Network Working Group A. Banerjee
Internet-Draft Cisco Systems
Intended status: Standards Track D. Ward
Expires: May 27, 2011 Juniper Networks
November 23, 2010
Extensions to IS-IS for Layer-2 Systems
draft-ietf-isis-layer2-08
Abstract
This document specifies the IS-IS extensions necessary to support
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. Furthermore, the TLVs described
in this document are generic layer 2 additions and specific ones as
needed are defined in the IS-IS technology specific extensions. 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 in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on May 27, 2011.
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
Provisions Relating to IETF Documents
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publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
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to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
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described in the Simplified BSD License.
Table of Contents
1. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
2. TLV Enhancements to IS-IS . . . . . . . . . . . . . . . . . . 4
2.1. The MAC-Reachability TLV . . . . . . . . . . . . . . . . . 4
2.2. Multi Topology aware Port Capability TLV . . . . . . . . . 5
3. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 6
4. Security Considerations . . . . . . . . . . . . . . . . . . . 7
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
6. References . . . . . . . . . . . . . . . . . . . . . . . . . . 9
6.1. Normative References . . . . . . . . . . . . . . . . . . . 9
6.2. Informative References . . . . . . . . . . . . . . . . . . 9
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 10
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1. Overview
There are a number of systems (for example, [RBRIDGES], [802.1aq],
[OTV]) that use layer 2 addresses carried in a link state routing
protocol, specifically IS-IS [IS-IS] [RFC1195], to provide true layer
2 routing. In almost all the technologies mentioned above, classical
Layer 2 packets are encapsulated with an outer header. The outer
header format varies across all these technologies. This outer
header is used to route the encapsulated packets to their
destination.
In this document we specify a set of TLVs to be added to [IS-IS]
level 1 PDUs, to support these proposed systems. The TLVs are
generic layer 2 additions and specific ones as needed are defined in
the IS-IS technology specific extensions. This draft does not
propose any new forwarding mechanisms using this additional
information carried within IS-IS.
1.1. Terminology
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.
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2. TLV Enhancements to IS-IS
In this section we specify the enhancements for the TLVs that are
needed in common 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:
+-+-+-+-+-+-+-+-+
| 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 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 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 RESV: Must be sent as zero on transmission and is ignored on
receipt.
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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. The manner in which these TLVs
are generated by the various Layer 2 routing technologies, and the
manner they are consumed are detailed in the technology specific
documents.
In most of the technologies, these MAC-RI TLVs will translate to
populating the hardware with these entries with appropriate next-hop
information as derived from the advertising IS.
2.2. 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 |R|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 R: Reserved, MUST be sent as zero on transmission and is ignored
on receipt.
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.
o sub-TLVs: The MT aware Port Capabilities TLV value contains sub-
TLVs formatted as described in [RFC5305]. They are defined in the
technology scoped documents.
The MT-PORT-CAP TLV may occur multiple times, and is carried only
within a IIH PDU.
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3. Acknowledgements
The authors would like to thank Peter Ashwood-Smith, Donald E.
Eastlake 3rd, Dino Farinacci, Don Fedyk, Les Ginsberg, Radia Perlman,
Mike Shand, and Russ White for their useful comments.
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4. Security Considerations
This document adds no additional security risks to IS-IS, nor does it
provide any additional security for IS-IS.
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5. IANA Considerations
This document specifies the definition of a set of new IS-IS TLVs,
the MAC-Reachability TLV (type 141), and the Port-Capability TLV
(type 143) that needs to be reflected in the IS-IS TLV code-point
registry.
IIH LSP SNP
MAC-RI TLV (141) - X -
MT-Port-Cap-TLV (143) X - -
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6. References
6.1. Normative References
[IS-IS] ISO/IEC 10589:2002, Second Edition, "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)", 2002.
[RFC 1195]
Callon, R., "Use of OSI IS-IS for Routing in TCP/IP and
Dual Environments", 1990.
6.2. 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.
[OTV] Grover, H., Farinacci, D., and D. Rao, "OTV: Overlay
Transport Virtualization", draft-hasmit-otv-00, 2010.
[RBRIDGES]
Perlman, R., Eastlake, D., Dutt, D., Gai, S., and A.
Ghanwani, "RBridges: Base Protocol Specification", 2010.
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Authors' Addresses
Ayan Banerjee
Cisco Systems
170 W Tasman Drive
San Jose, CA 95138
US
Email: ayabaner@cisco.com
David Ward
Juniper Networks
1194 N. Mathilda Ave.
Sunnyvale, CA 94089-1206
USA
Phone: +1-408-745-2000
Email: dward@juniper.net
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