Internet DRAFT - draft-ietf-lsr-ospf-admin-tags
draft-ietf-lsr-ospf-admin-tags
Network Working Group A. Lindem, Ed.
Internet-Draft LabN Consulting, L.L.C.
Intended status: Standards Track P. Psenak
Expires: 5 September 2024 Cisco Systems
Y. Qu
Futurewei Technologies
4 March 2024
Extensions to OSPF for Advertising Prefix Administrative Tags
draft-ietf-lsr-ospf-admin-tags-16
Abstract
It is useful for routers in OSPFv2 and OSPFv3 routing domains to be
able to associate tags with prefixes. Previously, OSPFv2 and OSPFv3
were relegated to a single tag and only for AS External and Not-So-
Stubby-Area (NSSA) prefixes. With the flexible encodings provided by
OSPFv2 Prefix/Link Attribute Advertisement and OSPFv3 Extended LSAs,
multiple administrative tags may be advertised for all types of
prefixes. These administrative tags can be used for many
applications including route redistribution policy, selective prefix
prioritization, selective IP Fast-ReRoute (IPFRR) prefix protection,
and many others.
The ISIS protocol supports a similar mechanism that is described in
RFC 5130.
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 https://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 5 September 2024.
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Copyright Notice
Copyright (c) 2024 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 (https://trustee.ietf.org/
license-info) in effect on the date of publication of this document.
Please review these documents carefully, as they describe your rights
and restrictions with respect to this document. Code Components
extracted from this document must include Revised BSD License text as
described in Section 4.e of the Trust Legal Provisions and are
provided without warranty as described in the Revised BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3
2. 32-Bit Administrative Tag Sub-TLV . . . . . . . . . . . . . . 3
3. Administrative Tag Applicability . . . . . . . . . . . . . . 4
4. Protocol Operation . . . . . . . . . . . . . . . . . . . . . 5
4.1. Equal-Cost Multipath Applicability . . . . . . . . . . . 6
5. BGP-LS Advertisement . . . . . . . . . . . . . . . . . . . . 6
6. Management Considerations . . . . . . . . . . . . . . . . . . 6
7. YANG Data Model . . . . . . . . . . . . . . . . . . . . . . . 6
8. Security Considerations . . . . . . . . . . . . . . . . . . . 15
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 16
10. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 16
11. Normative References . . . . . . . . . . . . . . . . . . . . 16
12. Informative References . . . . . . . . . . . . . . . . . . . 18
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 19
1. Introduction
It is useful for routers in OSPFv2 [RFC2328] and OSPFv3 [RFC5340]
routing domains to be able to associate tags with prefixes.
Previously, OSPFv2 and OSPFv3 were relegated to a single tag and only
for AS External and Not-So-Stubby-Area (NSSA) prefixes. With the
flexible encodings provided by OSPFv2 Prefix/Link Attribute
Advertisement ([RFC7684]) and OSPFv3 Extended LSA ([RFC8362]),
multiple administrative tags may be advertised for all types of
prefixes. These administrative tags can be used in many applications
including (but not limited to):
1. Controlling which routes are redistributed into other protocols
for re-advertisement.
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2. Prioritizing selected prefixes for faster convergence and
installation in the forwarding plane.
3. Identifying selected prefixes for Loop-Free Alternative (LFA)
protection.
Throughout this document, OSPF is used when the text applies to both
OSPFv2 and OSPFv3. OSPFv2 or OSPFv3 is used when the text is
specific to one version of the OSPF protocol.
The definition of the 64-bit tag was considered but discard given
that there is no strong requirement or use case. The specification
is included here for information.
The ISIS protocol supports a similar mechanism that is described in
RFC 5130 [RFC5130].
1.1. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
2. 32-Bit Administrative Tag Sub-TLV
This document creates a new Administrative Tag Sub-TLV for OSPFv2 and
OSPFv3. This Sub-TLV specifies one or more 32-bit unsigned integers
that may be associated with an OSPF advertised prefix. The precise
usage of these tags is beyond the scope of this document.
The format of the 32-bit Administrative Tag TLV is as follows:
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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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| First 32-bit Administrative Tag |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| o |
o
| o |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Last 32-bit Administrative Tag |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type A 16-bit field set to TBD.
Length A 16-bit field that indicates the length of the value
portion in octets and MUST be a multiple of 4 octets
dependent on the number of administrative tags
advertised. At least one administrative tag must be
advertised.
Value A variable length list of one or more administrative
tags.
Figure 1: 32-bit Administrative Tag Sub-TLV
This sub-TLV will carry one or more 32-bit unsigned integer values
that will be used as administrative tags. If the length is 0 or not
a multiple of 4 octets, the sub-TLV MUST be ignored and the reception
SHOULD be logged for further analysis (subject to rate-limiting).
3. Administrative Tag Applicability
The administrative tag TLV specified herein will be valid as a sub-
TLV of the following TLVs specified in [RFC7684]:
1. Extended Prefix TLV advertised in the OSPFv2 Extended Prefix LSA
The administrative tag TLV specified herein will be valid as a sub-
TLV of the following TLVs specified in [RFC8362]:
1. Inter-Area-Prefix TLV advertised in the E-Inter-Area-Prefix-LSA
2. Intra-Area-Prefix TLV advertised in the E-Intra-Area-Prefix-LSA.
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3. External-Prefix TLV advertised in the E-AS-External-LSA and the
E-NSSA-LSA
4. Protocol Operation
An OSPF router supporting this specification MUST be able to
advertise and interpret at least one 32-bit tag for all type of
prefixes. An OSPF router supporting this specification MAY be able
to advertise and propagate multiple 32-bit tags. The maximum tags
that an implementation supports is a local matter depending upon
supported applications using prefix tags.
When tags are advertised for AS External or NSSA LSA prefixes, the
existing tag in the OSPFv2 and OSPFv3 AS-External-LSA and NSSA-LSA
encodings SHOULD be utilized for the first tag. This will facilitate
backward compatibility with implementations that do not support this
specification.
An OSPF router supporting this specification SHOULD propagate
administrative tags when acting as an Area Border Router and
originating summary advertisements into other areas (unless inhibited
by local policy Section 6). Similarly, an OSPF router supporting
this specification and acting as an ABR for a Not-So-Stubby Area
(NSSA) SHOULD propagate tags when translating NSSA routes to AS
External advertisements [RFC3101] (also subject to local policy
Section 6).
The semantics of the tag order are implementation-dependent. That
is, there is no implied meaning to the ordering of the tags that
indicates a certain operation or set of operations need be performed
based on the order of the tags. Each tag SHOULD be treated as an
autonomous identifier that MAY be used in policy to perform a policy
action. Whether or not tag A precedes or succeeds tag B SHOULD not
change the meaning of the tag set. The number of tags supported MAY
limit the number of tags that are propagated. When propagating
multiple tags between areas as previously described, the order of the
the tags SHOULD be preserved so that implementations supporting fewer
tags will have a consistent view across areas.
For configured area ranges, NSSA ranges, and configured aggregation
of redistributed routes, tags from component routes SHOULD NOT be
propagated to the summary. Implementations SHOULD provide a
mechanism to configure multiple tags for area ranges, NSSA ranges,
and redistributed route summaries.
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4.1. Equal-Cost Multipath Applicability
When multiple LSAs contribute to an OSPF route, it is possible that
these LSAs will all have different tags. In this situation, the OSPF
router MUST associate the tags from one of the LSAs contributing a
path and, if the implementation supports multiple tags, MAY associate
tags from multiple contributing LSAs up to the maximum number of tags
supported. It is RECOMMENDED that tags from LSAs are added to the
path in ascending order of LSA originator Router-ID.
5. BGP-LS Advertisement
BGP-LS [RFC9552] introduced the support for advertising
administrative tags associated with prefixes using the BGP-LS IGP
Route Tag TLV (TLV 1153) that is used to carry the OSPF
Administrative Tags specified in this document.
6. Management Considerations
Implementations MAY include configuration of policies to inhibit the
advertisement of tags on and redistributed prefixes. Implementations
MAY also include configuration of policies to filter the propagation
of admin-tags between areas (OSPFv2 Extended Prefix LSAs, OSPFv3 E-
Inter-Area-Prefix-LSAs, and translated OSPFv3 E-AS-External-LSAs).
However, the default behavior SHOULD be to advertise or propagate the
lesser number of all the tags associated with the prefix or the
maximum number of tags supported by the implementation.
7. YANG Data Model
YANG [RFC7950] is a data definition language used to define the
contents of a conceptual data store that allows networked devices to
be managed using NETCONF [RFC6241] or RESTCONF [RFC8040].
This section defines a YANG data model that can be used to configure
and manage the prefix administrative tags defined in this document,
which augments the OSPF YANG data model [RFC9129] and the OSPFv3
Extended LSA YANG data model [I-D.ietf-lsr-ospfv3-extended-lsa-yang].
The following show the tree diagram of the module:
module: ietf-ospf-admin-tags
augment /rt:routing/rt:control-plane-protocols
/rt:control-plane-protocol/ospf:ospf/ospf:areas/ospf:area
/ospf:ranges/ospf:range:
+--rw admin-tags
+--rw tags* uint32
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augment /rt:routing/rt:control-plane-protocols
/rt:control-plane-protocol/ospf:ospf/ospf:areas/ospf:area
/ospf:interfaces/ospf:interface:
+--rw admin-tags
+--rw tags* [tag]
+--rw tag uint32
+--rw advertise-prefixes* [prefix]
+--rw prefix inet:ip-prefix
augment /rt:routing/rt:control-plane-protocols
/rt:control-plane-protocol/ospf:ospf/ospf:areas/ospf:area
/ospf:interfaces/ospf:interface/ospf:database
/ospf:link-scope-lsa-type/ospf:link-scope-lsas
/ospf:link-scope-lsa/ospf:version/ospf:ospfv2/ospf:ospfv2
/ospf:body/ospf:opaque/ospf:extended-prefix-opaque
/ospf:extended-prefix-tlv:
+--ro perfix-admin-tag-sub-tlvs
+--ro admin-tag-sub-tlv* []
+--ro admin-tags* uint32
augment /rt:routing/rt:control-plane-protocols
/rt:control-plane-protocol/ospf:ospf/ospf:areas/ospf:area
/ospf:database/ospf:area-scope-lsa-type/ospf:area-scope-lsas
/ospf:area-scope-lsa/ospf:version/ospf:ospfv2/ospf:ospfv2
/ospf:body/ospf:opaque/ospf:extended-prefix-opaque
/ospf:extended-prefix-tlv:
+--ro perfix-admin-tag-sub-tlvs
+--ro admin-tag-sub-tlv* []
+--ro admin-tags* uint32
vv augment /rt:routing/rt:control-plane-protocols
/rt:control-plane-protocol/ospf:ospf/ospf:database
/ospf:as-scope-lsa-type/ospf:as-scope-lsas/ospf:as-scope-lsa
/ospf:version/ospf:ospfv2/ospf:ospfv2/ospf:body/ospf:opaque
/ospf:extended-prefix-opaque/ospf:extended-prefix-tlv:
+--ro perfix-admin-tag-sub-tlvs
+--ro admin-tag-sub-tlv* []
+--ro admin-tags* uint32
augment /rt:routing/rt:control-plane-protocols
/rt:control-plane-protocol/ospf:ospf/ospf:areas/ospf:area
/ospf:database/ospf:area-scope-lsa-type/ospf:area-scope-lsas
/ospf:area-scope-lsa/ospf:version/ospf:ospfv3/ospf:ospfv3
/ospf:body/ospfv3-e-lsa:e-inter-area-prefix
/ospfv3-e-lsa:e-inter-prefix-tlvs
/ospfv3-e-lsa:inter-prefix-tlv:
+--ro perfix-admin-tag-sub-tlvs
+--ro admin-tag-sub-tlv* []
+--ro admin-tags* uint32
augment /rt:routing/rt:control-plane-protocols
/rt:control-plane-protocol/ospf:ospf/ospf:areas/ospf:area
/ospf:database/ospf:area-scope-lsa-type/ospf:area-scope-lsas
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/ospf:area-scope-lsa/ospf:version/ospf:ospfv3/ospf:ospfv3
/ospf:body/ospfv3-e-lsa:e-intra-area-prefix
/ospfv3-e-lsa:e-intra-prefix-tlvs
/ospfv3-e-lsa:intra-prefix-tlv:
+--ro perfix-admin-tag-sub-tlvs
+--ro admin-tag-sub-tlv* []
+--ro admin-tags* uint32
augment /rt:routing/rt:control-plane-protocols
/rt:control-plane-protocol/ospf:ospf/ospf:database
/ospf:as-scope-lsa-type/ospf:as-scope-lsas/ospf:as-scope-lsa
/ospf:version/ospf:ospfv3/ospf:ospfv3/ospf:body
/ospfv3-e-lsa:e-as-external/ospfv3-e-lsa:e-external-tlvs
/ospfv3-e-lsa:external-prefix-tlv:
+--ro perfix-admin-tag-sub-tlvs
+--ro admin-tag-sub-tlv* []
+--ro admin-tags* uint32
augment /rt:routing/rt:control-plane-protocols
/rt:control-plane-protocol/ospf:ospf/ospf:areas/ospf:area
/ospf:database/ospf:area-scope-lsa-type/ospf:area-scope-lsas
/ospf:area-scope-lsa/ospf:version/ospf:ospfv3/ospf:ospfv3
/ospf:body/ospfv3-e-lsa:e-nssa/ospfv3-e-lsa:e-external-tlvs
/ospfv3-e-lsa:external-prefix-tlv:
+--ro perfix-admin-tag-sub-tlvs
+--ro admin-tag-sub-tlv* []
+--ro admin-tags* uint32
The following is the YANG module:
<CODE BEGINS> file "ietf-ospf-admin-tags@2024-01-04.yang"
module ietf-ospf-admin-tags {
yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-ospf-admin-tags";
prefix ospf-admin-tags;
import ietf-routing {
prefix rt;
reference
"RFC 8349: A YANG Data Model for Routing
Management (NMDA Version)";
}
import ietf-ospf {
prefix ospf;
reference
"RFC 9129: YANG Data Model for the OSPF Protocol.";
}
import ietf-inet-types {
prefix inet;
reference
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"RFC 6991: Common YANG Data Types";
}
import ietf-ospfv3-extended-lsa {
prefix ospfv3-e-lsa;
reference
"RFC xxxx: YANG Model for OSPFv3 Extended LSAs.";
}
organization
"IETF LSR - Link State Routing Working Group";
contact
"WG Web: <https://datatracker.ietf.org/wg/lsr/>
WG List: <mailto:lsr@ietf.org>
Author: Yingzhen Qu
<mailto:yingzhen.ietf@gmail.com>
Author: Acee Lindem
<mailto:acee.ietf@gmail.com>
Author: Peter Psenak
<mailto:ppsenak@cisco.com>";
description
"This YANG module defines the configuration
and operational state for OSPF administrative tags.
This YANG model conforms to the Network Management
Datastore Architecture (NMDA) as described in RFC 8342.
Copyright (c) 2024 IETF Trust and the persons identified as
authors of the code. All rights reserved.
Redistribution and use in source and binary forms, with or
without modification, is permitted pursuant to, and subject to
the license terms contained in, the Revised BSD License set
forth in Section 4.c of the IETF Trust's Legal Provisions
Relating to IETF Documents
(https://trustee.ietf.org/license-info).
This version of this YANG module is part of RFC XXXX;
see the RFC itself for full legal notices.
The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL
NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'NOT RECOMMENDED',
'MAY', and 'OPTIONAL' in this document are to be interpreted as
described in BCP 14 (RFC 2119) (RFC 8174) when, and only when,
they appear in all capitals, as shown here.";
reference
"RFC XXXX";
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revision 2024-01-04 {
description
"Initial revision.";
reference
"RFC XXXX: YANG Data Model for OSPF Prefix Administrative
Tags.";
}
grouping prefix-admin-tag-sub-tlvs {
description
"Prefix Administrative Tag sub-TLVs.";
container perfix-admin-tag-sub-tlvs {
config false;
description
"Prefix admin tag sub-TLV.";
list admin-tag-sub-tlv {
description
"Prefix admin tag sub-TLV.";
leaf-list admin-tags {
type uint32;
description
"32-bit administrative tag.";
}
}
}
}
/* Configuration */
augment "/rt:routing/rt:control-plane-protocols/"
+ "rt:control-plane-protocol/ospf:ospf/"
+ "ospf:areas/ospf:area/ospf:ranges/ospf:range" {
when "derived-from-or-self(../../../../../"
+ "rt:type, 'ospf:ospf')" {
description
"This augments the OSPF routing protocol area range
configuration.";
}
description
"This augments the OSPF protocol area range configuration
with Administrative Tags. The configured tags will be
advertised with summary prefix when it is active.";
container admin-tags {
when "../ospf:advertise = 'true'";
leaf-list tags {
type uint32;
description
"32-bit administrative tags.";
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}
description
"OSPF prefix administrative tags.";
}
}
augment "/rt:routing/rt:control-plane-protocols/"
+ "rt:control-plane-protocol/ospf:ospf/"
+ "ospf:areas/ospf:area/ospf:interfaces/ospf:interface" {
when "derived-from-or-self(../../../../../"
+ "rt:type, 'ospf:ospf')" {
description
"This augments the OSPF routing protocol interface
configuration.";
}
description
"This augments the OSPF protocol interface configuration
with Administrative Tags. The configured tags will be
advertised with local prefixes configured for the interface.";
container admin-tags {
list tags {
key "tag";
leaf tag {
type uint32;
description
"32-bit administrative tag.";
}
list advertise-prefixes {
key "prefix";
leaf prefix {
type inet:ip-prefix;
description
"IPv4 or IPv6 prefix";
}
description
"By default, the tag advertised will be advertised
for all prefixes associated with the interface.
If advertise-prefixes is specified, the tag is
only applied to interfaces prefixes in the list";
}
description
"List of administrative tags that are to be advertised
with prefixes associated with the interfaces. Optionally,
tag advertisement may be restricted to specific
prefixes.";
}
description
"OSPF prefix administrative tags.";
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}
}
/* Database */
augment "/rt:routing/"
+ "rt:control-plane-protocols/rt:control-plane-protocol/"
+ "ospf:ospf/ospf:areas/ospf:area/"
+ "ospf:interfaces/ospf:interface/ospf:database/"
+ "ospf:link-scope-lsa-type/ospf:link-scope-lsas/"
+ "ospf:link-scope-lsa/ospf:version/ospf:ospfv2/"
+ "ospf:ospfv2/ospf:body/ospf:opaque/"
+ "ospf:extended-prefix-opaque/ospf:extended-prefix-tlv" {
when "derived-from-or-self(../../../../../../../../../../"
+ "../../../../rt:type, 'ospf:ospfv2')" {
description
"This augmentation is only valid for OSPFv2.";
}
description
"Prefix Administrative Tag Sub-TLVs for OSPFv2 extended prefix
TLV in type 9 opaque LSA.";
uses prefix-admin-tag-sub-tlvs;
}
augment "/rt:routing/"
+ "rt:control-plane-protocols/rt:control-plane-protocol/"
+ "ospf:ospf/ospf:areas/"
+ "ospf:area/ospf:database/"
+ "ospf:area-scope-lsa-type/ospf:area-scope-lsas/"
+ "ospf:area-scope-lsa/ospf:version/ospf:ospfv2/"
+ "ospf:ospfv2/ospf:body/ospf:opaque/"
+ "ospf:extended-prefix-opaque/ospf:extended-prefix-tlv" {
when "derived-from-or-self(../../../../../../../../../../"
+ "../../rt:type, 'ospf:ospfv2')" {
description
"This augmentation is only valid for OSPFv2.";
}
description
"Prefix Administrative Tag Sub-TLVs for OSPFv2 extended prefix
TLV in type 10 opaque LSA.";
uses prefix-admin-tag-sub-tlvs;
}
augment "/rt:routing/"
+ "rt:control-plane-protocols/rt:control-plane-protocol/"
+ "ospf:ospf/ospf:database/"
+ "ospf:as-scope-lsa-type/ospf:as-scope-lsas/"
+ "ospf:as-scope-lsa/ospf:version/ospf:ospfv2/"
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+ "ospf:ospfv2/ospf:body/ospf:opaque/"
+ "ospf:extended-prefix-opaque/ospf:extended-prefix-tlv" {
when "derived-from-or-self(../../../../../../../../"
+ "../../rt:type, 'ospf:ospfv2')" {
description
"This augmentation is only valid for OSPFv2.";
}
description
"Prefix Administrative Tag Sub-TLVs for OSPFv2 extended prefix
TLV in type 11 opaque LSA.";
uses prefix-admin-tag-sub-tlvs;
}
augment "/rt:routing/"
+ "rt:control-plane-protocols/rt:control-plane-protocol/"
+ "ospf:ospf/ospf:areas/ospf:area/ospf:database/"
+ "ospf:area-scope-lsa-type/ospf:area-scope-lsas/"
+ "ospf:area-scope-lsa/ospf:version/ospf:ospfv3/"
+ "ospf:ospfv3/ospf:body/ospfv3-e-lsa:e-inter-area-prefix/"
+ "ospfv3-e-lsa:e-inter-prefix-tlvs/"
+ "ospfv3-e-lsa:inter-prefix-tlv" {
when "derived-from-or-self(../../../../../../../../../../"
+ "../../rt:type, 'ospf:ospfv3')" {
description
"This augmentation is only valid for OSPFv3.";
}
description
"Augment OSPFv3 Inter-Area-Prefix TLV in the
E-Inter-Area-Prefix LSA.";
uses prefix-admin-tag-sub-tlvs;
}
augment "/rt:routing/"
+ "rt:control-plane-protocols/rt:control-plane-protocol/"
+ "ospf:ospf/ospf:areas/ospf:area/ospf:database/"
+ "ospf:area-scope-lsa-type/ospf:area-scope-lsas/"
+ "ospf:area-scope-lsa/ospf:version/ospf:ospfv3/"
+ "ospf:ospfv3/ospf:body/ospfv3-e-lsa:e-intra-area-prefix/"
+ "ospfv3-e-lsa:e-intra-prefix-tlvs/"
+ "ospfv3-e-lsa:intra-prefix-tlv" {
when "/rt:routing/rt:control-plane-protocols"
+ "/rt:control-plane-protocol/rt:type = 'ospf:ospfv3'" {
description
"This augmentation is only valid for OSPFv3.";
}
description
"Augment OSPFv3 Intra-Area-Prefix TLV in the
E-Intra-Area-Prefix LSA.";
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uses prefix-admin-tag-sub-tlvs;
}
augment "/rt:routing/"
+ "rt:control-plane-protocols/rt:control-plane-protocol/"
+ "ospf:ospf/ospf:database/"
+ "ospf:as-scope-lsa-type/ospf:as-scope-lsas/"
+ "ospf:as-scope-lsa/ospf:version/ospf:ospfv3/"
+ "ospf:ospfv3/ospf:body/ospfv3-e-lsa:e-as-external/"
+ "ospfv3-e-lsa:e-external-tlvs/"
+ "ospfv3-e-lsa:external-prefix-tlv" {
when "derived-from-or-self(../../../../../../../../"
+ "../../rt:type, 'ospf:ospfv3')" {
description
"This augmentation is only valid for OSPFv3.";
}
description
"Augment OSPFv3 External-Prefix TLV in the E-AS-External-LSA.";
uses prefix-admin-tag-sub-tlvs;
}
augment "/rt:routing/"
+ "rt:control-plane-protocols/rt:control-plane-protocol/"
+ "ospf:ospf/ospf:areas/ospf:area/ospf:database/"
+ "ospf:area-scope-lsa-type/ospf:area-scope-lsas/"
+ "ospf:area-scope-lsa/ospf:version/ospf:ospfv3/"
+ "ospf:ospfv3/ospf:body/ospfv3-e-lsa:e-nssa/"
+ "ospfv3-e-lsa:e-external-tlvs/"
+ "ospfv3-e-lsa:external-prefix-tlv" {
when "/rt:routing/rt:control-plane-protocols"
+ "/rt:control-plane-protocol/rt:type = 'ospf:ospfv3'" {
description
"This augmentation is only valid for OSPFv3.";
}
description
"Augment OSPFv3 External-Prefix TLV in the E-NSSA-LSA.";
uses prefix-admin-tag-sub-tlvs;
}
}
<CODE ENDS>
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8. Security Considerations
This document describes a generic mechanism for advertising
administrative tags for OSPF prefixes. The administrative tags are
generally less critical than the topology information currently
advertised by the base OSPF protocol. The security considerations
for the generic mechanism are dependent on their application. One
such application is to control leaking of OSPF routes to other
protocols (e.g., BGP [RFC4271]). If an attacker were able to modify
the admin tags associated with OSPF routes and they were being used
for this application, such routes could be prevented from being
advertised in routing domains where they are required (subtle denial
or service) or they could be advertised into routing domains where
they shouldn't be advertised (routing vulnerability). Security
considerations for the base OSPF protocol are covered in [RFC2328]
and [RFC5340].
The YANG modules specified in this document define a schema for data
that is designed to be accessed via network management protocols such
as NETCONF [RFC6241] or RESTCONF [RFC8040]. The lowest NETCONF layer
is the secure transport layer, and the mandatory-to-implement secure
transport is Secure Shell (SSH) [RFC6242]. The lowest RESTCONF layer
is HTTPS, and the mandatory-to-implement secure transport is TLS
[RFC8446].
The NETCONF Access Control Model (NACM) [RFC8341] provides the means
to restrict access for particular NETCONF or RESTCONF users to a pre-
configured subset of all available NETCONF or RESTCONF protocol
operations and content.
The following data nodes defined in the YANG module that are
writable/creatable/deletable (i.e., config true, which is the
default). The modifications to these data nodes without proper
protection can have a negative effect on network operations.
/ospf:ospf/ospf:areas/ospf:area/ospf:interfaces/ospf:interface/
admin-tags
/ospf:ospf/ospf:areas/ospf:area/ospf:ranges/ospf:range/admin-tags
Some of the readable data nodes in this YANG module may be considered
sensitive or vulnerable in some network environments. Exposure of
the OSPF link state database may be useful in mounting a Denial-of-
Service (DoS) attacks. These are the readable data nodes:
/ospf:ospf/ospf:areas/ospf:area/ospf:interfaces/ospf:interface/
admin-tags
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/ospf:ospf/ospf:areas/ospf:area/ospf:ranges/ospf:range/admin-tags
/prefix-admin-tag-sub-tlvs
9. IANA Considerations
The following values should be allocated from the OSPF Extended
Prefix TLV Sub-TLV Registry [RFC7684]:
* TBD - 32-bit Administrative Tag TLV
The following values should be allocated from the OSPFv3 Extended-LSA
Sub-TLV Registry [RFC8362]:
* TBD - 32-bit Administrative Tag TLV
The IANA is requested to assign one new URI from the IETF XML
registry ([RFC3688]). Authors are suggesting the following URI:
URI: urn:ietf:params:xml:ns:yang:ietf-ospf-admin-tags
Registrant Contact: The IESG.
XML: N/A, the requested URI is an XML namespace
This document also requests one new YANG module name in the YANG
Module Names registry ([RFC6020]) with the following suggestion :
name: ietf-ospf-admin-tags
namespace: urn:ietf:params:xml:ns:yang:ietf-ospf-admin-tags
prefix: ospf-admin-tags
reference: RFC XXXX
10. Acknowledgments
The authors of RFC 5130 [RFC5130] are acknowledged since this
document draws upon both the ISIS specification and deployment
experience. The text in Section 4 is adopted from RFC 5130.
Thanks to Donnie Savage for his comments and questions.
Thanks to Ketan Talaulikar for his comments and providing the BGP-LS
text.
Thanks to Tony Przygienda and Les Ginsberg for discussions on tag
selection.
11. Normative References
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[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC2328] Moy, J., "OSPF Version 2", STD 54, RFC 2328,
DOI 10.17487/RFC2328, April 1998,
<https://www.rfc-editor.org/info/rfc2328>.
[RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
DOI 10.17487/RFC3688, January 2004,
<https://www.rfc-editor.org/info/rfc3688>.
[RFC5340] Coltun, R., Ferguson, D., Moy, J., and A. Lindem, "OSPF
for IPv6", RFC 5340, DOI 10.17487/RFC5340, July 2008,
<https://www.rfc-editor.org/info/rfc5340>.
[RFC6020] Bjorklund, M., Ed., "YANG - A Data Modeling Language for
the Network Configuration Protocol (NETCONF)", RFC 6020,
DOI 10.17487/RFC6020, October 2010,
<https://www.rfc-editor.org/info/rfc6020>.
[RFC6241] Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed.,
and A. Bierman, Ed., "Network Configuration Protocol
(NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011,
<https://www.rfc-editor.org/info/rfc6241>.
[RFC6242] Wasserman, M., "Using the NETCONF Protocol over Secure
Shell (SSH)", RFC 6242, DOI 10.17487/RFC6242, June 2011,
<https://www.rfc-editor.org/info/rfc6242>.
[RFC7684] Psenak, P., Gredler, H., Shakir, R., Henderickx, W.,
Tantsura, J., and A. Lindem, "OSPFv2 Prefix/Link Attribute
Advertisement", RFC 7684, DOI 10.17487/RFC7684, November
2015, <https://www.rfc-editor.org/info/rfc7684>.
[RFC7950] Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language",
RFC 7950, DOI 10.17487/RFC7950, August 2016,
<https://www.rfc-editor.org/info/rfc7950>.
[RFC8040] Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF
Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017,
<https://www.rfc-editor.org/info/rfc8040>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
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[RFC8341] Bierman, A. and M. Bjorklund, "Network Configuration
Access Control Model", STD 91, RFC 8341,
DOI 10.17487/RFC8341, March 2018,
<https://www.rfc-editor.org/info/rfc8341>.
[RFC8362] Lindem, A., Roy, A., Goethals, D., Reddy Vallem, V., and
F. Baker, "OSPFv3 Link State Advertisement (LSA)
Extensibility", RFC 8362, DOI 10.17487/RFC8362, April
2018, <https://www.rfc-editor.org/info/rfc8362>.
[RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol
Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
<https://www.rfc-editor.org/info/rfc8446>.
[RFC9129] Yeung, D., Qu, Y., Zhang, Z., Chen, I., and A. Lindem,
"YANG Data Model for the OSPF Protocol", RFC 9129,
DOI 10.17487/RFC9129, October 2022,
<https://www.rfc-editor.org/info/rfc9129>.
[RFC9552] Talaulikar, K., Ed., "Distribution of Link-State and
Traffic Engineering Information Using BGP", RFC 9552,
DOI 10.17487/RFC9552, December 2023,
<https://www.rfc-editor.org/info/rfc9552>.
[I-D.ietf-lsr-ospfv3-extended-lsa-yang]
Lindem, A., Palani, S., and Y. Qu, "YANG Model for OSPFv3
Extended LSAs", Work in Progress, Internet-Draft, draft-
ietf-lsr-ospfv3-extended-lsa-yang-29, 2 February 2024,
<https://datatracker.ietf.org/doc/html/draft-ietf-lsr-
ospfv3-extended-lsa-yang-29>.
12. Informative References
[RFC3101] Murphy, P., "The OSPF Not-So-Stubby Area (NSSA) Option",
RFC 3101, DOI 10.17487/RFC3101, January 2003,
<https://www.rfc-editor.org/info/rfc3101>.
[RFC4271] Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A
Border Gateway Protocol 4 (BGP-4)", RFC 4271,
DOI 10.17487/RFC4271, January 2006,
<https://www.rfc-editor.org/info/rfc4271>.
[RFC5130] Previdi, S., Shand, M., Ed., and C. Martin, "A Policy
Control Mechanism in IS-IS Using Administrative Tags",
RFC 5130, DOI 10.17487/RFC5130, February 2008,
<https://www.rfc-editor.org/info/rfc5130>.
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Authors' Addresses
Acee Lindem (editor)
LabN Consulting, L.L.C.
301 Midenhall Way
Cary, NC 27513
United States of America
Email: acee.ietf@gmail.com
Peter Psenak
Cisco Systems
Apollo Business Center
Mlynske nivy 43
Bratislava 821 09
Slovakia
Email: ppsenak@cisco.com
Yingzhen Qu
Futurewei Technologies
2330 Central Expressway
Santa Clara, CA 95050
United States of America
Email: yingzhen.ietf@gmail.com
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