 4 X - - - - T/-
PortCap.BaseVLANID sub-TLV 5 X - - - - -/I
PortCap.SPBDigest sub-TLV 6 X - - - - -/I
PortCap.SiteIdentifier sub-TLV 250 X - - - - -/-
PortCap.SiteGroupIP sub-TLV 251 X - - - - -/-
PortCap.SiteGroupIPv6 sub-TLV 252 X - - - - -/-
PortCap.AdjServerIP sub-TLV 253 X - - - - -/-
PortCap.AdjServerIPv6 sub-TLV 254 X - - - - -/-
CAPABILITY.Trill-Version sub-TLV 5 - X - - - T/-
CAPABILITY.Nickname sub-TLV 6 - X - - - T/-
CAPABILITY.Tree sub-TLV 7 - X - - - T/-
CAPABILITY.Tree Id sub-TLV 8 - X - - - T/-
CAPABILITY.TreeUseRootId sub-TLV 9 - X - - - T/-
CAPABILITY.Int-VLANs sub-TLV 10 - X - X - T/-
CAPABILITY.VLAN-Groups sub-TLV 11 - X - - - T/-
CAPABILITY.ITEOPT sub-TLV 12 - X - - - T/-
CAPABILITY.VMAP sub-TLV 13 - X - - - T/-
MT-Capability-TLV (144) - X - - - -/I
MT-Cap.SPB Instance sub-TLV 1 - X - - - -/I
MT-Cap.Service Id. sub-TLV 2 - X - - - -/I
TRILL-Nieghbor TLV (145) X - - - - T/-
EXT-IS.SPB Link Metric sub-TLV 5 - X - - - -/I
EXT-IS.MTU sub-TLV 6 - X - - - T/-
MT-EXT-IS.SPB LinkMetric sub-TLV 5 - X - - - -/I
Group Mem Active Source TLV (146) - - - X - -/-
GMAS-TLV.GMAS-MAC sub-TLV 1 - - - X - -/-
GMAS-TLV.GMAS-IP sub-TLV 2 - - - X - -/-
GMAS-TLV.GMAS-IPV6 sub-TLV 3 - - - X - -/-
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IANA SHOULD manage the remaining space using the IETF Review method
[RFC 5226].
6. Contributing Authors
David Ward
Juniper Networks
1194 N. Mathilda Ave.
Sunnyvale, California 94089-1206 USA
Phone: +1-408-745-2000
Email: dward@juniper.net
Russ White
Cisco Systems
170 W Tasman Drive
San Jose, CA 95138
US
Email: riw@cisco.com
Dino Farinacci
Cisco Systems
170 W Tasman Drive
San Jose, CA 95138
US
Email: dino@cisco.com
Radia Perlman
Intel Labs
2200 Mission College Blvd.
Santa Clara, CA 95054-1549
US
Phone: +1-408-765-8080
Email: Radia@alum.mit.edu
Donald E. Eastlake 3rd
Stellar Switches
155 Beaver Street
Milford, MA 07157
US
Phone: +1-508-333-2270
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Email: d3e3e3@gmail.com
Peter Ashwood-Smith
Huawei Technologies Canada Co. Ltd.
411 Legget Drive, Suite 503
Kanta, Ontario K2K 3C9
CANADA
Email: Peter.AshwoodSmith@huawei.com
Don Fedyk
Alcatel-Lucent
220 Hayden Road
Groton, MA 01450
US
Email: Donald.Fedyk@alcatel-lucent.com
7. References
7.1. Normative References
[IS-IS] ISO/IEC 10589, "Intermediate System to Intermediate System
Intra-Domain Routing Exchange Protocol for use in
Conjunction with the Protocol for Providing the
Connectionless-mode Network Service (ISO 8473)", 2005.
[RFC 1195]
Callon, R., "Use of OSI IS-IS for Routing in TCP/IP and
Dual Environments", 1990.
[RFC 4971]
Vasseur, JP. and N. Shen, "Intermediate System to
Intermediate System (IS-IS) Extensions for Advertising
Router Information", 2007.
[RFC 5305]
Li, T. and H. Smit, "IS-IS Extensions for Traffic
Engineering", 2008.
[RFC 5306]
Shand, M. and L. Ginsberg, "Restart Signaling for
Intermediate System to Intermediate System (IS-IS)", 2004.
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7.2. Informative References
[IEEE 802.1aq]
"Standard for Local and Metropolitan Area Networks /
Virtual Bridged Local Area Networks / Amendment 9:
Shortest Path Bridging, Draft IEEE P802.1aq/D1.5", 2008.
[RBRIDGES]
Perlman, R., Eastlake, D., Dutt, D., Gai, S., and A.
Ghanwani, "RBridges: Base Protocol Specification", 2010.
[RFC 1584]
Moy, J., "Multicast Extensions to OSPF", March 1994.
Author's Address
Ayan Banerjee (editor)
Cisco Systems
170 W Tasman Drive
San Jose, CA 95138
US
Email: ayabaner@cisco.com
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