< draft-ietf-isis-node-admin-tag-01.txt   draft-ietf-isis-node-admin-tag-02.txt >
IS-IS for IP Internets P. Sarkar, Ed. IS-IS for IP Internets P. Sarkar, Ed.
Internet-Draft H. Gredler Internet-Draft H. Gredler
Intended status: Standards Track S. Hegde Intended status: Standards Track S. Hegde
Expires: September 10, 2015 Juniper Networks, Inc. Expires: December 3, 2015 Juniper Networks, Inc.
S. Litkowski S. Litkowski
B. Decraene B. Decraene
Orange Orange
Z. Li Z. Li
Huawei Technologies Huawei Technologies
E. Aries E. Aries
R. Rodriguez R. Rodriguez
Facebook Facebook
H. Raghuveer H. Raghuveer
March 9, 2015 June 1, 2015
Advertising Per-node Admin Tags in IS-IS Advertising Per-node Admin Tags in IS-IS
draft-ietf-isis-node-admin-tag-01 draft-ietf-isis-node-admin-tag-02
Abstract Abstract
This document describes an extension to IS-IS protocol [ISO10589], This document describes an extension to IS-IS protocol [ISO10589],
[RFC1195] to add an optional operational capability, that allows [RFC1195] to add an optional operational capability, that allows
tagging and grouping of the nodes in an IS-IS domain. This allows tagging and grouping of the nodes in an IS-IS domain. This allows
simple management and easy control over route and path selection, simple management and easy control over route and path selection,
based on local configured policies. based on local configured policies.
This document describes the protocol extensions to disseminate per- This document describes the protocol extensions to disseminate per-
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on September 10, 2015. This Internet-Draft will expire on December 3, 2015.
Copyright Notice Copyright Notice
Copyright (c) 2015 IETF Trust and the persons identified as the Copyright (c) 2015 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
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the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Administrative Tag . . . . . . . . . . . . . . . . . . . . . 3 2. Administrative Tag . . . . . . . . . . . . . . . . . . . . . 3
3. TLV format . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. TLV format . . . . . . . . . . . . . . . . . . . . . . . . . 4
3.1. Per-node Admin Tag sub-TLV . . . . . . . . . . . . . . . 4 3.1. Per-node Admin Tag sub-TLV . . . . . . . . . . . . . . . 4
4. Elements of Procedure . . . . . . . . . . . . . . . . . . . . 5 4. Elements of Procedure . . . . . . . . . . . . . . . . . . . . 5
5. Applications . . . . . . . . . . . . . . . . . . . . . . . . 7 5. Applications . . . . . . . . . . . . . . . . . . . . . . . . 6
6. Security Considerations . . . . . . . . . . . . . . . . . . . 11 6. Security Considerations . . . . . . . . . . . . . . . . . . . 11
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12
8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 12 8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 12
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 12 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 12
9.1. Normative References . . . . . . . . . . . . . . . . . . 12 9.1. Normative References . . . . . . . . . . . . . . . . . . 12
9.2. Informative References . . . . . . . . . . . . . . . . . 12 9.2. Informative References . . . . . . . . . . . . . . . . . 12
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 13 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 13
1. Introduction 1. Introduction
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An administrative Tag is a 32-bit integer value that can be used to An administrative Tag is a 32-bit integer value that can be used to
identify a group of nodes in the IS-IS domain. The new sub-TLV identify a group of nodes in the IS-IS domain. The new sub-TLV
specifies one or more administrative tag values. An IS-IS router specifies one or more administrative tag values. An IS-IS router
advertises the set of groups it is part of in the specific IS-IS advertises the set of groups it is part of in the specific IS-IS
level. As an example, all PE-nodes may be configured with certain level. As an example, all PE-nodes may be configured with certain
tag value, whereas all P-nodes are configured with a different tag tag value, whereas all P-nodes are configured with a different tag
value. value.
The new sub-TLV defined will be carried inside the IS-IS Router The new sub-TLV defined will be carried inside the IS-IS Router
Capability TLV-242 [RFC4971]) in the Link State PDUs originated by Capability TLV-242 [RFC4971]) in the Link State PDUs originated by
the router. Link State PDUs [ISO10589] can be either flooded within the router. TLV 242 can be either specified to be flooded within the
the specific level (i.e. L1 or L2) or can be relayed across from one specific level in which the same has been originated, or they can be
level to another. Per-node administrative tags included in a TLV 242 specfied to be relayed from originating level to the other as well.
to be distributed within the specific level are perceived to have Per-node administrative tags that are included in a 'level-specific'
'level-wide' scope only. On the other hand, per-node administrative TLV 242 have a 'level-wide' flooding scope associated. On the other
tag included in a TLV 242 to be distributed across levels are hand, per-node administrative tags included in a 'domain-wide' TLV
perceived to have 'domain-wide' scope. 242 have 'domain-wide' flooding scope associated. For details on how
TLV 242 are flooded and relayed in the entire network please, refer
to [RFC4971].
Choosing the flooding scope to be associate with group tags are Choosing the flooding scope to be associated with group tags, is
defined by the needs of the operator's usage and is a matter of local defined by the needs of the operator's usage and is a matter of local
policy or configuration. Operator may choose to advertise a set of policy or configuration. Operator may choose to advertise a set of
per-node administrative tags across levels and another set of per- per-node administrative tags across levels and another set of per-
node administrative tags within the specific level. But evidently node administrative tags within the specific level. But evidently
the same set of per-node administrative tags cannot be advertised the same set of per-node administrative tags cannot be advertised
both across levels and within a specific level. A receiving IS-IS both across levels and within a specific level. A receiving IS-IS
router will not be able to distinguish between the significance of a router will not be able to distinguish between the significance of a
per-node administrative tag advertised globally from that of an per-node administrative tag advertised with 'domain-wide' scope, from
administrative tag advertised locally if they have the same value that of an administrative tag advertised with 'level-wide' scope, if
associated but different significance across different scopes. they have the same value associated but different significance across
different scopes.
Implementations SHOULD allow configuring one or more per-node Implementations SHOULD allow configuring one or more per-node
administrative tags to be advertised from a given device along with administrative tags to be advertised from a given device along with
the floofing scope associated with the same. It SHOULD allow the flooding scope associated with the same. It SHOULD allow
provisioning a set of per-node administrative tags having a 'domain- provisioning a set of per-node administrative tags having a 'domain-
wide' flooding scope, as well as, a set of per-node administrative wide' flooding scope, as well as, a set of per-node administrative
tags with 'level-wide' flooding scope only. A given per-node tags with 'level-wide' flooding scope only. A given per-node
administrative tag MAY be advertised with level-specific scope administrative tag MAY be advertised with level-specific scope
(Level-1 and/or Level-2) or with domain-wide scope, but MUST NOT be (Level-1 and/or Level-2) or with domain-wide scope, but MUST NOT be
advertised in both scopes. Hence implementations MUST NOT allow advertised in both scopes. Hence implementations MUST NOT allow
configuring the same per-node administrative tag values in both configuring the same per-node administrative tag values in both
'domain-wide' and 'level-wide' scopes. However the same 'domain-wide' and 'level-wide' scopes. However the same
administrative tag value MAY be allowed under multiple levels with administrative tag value MAY be allowed under multiple levels with
'level-wide' scope. 'level-wide' scope.
In deployments using multi-topology routing [RFC5120], since multiple The format of per-node Administrative Tag sub-TLV (see Section 3.1)
topologies within same IS-IS level do not use seprate Router does not include a topology identifier. Therefore it is not possible
Capability TLVs (i.e. they share the same flooding scope) a given to indicate a topology specific context when advertising per-node
per-node administrative tag cannot be associated with different admin tags. Hence, in deployments using multi-topology routing
charateristic or attribute under different topology. [RFC5120], advertising a separate set of per-node administrative tags
Implementations, in addition to letting user configuring a set of for each topology SHOULD NOT be supported.
'level-wide' and 'domain-wide' per-node administrative tags for each
level, MAY also allow configuring a set of 'level-wide' and 'domain-
wide' tags for each topology. Operators may like to associate a
single per-node administrative tag with same attribute across all
topologies under a specific (or all) levels. The same should be
provisioned under specific 'level-wide' (or 'domain-wide')
configurations. However advertising the same tag value across
multiple topologies will lead to same inconsistencies as with the
case of advertising same tag value across 'domain-wide' and 'level-
wide' flooding scope. Hence such implementations that allow
configuring topology-specific per-node administrative tags, MUST NOT
allow configuring the same topology-specific per-node administrative
tag across different topologies. They MUST only allow disjoint sets
of topology-specific 'level-wide' and 'domain-wide' per-node
administrative tags across different topologies.
3. TLV format 3. TLV format
3.1. Per-node Admin Tag sub-TLV 3.1. Per-node Admin Tag sub-TLV
The new Per-node Administrative Tag sub-TLV, like other ISIS The new Per-node Administrative Tag sub-TLV, like other ISIS
Capability sub-TLVs, is formatted as Type/Length/Value (TLV)triplets. Capability sub-TLVs, is formatted as Type/Length/Value (TLV)triplets.
Figure 1 below shows the format of the new sub-TLV. Figure 1 below shows the format of the new sub-TLV.
0 1 2 3 0 1 2 3
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dependent on the number of tags advertised. dependent on the number of tags advertised.
Value: A sequence of multiple 4 octets defining the Value: A sequence of multiple 4 octets defining the
administrative tags. administrative tags.
Figure 1: IS-IS Per-node Administrative Tag sub-TLV Figure 1: IS-IS Per-node Administrative Tag sub-TLV
The 'Per-node Admin Tag' sub-TLV may be generated more than once by The 'Per-node Admin Tag' sub-TLV may be generated more than once by
an originating router. This MAY happen if a node carries more than an originating router. This MAY happen if a node carries more than
63 per-node administrative groups and a single sub-TLV does not 63 per-node administrative groups and a single sub-TLV does not
provide sufficient space. As such occurence of the 'Per-node Admin provide sufficient space. As such occurrence of the 'Per-node Admin
Tag' sub-TLV does not cancel previous announcements, but rather is Tag' sub-TLV does not cancel previous announcements, but rather is
cumulative. cumulative.
4. Elements of Procedure 4. Elements of Procedure
Meaning of the Per-node administrative tags is generally opaque to Meaning of the Per-node administrative tags is generally opaque to
IS-IS. Router advertising the per-node administrative tag (or tags) IS-IS. Router advertising the per-node administrative tag (or tags)
may be configured to do so without knowing (or even explicitly may be configured to do so without knowing (or even explicitly
supporting) functionality implied by the tag. supporting) functionality implied by the tag.
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different scopes. Implementations MUST NOT allow configuring the different scopes. Implementations MUST NOT allow configuring the
same tag value across domain-wide and 'level-wide' scopes. The same same tag value across domain-wide and 'level-wide' scopes. The same
tag value MAY be allowed to be configured and advertised under tag value MAY be allowed to be configured and advertised under
'level-wide' scope for all levels. A IS-IS Area Border Router (ABR) 'level-wide' scope for all levels. A IS-IS Area Border Router (ABR)
participating in both levels 1 and 2 MAY advertise the same tag value participating in both levels 1 and 2 MAY advertise the same tag value
in the level-specific Router Capability TLVs with 'level-wide' scope in the level-specific Router Capability TLVs with 'level-wide' scope
generated by it. But the same tag value MUST not be advertised in generated by it. But the same tag value MUST not be advertised in
any of level 1 or level 2 Router-Capability TLV with 'domain-wide' any of level 1 or level 2 Router-Capability TLV with 'domain-wide'
flooding scope (refer to [RFC4971] for more details). flooding scope (refer to [RFC4971] for more details).
The per-node administrative tags sub-TLV don't need to be extended to
advertise newer per-node attributes or capabilities in future.
Future IS-IS protocol extensions MUST NOT require use of per-node Future IS-IS protocol extensions MUST NOT require use of per-node
administrative tags or define well-known tag values to advertise administrative tags or define well-known tag values to advertise
well-known capabilities. Per-node administrative tags are for well-known capabilities. Per-node administrative tags are for
generic use and do not require IANA registry. Theny future IS-IS generic use and do not require IANA registry.
extensions requiring well known values to advertise well-known
capabilities MAY define and use new Router Capability sub-TLVs
tailored to the needs of the specific solution (refer to [RFC4971]
for more details).
Being part of the Router Capability TLV, the per-node administrative Being part of the Router Capability TLV, the per-node administrative
tag sub-TLV MUST be reasonably small and stable. In particular, but tag sub-TLV MUST be reasonably small and stable. In particular, but
not limited to, implementations supporting the per-node not limited to, implementations supporting the per-node
administrative tags MUST NOT associate advertised tags to changes in administrative tags MUST NOT associate advertised tags to changes in
the network topology (both within and outside the IS-IS domain) or the network topology (both within and outside the IS-IS domain) or
reachability of routes. reachability of routes.
5. Applications 5. Applications
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7. IANA Considerations 7. IANA Considerations
IANA maintains the registry for the Router Capability sub-TLVs. IS- IANA maintains the registry for the Router Capability sub-TLVs. IS-
IS Administrative Tags will require new type code for the following IS Administrative Tags will require new type code for the following
new sub-TLV defined in this document. new sub-TLV defined in this document.
i) Per-Node-Admin-Tag Sub-TLV, Type: TBD i) Per-Node-Admin-Tag Sub-TLV, Type: TBD
8. Acknowledgments 8. Acknowledgments
Many thanks to Les Ginsberg, Dhruv Dhody, Uma Chunduri for useful Many thanks to Les Ginsberg, Dhruv Dhody, Uma Chunduri and Chris
inputs. Thanks to Chris Bowers for providing useful inputs to remove Bowers for providing useful inputs.
ambiguity related to tag-ordering.
9. References 9. References
9.1. Normative References 9.1. Normative References
[ISO10589] [ISO10589]
"Intermediate system to Intermediate system intra-domain "Intermediate system to Intermediate system intra-domain
routeing information exchange protocol for use in routeing information exchange protocol for use in
conjunction with the protocol for providing the conjunction with the protocol for providing the
connectionless-mode Network Service (ISO 8473), ISO/IEC connectionless-mode Network Service (ISO 8473), ISO/IEC
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