draft-ietf-isis-te-app-14.txt   draft-ietf-isis-te-app-15.txt 
Networking Working Group L. Ginsberg Networking Working Group L. Ginsberg
Internet-Draft P. Psenak Internet-Draft P. Psenak
Intended status: Standards Track Cisco Systems Intended status: Standards Track Cisco Systems
Expires: December 5, 2020 S. Previdi Expires: December 13, 2020 S. Previdi
Huawei Huawei
W. Henderickx W. Henderickx
Nokia Nokia
J. Drake J. Drake
Juniper Networks Juniper Networks
June 3, 2020 June 11, 2020
IS-IS TE Attributes per application IS-IS TE Attributes per application
draft-ietf-isis-te-app-14 draft-ietf-isis-te-app-15
Abstract Abstract
Existing traffic engineering related link attribute advertisements Existing traffic engineering related link attribute advertisements
have been defined and are used in RSVP-TE deployments. Since the have been defined and are used in RSVP-TE deployments. Since the
original RSVP-TE use case was defined, additional applications (e.g., original RSVP-TE use case was defined, additional applications (e.g.,
Segment Routing Traffic Engineering, Loop Free Alternate) have been Segment Routing Policy, Loop Free Alternate) that also make use of
defined which also make use of the link attribute advertisements. In the link attribute advertisements have been defined . In cases where
cases where multiple applications wish to make use of these link multiple applications wish to make use of these link attributes, the
attributes the current advertisements do not support application current advertisements do not support application specific values for
specific values for a given attribute nor do they support indication a given attribute, nor do they support indication of which
of which applications are using the advertised value for a given applications are using the advertised value for a given link. This
link. This document introduces new link attribute advertisements document introduces new link attribute advertisements that address
which address both of these shortcomings. both of these shortcomings.
Requirements Language Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP "OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here. capitals, as shown here.
Status of This Memo Status of This Memo
skipping to change at page 2, line 10 skipping to change at page 2, line 10
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 https://datatracker.ietf.org/drafts/current/. Drafts is at https://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 December 5, 2020. This Internet-Draft will expire on December 13, 2020.
Copyright Notice Copyright Notice
Copyright (c) 2020 IETF Trust and the persons identified as the Copyright (c) 2020 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
(https://trustee.ietf.org/license-info) in effect on the date of (https://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
carefully, as they describe your rights and restrictions with respect carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of include Simplified BSD License text as described in Section 4.e of
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 . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Requirements Discussion . . . . . . . . . . . . . . . . . . . 4 2. Requirements Discussion . . . . . . . . . . . . . . . . . . . 4
3. Legacy Advertisements . . . . . . . . . . . . . . . . . . . . 4 3. Legacy Advertisements . . . . . . . . . . . . . . . . . . . . 5
3.1. Legacy sub-TLVs . . . . . . . . . . . . . . . . . . . . . 5 3.1. Legacy sub-TLVs . . . . . . . . . . . . . . . . . . . . . 5
3.2. Legacy SRLG Advertisements . . . . . . . . . . . . . . . 5 3.2. Legacy SRLG Advertisements . . . . . . . . . . . . . . . 6
4. Advertising Application Specific Link Attributes . . . . . . 6 4. Advertising Application Specific Link Attributes . . . . . . 6
4.1. Application Identifier Bit Mask . . . . . . . . . . . . . 6 4.1. Application Identifier Bit Mask . . . . . . . . . . . . . 6
4.2. Application Specific Link Attributes sub-TLV . . . . . . 8 4.2. Application Specific Link Attributes sub-TLV . . . . . . 9
4.2.1. Special Considerations for Maximum Link Bandwidth . . 10 4.2.1. Special Considerations for Maximum Link Bandwidth . . 10
4.2.2. Special Considerations for Reservable/Unreserved 4.2.2. Special Considerations for Reservable/Unreserved
Bandwidth . . . . . . . . . . . . . . . . . . . . . . 10 Bandwidth . . . . . . . . . . . . . . . . . . . . . . 10
4.2.3. Considerations for Extended TE Metrics . . . . . . . 10 4.2.3. Considerations for Extended TE Metrics . . . . . . . 10
4.3. Application Specific SRLG TLV . . . . . . . . . . . . . . 11 4.3. Application Specific SRLG TLV . . . . . . . . . . . . . . 11
5. Attribute Advertisements and Enablement . . . . . . . . . . . 12 5. Attribute Advertisements and Enablement . . . . . . . . . . . 12
6. Deployment Considerations . . . . . . . . . . . . . . . . . . 13 6. Deployment Considerations . . . . . . . . . . . . . . . . . . 13
6.1. Use of Legacy Advertisements . . . . . . . . . . . . . . 13 6.1. Use of Legacy Advertisements . . . . . . . . . . . . . . 13
6.2. Use of Zero Length Application Identifier Bit Masks . . . 13 6.2. Use of Zero Length Application Identifier Bit Masks . . . 14
6.3. Interoperability, Backwards Compatibility and Migration 6.3. Interoperability, Backwards Compatibility and Migration
Concerns . . . . . . . . . . . . . . . . . . . . . . . . 14 Concerns . . . . . . . . . . . . . . . . . . . . . . . . 14
6.3.1. Multiple Applications: Common Attributes with RSVP- 6.3.1. Multiple Applications: Common Attributes with RSVP-
TE . . . . . . . . . . . . . . . . . . . . . . . . . 14 TE . . . . . . . . . . . . . . . . . . . . . . . . . 14
6.3.2. Multiple Applications: All Attributes Not Shared with 6.3.2. Multiple Applications: All Attributes Not Shared with
RSVP-TE . . . . . . . . . . . . . . . . . . . . . . . 14 RSVP-TE . . . . . . . . . . . . . . . . . . . . . . . 14
6.3.3. Interoperability with Legacy Routers . . . . . . . . 15 6.3.3. Interoperability with Legacy Routers . . . . . . . . 15
6.3.4. Use of Application Specific Advertisements for RSVP- 6.3.4. Use of Application Specific Advertisements for RSVP-
TE . . . . . . . . . . . . . . . . . . . . . . . . . 15 TE . . . . . . . . . . . . . . . . . . . . . . . . . 15
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 16 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 16
7.1. Application Specific Link Attributes sub-TLV . . . . . . 16 7.1. Application Specific Link Attributes sub-TLV . . . . . . 16
7.2. Application Specific SRLG TLV . . . . . . . . . . . . . . 16 7.2. Application Specific SRLG TLV . . . . . . . . . . . . . . 16
7.3. Application Specific Link Attributes sub-sub-TLV Registry 16 7.3. Application Specific Link Attributes sub-sub-TLV Registry 16
7.4. Link Attribute Application Identifier Registry . . . . . 17 7.4. Link Attribute Application Identifier Registry . . . . . 17
7.5. SRLG sub-TLVs . . . . . . . . . . . . . . . . . . . . . . 18 7.5. SRLG sub-TLVs . . . . . . . . . . . . . . . . . . . . . . 18
8. Security Considerations . . . . . . . . . . . . . . . . . . . 18 8. Security Considerations . . . . . . . . . . . . . . . . . . . 18
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 19 9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 19
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 19 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 19
10.1. Normative References . . . . . . . . . . . . . . . . . . 19 10.1. Normative References . . . . . . . . . . . . . . . . . . 19
10.2. Informative References . . . . . . . . . . . . . . . . . 20 10.2. Informative References . . . . . . . . . . . . . . . . . 20
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 20 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 21
1. Introduction 1. Introduction
Advertisement of link attributes by the Intermediate-System-to- Advertisement of link attributes by the Intermediate-System-to-
Intermediate-System (IS-IS) protocol in support of traffic Intermediate-System (IS-IS) protocol in support of traffic
engineering (TE) was introduced by [RFC5305] and extended by engineering (TE) was introduced by [RFC5305] and extended by
[RFC5307], [RFC6119], [RFC7308], and [RFC8570]. Use of these [RFC5307], [RFC6119], [RFC7308], and [RFC8570]. Use of these
extensions has been associated with deployments supporting Traffic extensions has been associated with deployments supporting Traffic
Engineering over Multiprotocol Label Switching (MPLS) in the presence Engineering over Multiprotocol Label Switching (MPLS) in the presence
of the Resource Reservation Protocol (RSVP) - more succinctly of the Resource Reservation Protocol (RSVP) - more succinctly
referred to as RSVP-TE [RFC3209]. referred to as RSVP-TE [RFC3209].
For the purposes of this document an application is a technology For the purposes of this document an application is a technology that
which makes use of link attribute advertisements - examples of which makes use of link attribute advertisements - examples of which are
are listed in Section 3. listed in Section 3.
In recent years new applications have been introduced which have use In recent years new applications that have use cases for many of the
cases for many of the link attributes historically used by RSVP-TE. link attributes historically used by RSVP-TE have been introduced.
Such applications include Segment Routing Traffic Engineering (SRTE) Such applications include Segment Routing Policy (SR Policy)
[I-D.ietf-spring-segment-routing-policy] and Loop Free Alternates [I-D.ietf-spring-segment-routing-policy] and Loop Free Alternates
(LFA) [RFC5286]. This has introduced ambiguity in that if a (LFA) [RFC5286]. This has introduced ambiguity in that if a
deployment includes a mix of RSVP-TE support and SRTE support (for deployment includes a mix of RSVP-TE support and SR Policy support
example) it is not possible to unambiguously indicate which (for example) it is not possible to unambiguously indicate which
advertisements are to be used by RSVP-TE and which advertisements are advertisements are to be used by RSVP-TE and which advertisements are
to be used by SRTE. If the topologies are fully congruent this may to be used by SR Policy. If the topologies are fully congruent this
not be an issue, but any incongruence leads to ambiguity. may not be an issue, but any incongruence leads to ambiguity.
An additional issue arises in cases where both applications are An additional issue arises in cases where both applications are
supported on a link but the link attribute values associated with supported on a link but the link attribute values associated with
each application differ. Current advertisements do not support each application differ. Current advertisements do not support
advertising application specific values for the same attribute on a advertising application specific values for the same attribute on a
specific link. specific link.
This document defines extensions which address these issues. Also, This document defines extensions that address these issues. Also, as
as evolution of use cases for link attributes can be expected to evolution of use cases for link attributes can be expected to
continue in the years to come, this document defines a solution which continue in the years to come, this document defines a solution that
is easily extensible to the introduction of new applications and new is easily extensible to the introduction of new applications and new
use cases. use cases.
2. Requirements Discussion 2. Requirements Discussion
As stated previously, evolution of use cases for link attributes can As stated previously, evolution of use cases for link attributes can
be expected to continue - so any discussion of existing use cases is be expected to continue. Therefore, any discussion of existing use
limited to requirements which are known at the time of this writing. cases is limited to requirements that are known at the time of this
However, in order to determine the functionality required beyond what writing. However, in order to determine the functionality required
already exists in IS-IS, it is only necessary to discuss use cases beyond what already exists in IS-IS, it is only necessary to discuss
which justify the key points identified in the introduction - which use cases that justify the key points identified in the introduction,
are: which are:
1. Support for indicating which applications are using the link 1. Support for indicating which applications are using the link
attribute advertisements on a link attribute advertisements on a link
2. Support for advertising application specific values for the same 2. Support for advertising application specific values for the same
attribute on a link attribute on a link
[RFC7855] discusses use cases/requirements for Segment Routing (SR). [RFC7855] discusses use cases/requirements for Segment Routing (SR).
Included among these use cases is SRTE which is defined in Included among these use cases is SR Policy which is defined in
[I-D.ietf-spring-segment-routing-policy]. If both RSVP-TE and SRTE [I-D.ietf-spring-segment-routing-policy]. If both RSVP-TE and SR
are deployed in a network, link attribute advertisements can be used Policy are deployed in a network, link attribute advertisements can
by one or both of these applications. As there is no requirement for be used by one or both of these applications. As there is no
the link attributes advertised on a given link used by SRTE to be requirement for the link attributes advertised on a given link used
identical to the link attributes advertised on that same link used by by SR Policy to be identical to the link attributes advertised on
RSVP-TE, there is a clear requirement to indicate independently which that same link used by RSVP-TE, there is a clear requirement to
link attribute advertisements are to be used by each application. indicate independently which link attribute advertisements are to be
used by each application.
As the number of applications which may wish to utilize link As the number of applications that may wish to utilize link
attributes may grow in the future, an additional requirement is that attributes may grow in the future, an additional requirement is that
the extensions defined allow the association of additional the extensions defined allow the association of additional
applications to link attributes without altering the format of the applications to link attributes without altering the format of the
advertisements or introducing new backwards compatibility issues. advertisements or introducing new backwards compatibility issues.
Finally, there may still be many cases where a single attribute value Finally, there may still be many cases where a single attribute value
can be shared among multiple applications, so the solution must can be shared among multiple applications, so the solution must
minimize advertising duplicate link/attribute pairs whenever minimize advertising duplicate link/attribute pairs whenever
possible. possible.
3. Legacy Advertisements 3. Legacy Advertisements
There are existing advertisements used in support of RSVP-TE. These There are existing advertisements used in support of RSVP-TE. These
advertisements include sub-TLVs for TLVs 22, 23, 25, 141, 222, and advertisements include sub-TLVs for TLVs 22, 23, 25, 141, 222, and
223 and TLVs for Shared Risk Link Group (SRLG) advertisement. 223 and TLVs for Shared Risk Link Group (SRLG) advertisement.
Sub-TLV values are defined in https://www.iana.org/assignments/isis- Sub-TLV values are defined in the Sub-TLVs for TLVs 22, 23, 25, 141,
tlv-codepoints/isis-tlv-codepoints.xhtml#isis-tlv-codepoints- 222, and 223 registry.
22-23-25-141-222-223 and https://www.iana.org/assignments/isis-tlv-
codepoints/isis-tlv-codepoints.xhtml . TLVs are defined in the TLV Codepoints Registry.
3.1. Legacy sub-TLVs 3.1. Legacy sub-TLVs
Sub-TLVs for TLVs 22, 23, 25, 141, 222, and 223 Sub-TLVs for TLVs 22, 23, 25, 141, 222, and 223
+-------------------------------------------+ +-------------------------------------------+
| Type | Description | | Type | Description |
+-------------------------------------------+ +-------------------------------------------+
| 3 | Administrative group (color) | | 3 | Administrative group (color) |
+-------------------------------------------+ +-------------------------------------------+
skipping to change at page 6, line 26 skipping to change at page 6, line 29
Two new code points are defined in support of Application Specific Two new code points are defined in support of Application Specific
Link Attribute Advertisements: Link Attribute Advertisements:
1) Application Specific Link Attributes sub-TLV for TLVs 22, 23, 25, 1) Application Specific Link Attributes sub-TLV for TLVs 22, 23, 25,
141, 222, and 223 (defined in Section 4.2 ). 141, 222, and 223 (defined in Section 4.2 ).
2)Application Specific Shared Risk Link Group (SRLG) TLV (defined in 2)Application Specific Shared Risk Link Group (SRLG) TLV (defined in
Section 4.3). Section 4.3).
In support of these new advertisements, an application identifier bit In support of these new advertisements, an application identifier bit
mask is defined which identifies the application(s) associated with a mask is defined that identifies the application(s) associated with a
given advertisement (defined in Section 4.1). given advertisement (defined in Section 4.1).
The following sections define the format of these new advertisements. The following sections define the format of these new advertisements.
4.1. Application Identifier Bit Mask 4.1. Application Identifier Bit Mask
Identification of the set of applications associated with link Identification of the set of applications associated with link
attribute advertisements utilizes two bit masks. One bit mask is for attribute advertisements utilizes two bit masks. One bit mask is for
standard applications where the definition of each bit is defined in standard applications where the definition of each bit is defined in
a new IANA controlled registry. A second bit mask is for non- a new IANA controlled registry. A second bit mask is for non-
skipping to change at page 7, line 16 skipping to change at page 7, line 18
SABM Length + Flag (1 octet) SABM Length + Flag (1 octet)
Standard Application Identifier Bit Mask Standard Application Identifier Bit Mask
Length + Flag Length + Flag
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
|L| SABM Length | |L| SABM Length |
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
L-flag: Legacy Flag. L-flag: Legacy Flag.
See the following section for a description of how See Section 4.2 for a description of how
this flag is used. this flag is used.
SABM Length: Indicates the length in octets (0-8) of the SABM Length: Indicates the length in octets (0-8) of the
Standard Application Identifier Bit Mask. The length SHOULD Standard Application Identifier Bit Mask. The length SHOULD
be the minimum required to send all bits which are set. be the minimum required to send all bits that are set.
UDABM Length + Flag (1 octet) UDABM Length + Flag (1 octet)
User Defined Application Identifier Bit Mask User Defined Application Identifier Bit Mask
Length + Flag Length + Flag
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
|R| UDABM Length| |R| UDABM Length|
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
R: Reserved. SHOULD be transmitted as 0 and R: Reserved. SHOULD be transmitted as 0 and
MUST be ignored on receipt MUST be ignored on receipt
UDABM Length: Indicates the length in octets (0-8) of the UDABM Length: Indicates the length in octets (0-8) of the
User Defined Application Identifier Bit Mask. The length SHOULD User Defined Application Identifier Bit Mask. The length SHOULD
be the minimum required to send all bits which are set. be the minimum required to send all bits that are set.
SABM (variable length) SABM (variable length)
Standard Application Identifier Bit Mask Standard Application Identifier Bit Mask
(SABM Length * 8) bits (SABM Length * 8) bits
This field is omitted if SABM Length is 0. This field is omitted if SABM Length is 0.
0 1 2 3 4 5 6 7 ... 0 1 2 3 4 5 6 7 ...
+-+-+-+-+-+-+-+-+... +-+-+-+-+-+-+-+-+...
skipping to change at page 7, line 49 skipping to change at page 8, line 4
SABM (variable length) SABM (variable length)
Standard Application Identifier Bit Mask Standard Application Identifier Bit Mask
(SABM Length * 8) bits (SABM Length * 8) bits
This field is omitted if SABM Length is 0. This field is omitted if SABM Length is 0.
0 1 2 3 4 5 6 7 ... 0 1 2 3 4 5 6 7 ...
+-+-+-+-+-+-+-+-+... +-+-+-+-+-+-+-+-+...
|R|S|F| ... |R|S|F| ...
+-+-+-+-+-+-+-+-+... +-+-+-+-+-+-+-+-+...
R-bit: Set to specify RSVP-TE R-bit: Set to specify RSVP-TE
S-bit: Set to specify Segment Routing S-bit: Set to specify Segment Routing Policy
Traffic Engineering (SRTE)
F-bit: Set to specify Loop Free Alternate (LFA) F-bit: Set to specify Loop Free Alternate (LFA)
(includes all LFA types) (includes all LFA types)
UDABM (variable length) UDABM (variable length)
User Defined Application Identifier Bit Mask User Defined Application Identifier Bit Mask
(UDABM Length * 8) bits (UDABM Length * 8) bits
0 1 2 3 4 5 6 7 ... 0 1 2 3 4 5 6 7 ...
skipping to change at page 8, line 30 skipping to change at page 8, line 31
| ... | ...
+-+-+-+-+-+-+-+-+... +-+-+-+-+-+-+-+-+...
This field is omitted if UDABM Length is 0. This field is omitted if UDABM Length is 0.
NOTE: SABM/UDABM Length is arbitrarily limited to 8 octets in order NOTE: SABM/UDABM Length is arbitrarily limited to 8 octets in order
to insure that sufficient space is left to advertise link attributes to insure that sufficient space is left to advertise link attributes
without overrunning the maximum length of a sub-TLV. without overrunning the maximum length of a sub-TLV.
Standard Application Identifier Bits are defined/sent starting with Standard Application Identifier Bits are defined/sent starting with
Bit 0. Undefined bits which are transmitted MUST be transmitted as 0 Bit 0.
and MUST be ignored on receipt. Bits that are not transmitted MUST
be treated as if they are set to 0 on receipt. Bits that are not
supported by an implementation MUST be ignored on receipt.
User Defined Application Identifier Bits have no relationship to User Defined Application Identifier Bits have no relationship to
Standard Application Identifier Bits and are not managed by IANA or Standard Application Identifier Bits and are not managed by IANA or
any other standards body. It is recommended that bits are used any other standards body. It is recommended that bits are used
starting with Bit 0 so as to minimize the number of octets required starting with Bit 0 so as to minimize the number of octets required
to advertise all UDAs. to advertise all UDAs.
In the case of both SABM and UDABM, the following rules apply:
o Undefined bits that are transmitted MUST be transmitted as 0 and
MUST be ignored on receipt
o Bits that are not transmitted MUST be treated as if they are set
to 0 on receipt.
o Bits that are not supported by an implementation MUST be ignored
on receipt.
.
4.2. Application Specific Link Attributes sub-TLV 4.2. Application Specific Link Attributes sub-TLV
A new sub-TLV for TLVs 22, 23, 25, 141, 222, and 223 is defined which A new sub-TLV for TLVs 22, 23, 25, 141, 222, and 223 is defined that
supports specification of the applications and application specific supports specification of the applications and application specific
attribute values. attribute values.
Type: 16 (temporarily assigned by IANA) Type: 16 (temporarily assigned by IANA)
Length: Variable (1 octet) Length: Variable (1 octet)
Value: Value:
Application Identifier Bit Mask Application Identifier Bit Mask
(as defined in Section 4.1) (as defined in Section 4.1)
Link Attribute sub-sub-TLVs - format matches the Link Attribute sub-sub-TLVs - format matches the
existing formats defined in [RFC5305], [RFC7308], existing formats defined in [RFC5305], [RFC7308],
and [RFC8570] and [RFC8570]
If the SABM or UDABM length in the Application Identifer Bit Mask is If the SABM or UDABM length in the Application Identifier Bit Mask is
greater than 8, the entire sub-TLV MUST be ignored. greater than 8, the entire sub-TLV MUST be ignored.
When the L-flag is set in the Application Identifier Bit Mask, all of When the L-flag is set in the Application Identifier Bit Mask, all of
the applications specified in the bit mask MUST use the legacy the applications specified in the bit mask MUST use the legacy
advertisements for the corresponding link found in TLVs 22, 23, 25, advertisements for the corresponding link found in TLVs 22, 23, 25,
141, 222, and 223 or TLV 138 or TLV 139 as appropriate. Link 141, 222, and 223 or TLV 138 or TLV 139 as appropriate. Link
attribute sub-sub-TLVs for the corresponding link attributes MUST NOT attribute sub-sub-TLVs for the corresponding link attributes MUST NOT
be advertised for the set of applications specified in the Standard/ be advertised for the set of applications specified in the Standard/
User Application Identifier Bit Masks and all such advertisements User Application Identifier Bit Masks and all such advertisements
MUST be ignored on receipt. MUST be ignored on receipt.
skipping to change at page 9, line 46 skipping to change at page 9, line 52
For a given application, the setting of the L-flag MUST be the same For a given application, the setting of the L-flag MUST be the same
in all sub-TLVs for a given link. In cases where this constraint is in all sub-TLVs for a given link. In cases where this constraint is
violated, the L-flag MUST be considered set for this application. violated, the L-flag MUST be considered set for this application.
If link attributes are advertised associated with zero length If link attributes are advertised associated with zero length
Application Identifier Bit Masks for both standard applications and Application Identifier Bit Masks for both standard applications and
user defined applications, then any Standard Application and/or any user defined applications, then any Standard Application and/or any
User Defined Application is permitted to use that set of link User Defined Application is permitted to use that set of link
attributes so long as there is not another set of attributes attributes so long as there is not another set of attributes
advertised on that same link which is associated with a non-zero advertised on that same link that is associated with a non-zero
length Application Identifier Bit Mask with a matching Application length Application Identifier Bit Mask with a matching Application
Identifier Bit set. Identifier Bit set.
A new registry of sub-sub-TLVs is to be created by IANA which defines A new registry of sub-sub-TLVs is to be created by IANA that defines
the link attribute sub-sub-TLV code points. This document defines a the link attribute sub-sub-TLV code points. This document defines a
sub-sub-TLV for each of the existing sub-TLVs listed in Section 3.1 sub-sub-TLV for each of the existing sub-TLVs listed in Section 3.1
except as noted below. The format of the sub-sub-TLVs matches the except as noted below. The format of the sub-sub-TLVs matches the
format of the corresponding legacy sub-TLV and IANA is requested to format of the corresponding legacy sub-TLV and IANA is requested to
assign the legacy sub-TLV identifier to the corresponding sub-sub- assign the legacy sub-TLV identifier to the corresponding sub-sub-
TLV. TLV.
4.2.1. Special Considerations for Maximum Link Bandwidth 4.2.1. Special Considerations for Maximum Link Bandwidth
Maximum link bandwidth is an application independent attribute of the Maximum link bandwidth is an application independent attribute of the
link. When advertised using the Application Specific Link Attributes link. When advertised using the Application Specific Link Attributes
sub-TLV, multiple values for the same link MUST NOT be advertised. sub-TLV, multiple values for the same link MUST NOT be advertised.
This can be accomplished most efficiently by having a single This can be accomplished most efficiently by having a single
advertisement for a given link where the Application Identifier Bit advertisement for a given link where the Application Identifier Bit
Mask identifies all the applications which are making use of the Mask identifies all the applications that are making use of the value
value for that link. for that link.
It is also possible to advertise the same value for a given link It is also possible to advertise the same value for a given link
multiple times with disjoint sets of applications specified in the multiple times with disjoint sets of applications specified in the
Application Identifier Bit Mask. This is less efficient but still Application Identifier Bit Mask. This is less efficient but still
valid. valid.
It is also possible to advertise a single advertisement with zero
length SABM and UDABM so long as the constraints discussed in
Section 4.2 and Section 6.2 are acceptable.
If different values for Maximum Link Bandwidth for a given link are If different values for Maximum Link Bandwidth for a given link are
advertised, all values MUST be ignored. advertised, all values MUST be ignored.
4.2.2. Special Considerations for Reservable/Unreserved Bandwidth 4.2.2. Special Considerations for Reservable/Unreserved Bandwidth
Maximum Reservable Link Bandwidth and Unreserved Bandwidth are Maximum Reservable Link Bandwidth and Unreserved Bandwidth are
attributes specific to RSVP-TE. When advertised using the attributes specific to RSVP-TE. When advertised using the
Application Specific Link Attributes sub-TLV, bits other than the Application Specific Link Attributes sub-TLV, bits other than the
RSVP-TE (R-bit) MUST NOT be set in the Application Identifier Bit RSVP-TE (R-bit) MUST NOT be set in the Application Identifier Bit
Mask. If an advertisement of Maximum Reservable Link Bandwidth or Mask. If an advertisement of Maximum Reservable Link Bandwidth or
skipping to change at page 11, line 37 skipping to change at page 11, line 47
sub-TLVs from [RFC5305], [RFC5307], and [RFC6119]. sub-TLVs from [RFC5305], [RFC5307], and [RFC6119].
Type Description Type Description
4 Link Local/Remote Identifiers [RFC5307] 4 Link Local/Remote Identifiers [RFC5307]
6 IPv4 interface address [RFC5305] 6 IPv4 interface address [RFC5305]
8 IPv4 neighbor address [RFC5305] 8 IPv4 neighbor address [RFC5305]
12 IPv6 Interface Address [RFC6119] 12 IPv6 Interface Address [RFC6119]
13 IPv6 Neighbor Address [RFC6119] 13 IPv6 Neighbor Address [RFC6119]
At least one set of link identifiers (IPv4, IPv6, or Link Local/ At least one set of link identifiers (IPv4, IPv6, or Link Local/
Remote) MUST be present. TLVs which do not meet this requirement Remote) MUST be present. Multiple occurrences of the same identifier
type MUST NOT be present. TLVs that do not meet this requirement
MUST be ignored. MUST be ignored.
Multiple TLVs for the same link MAY be advertised. Multiple TLVs for the same link MAY be advertised.
When the L-flag is set in the Application Identifier Bit Mask, SRLG When the L-flag is set in the Application Identifier Bit Mask, SRLG
values MUST NOT be included in the TLV. Any SRLG values which are values MUST NOT be included in the TLV. Any SRLG values that are
advertised MUST be ignored. Based on the link identifiers advertised advertised MUST be ignored. Based on the link identifiers advertised
the corresponding legacy TLV (see Section 3.2) can be identified and the corresponding legacy TLV (see Section 3.2) can be identified and
the SRLG values advertised in the legacy TLV MUST be used by the set the SRLG values advertised in the legacy TLV MUST be used by the set
of applications specified in the Application Identifier Bit Mask. of applications specified in the Application Identifier Bit Mask.
For a given application, the setting of the L-flag MUST be the same For a given application, the setting of the L-flag MUST be the same
in all TLVs for a given link. In cases where this constraint is in all TLVs for a given link. In cases where this constraint is
violated, the L-flag MUST be considered set for this application. violated, the L-flag MUST be considered set for this application.
5. Attribute Advertisements and Enablement 5. Attribute Advertisements and Enablement
skipping to change at page 12, line 22 skipping to change at page 12, line 33
depends upon the application. Similarly, whether the absence of link depends upon the application. Similarly, whether the absence of link
attribute advertisements indicates that the application is not attribute advertisements indicates that the application is not
enabled depends upon the application. enabled depends upon the application.
In the case of RSVP-TE, the advertisement of application specific In the case of RSVP-TE, the advertisement of application specific
link attributes implies that RSVP is enabled on that link. The link attributes implies that RSVP is enabled on that link. The
absence of RSVP-TE application specific link attributes in absence of RSVP-TE application specific link attributes in
combination with the absence of legacy advertisements implies that combination with the absence of legacy advertisements implies that
RSVP is not enabled on that link. RSVP is not enabled on that link.
In the case of SRTE, advertisement of application specific link In the case of SR Policy, advertisement of application specific link
attributes does not indicate enablement of SRTE on that link. The attributes does not indicate enablement of SR Policy on that link.
advertisements are only used to support constraints which may be The advertisements are only used to support constraints that may be
applied when specifying an explicit path. SRTE is implicitly enabled applied when specifying an explicit path. SR Policy is implicitly
on all links which are part of the Segment Routing enabled topology enabled on all links that are part of the Segment Routing enabled
independent of the existence of link attribute advertisements topology independent of the existence of link attribute
advertisements.
In the case of LFA, advertisement of application specific link In the case of LFA, advertisement of application specific link
attributes does not indicate enablement of LFA on that link. attributes does not indicate enablement of LFA on that link.
Enablement is controlled by local configuration. Enablement is controlled by local configuration.
If, in the future, additional standard applications are defined to If, in the future, additional standard applications are defined to
use this mechanism, the specification defining this use MUST define use this mechanism, the specification defining this use MUST define
the relationship between application specific link attribute the relationship between application specific link attribute
advertisements and enablement for that application. advertisements and enablement for that application.
skipping to change at page 13, line 14 skipping to change at page 13, line 22
6. Deployment Considerations 6. Deployment Considerations
This section discuss deployment considerations associated with the This section discuss deployment considerations associated with the
use of application specific link attribute advertisements. use of application specific link attribute advertisements.
6.1. Use of Legacy Advertisements 6.1. Use of Legacy Advertisements
Bit Identifiers for Standard Applications are defined in Section 4.1. Bit Identifiers for Standard Applications are defined in Section 4.1.
All of the identifiers defined in this document are associated with All of the identifiers defined in this document are associated with
applications which were already deployed in some networks prior to applications that were already deployed in some networks prior to the
the writing of this document. Therefore, such applications have been writing of this document. Therefore, such applications have been
deployed using the legacy advertisements. The Standard Applications deployed using the legacy advertisements. The Standard Applications
defined in this document may continue to use legacy advertisements defined in this document may continue to use legacy advertisements
for a given link so long as at least one of the following conditions for a given link so long as at least one of the following conditions
is true: is true:
o The application is RSVP-TE o The application is RSVP-TE
o The application is SRTE or LFA and RSVP-TE is not deployed o The application is SR Policy or LFA and RSVP-TE is not deployed
anywhere in the network anywhere in the network
o The application is SRTE or LFA, RSVP-TE is deployed in the o The application is SR Policy or LFA, RSVP-TE is deployed in the
network, and both the set of links on which SRTE and/or LFA network, and both the set of links on which SR Policy and/or LFA
advertisements are required and the attribute values used by SRTE advertisements are required and the attribute values used by SR
and/or LFA on all such links is fully congruent with the links and Policy and/or LFA on all such links is fully congruent with the
attribute values used by RSVP-TE links and attribute values used by RSVP-TE
Under the conditions defined above, implementations which support the Under the conditions defined above, implementations that support the
extensions defined in this document have the choice of using legacy extensions defined in this document have the choice of using legacy
advertisements or application specific advertisements in support of advertisements or application specific advertisements in support of
SRTE and/or LFA. This will require implementations to provide SR Policy and/or LFA. This will require implementations to provide
controls specifying which type of advertisements are to be sent/ controls specifying which type of advertisements are to be sent/
processed on receive for these applications. Further discussion of processed on receive for these applications. Further discussion of
the associated issues can be found in Section 6.3. the associated issues can be found in Section 6.3.
New applications which future documents define to make use of the New applications that future documents define to make use of the
advertisements defined in this document MUST NOT make use of legacy advertisements defined in this document MUST NOT make use of legacy
advertisements. This simplifies deployment of new applications by advertisements. This simplifies deployment of new applications by
eliminating the need to support multiple ways to advertise attributes eliminating the need to support multiple ways to advertise attributes
for the new applications. for the new applications.
6.2. Use of Zero Length Application Identifier Bit Masks 6.2. Use of Zero Length Application Identifier Bit Masks
Link attribute advertisements associated with zero length Application Link attribute advertisements associated with zero length Application
Identifier Bit Masks for both standard applications and user defined Identifier Bit Masks for both standard applications and user defined
applications are usable by any application, subject to the applications are usable by any application, subject to the
restrictions specified in Section 4.2. If support for a new restrictions specified in Section 4.2. If support for a new
application is introduced on any node in a network in the presence of application is introduced on any node in a network in the presence of
such advertisements, these advertisements are permitted to be used by such advertisements, these advertisements are permitted to be used by
the new application. If this is not what is intended, then existing the new application. If this is not what is intended, then existing
advertisements MUST be readvertised with an explicit set of advertisements MUST be readvertised with an explicit set of
applications specified before a new application is introduced. applications specified before a new application is introduced.
6.3. Interoperability, Backwards Compatibility and Migration Concerns 6.3. Interoperability, Backwards Compatibility and Migration Concerns
Existing deployments of RSVP-TE, SRTE, and/or LFA utilize the legacy Existing deployments of RSVP-TE, SR Policy, and/or LFA utilize the
advertisements listed in Section 3. Routers which do not support the legacy advertisements listed in Section 3. Routers that do not
extensions defined in this document will only process legacy support the extensions defined in this document will only process
advertisements and are likely to infer that RSVP-TE is enabled on the legacy advertisements and are likely to infer that RSVP-TE is enabled
links for which legacy advertisements exist. It is expected that on the links for which legacy advertisements exist. It is expected
deployments using the legacy advertisements will persist for a that deployments using the legacy advertisements will persist for a
significant period of time. Therefore deployments using the significant period of time. Therefore deployments using the
extensions defined in this document in the presence of routers which extensions defined in this document in the presence of routers that
do not support these extensions need to be able to interoperate with do not support these extensions need to be able to interoperate with
the use of legacy advertisements by the legacy routers. The the use of legacy advertisements by the legacy routers. The
following sub-sections discuss interoperability and backwards following sub-sections discuss interoperability and backwards
compatibility concerns for a number of deployment scenarios. compatibility concerns for a number of deployment scenarios.
6.3.1. Multiple Applications: Common Attributes with RSVP-TE 6.3.1. Multiple Applications: Common Attributes with RSVP-TE
In cases where multiple applications are utilizing a given link, one In cases where multiple applications are utilizing a given link, one
of the applications is RSVP-TE, and all link attributes for a given of the applications is RSVP-TE, and all link attributes for a given
link are common to the set of applications utilizing that link, link are common to the set of applications utilizing that link,
skipping to change at page 14, line 41 skipping to change at page 14, line 51
link attribute values. This avoids duplication of link attribute link attribute values. This avoids duplication of link attribute
advertisements. advertisements.
6.3.2. Multiple Applications: All Attributes Not Shared with RSVP-TE 6.3.2. Multiple Applications: All Attributes Not Shared with RSVP-TE
In cases where one or more applications other than RSVP-TE are In cases where one or more applications other than RSVP-TE are
utilizing a given link and one or more link attribute values are not utilizing a given link and one or more link attribute values are not
shared with RSVP-TE, it is necessary to use application specific shared with RSVP-TE, it is necessary to use application specific
advertisements as defined in this document. Attributes for advertisements as defined in this document. Attributes for
applications other than RSVP-TE MUST be advertised using application applications other than RSVP-TE MUST be advertised using application
specific advertisements which have the L-flag clear. In cases where specific advertisements that have the L-flag clear. In cases where
some link attributes are shared with RSVP-TE, this requires duplicate some link attributes are shared with RSVP-TE, this requires duplicate
advertisements for those attributes. advertisements for those attributes.
The discussion in this section applies to cases where RSVP-TE is not These guidelines apply to cases where RSVP-TE is not using any
using any advertised attributes on a link and to cases where RSVP-TE advertised attributes on a link and to cases where RSVP-TE is using
is using some link attribute advertisements on the link but some link some link attribute advertisements on the link but some link
attributes cannot be shared with RSVP-TE. attributes cannot be shared with RSVP-TE.
6.3.3. Interoperability with Legacy Routers 6.3.3. Interoperability with Legacy Routers
For the applications defined in this document, routers which do not For the applications defined in this document, routers that do not
support the extensions defined in this document will send and receive support the extensions defined in this document will send and receive
only legacy link attribute advertisements. So long as there is any only legacy link attribute advertisements. So long as there is any
legacy router in the network which has any of the applications legacy router in the network that has any of the applications
enabled, all routers MUST continue to advertise link attributes using enabled, all routers MUST continue to advertise link attributes using
legacy advertisements. In addition, the link attribute values legacy advertisements. In addition, the link attribute values
associated with the set of applications supported by legacy routers associated with the set of applications supported by legacy routers
(RSVP-TE, SRTE, and/or LFA) are always shared since legacy routers (RSVP-TE, SR Policy, and/or LFA) are always shared since legacy
have no way of advertising or processing application specific values. routers have no way of advertising or processing application specific
Once all legacy routers have been upgraded, migration from legacy values. Once all legacy routers have been upgraded, migration from
advertisements to application specific advertisements can be achieved legacy advertisements to application specific advertisements can be
via the following steps: achieved via the following steps:
1)Send application specific advertisements while continuing to 1)Send application specific advertisements while continuing to
advertise using legacy (all advertisements are then duplicated). advertise using legacy (all advertisements are then duplicated).
Receiving routers continue to use legacy advertisements. Receiving routers continue to use legacy advertisements.
2)Enable the use of the application specific advertisements on all 2)Enable the use of the application specific advertisements on all
routers routers
3)Remove legacy advertisements 3)Remove legacy advertisements
When the migration is complete, it then becomes possible to advertise When the migration is complete, it then becomes possible to advertise
incongruent values per application on a given link. incongruent values per application on a given link.
Note that the use of the L-flag is of no value in the migration. Note that the use of the L-flag is of no value in the migration.
Documents defining new applications which make use of the application Documents defining new applications that make use of the application
specific advertisements defined in this document MUST discuss specific advertisements defined in this document MUST discuss
interoperability and backwards compatibility issues that could occur interoperability and backwards compatibility issues that could occur
in the presence of routers which do not support the new application. in the presence of routers that do not support the new application.
6.3.4. Use of Application Specific Advertisements for RSVP-TE 6.3.4. Use of Application Specific Advertisements for RSVP-TE
The extensions defined in this document support RSVP-TE as one of the The extensions defined in this document support RSVP-TE as one of the
supported applications. This allows that RSVP-TE could eventually supported applications. This allows that RSVP-TE could eventually
utilize the application specific advertisements. This can be done in utilize the application specific advertisements. This can be done in
the following step-wise manner: the following step-wise manner:
1)Upgrade all routers to support the extensions in this document 1)Upgrade all routers to support the extensions in this document
2)Advertise all legacy link attributes using application specific 2)Advertise all legacy link attributes using application specific
advertisements with L-flag clear and R-bit set. advertisements with L-flag clear and R-bit set. At this point both
legacy and application specific advertisements are being sent.
3)Remove legacy advertisements 3)Remove legacy advertisements
7. IANA Considerations 7. IANA Considerations
This section lists the protocol code point changes introduced by this This section lists the protocol code point changes introduced by this
document and the related IANA changes required. document and the related IANA changes required.
For new registries defined under IS-IS TLV Codepoints Registry with For new registries defined under IS-IS TLV Codepoints Registry with
registration procedure "Expert Review", guidance for designated registration procedure "Expert Review", guidance for designated
experts can be found in [RFC7370]. experts can be found in [RFC7370].
7.1. Application Specific Link Attributes sub-TLV 7.1. Application Specific Link Attributes sub-TLV
This document defines a new sub-TLV in the Sub-TLVs for TLVs 22, 23, This document defines a new sub-TLV in the Sub-TLVs for TLVs 22, 23,
25, 141, 222, and 223 registry. 25, 141, 222, and 223 registry. See Section 4.2
Type Description 22 23 25 141 222 223 Type Description 22 23 25 141 222 223
---- --------------------- ---- ---- ---- ---- ---- ---- ---- --------------------- ---- ---- ---- ---- ---- ----
16 Application Specific y y y(s) y y y 16 Application Specific y y y(s) y y y
Link Attributes Link Attributes
7.2. Application Specific SRLG TLV 7.2. Application Specific SRLG TLV
This document defines one new TLV in the IS-IS TLV Codepoints This document defines one new TLV in the IS-IS TLV Codepoints
Registry. Registry. See Section 4.3
Type Description IIH LSP SNP Purge Type Description IIH LSP SNP Purge
---- --------------------- --- --- --- ----- ---- --------------------- --- --- --- -----
238 Application Specific n y n n 238 Application Specific n y n n
SRLG SRLG
7.3. Application Specific Link Attributes sub-sub-TLV Registry 7.3. Application Specific Link Attributes sub-sub-TLV Registry
This document requests a new IANA registry under the IS-IS TLV This document requests a new IANA registry under the IS-IS TLV
Codepoints Registry be created to control the assignment of sub-sub- Codepoints Registry be created to control the assignment of sub-sub-
skipping to change at page 17, line 28 skipping to change at page 17, line 28
19-32 Unassigned 19-32 Unassigned
33 Unidirectional Link Delay RFC8570 33 Unidirectional Link Delay RFC8570
34 Min/Max Unidirectional Link Delay RFC8570 34 Min/Max Unidirectional Link Delay RFC8570
35 Unidirectional Delay Variation RFC8570 35 Unidirectional Delay Variation RFC8570
36 Unidirectional Link Loss RFC8570 36 Unidirectional Link Loss RFC8570
37 Unidirectional Residual Bandwidth RFC8570 37 Unidirectional Residual Bandwidth RFC8570
38 Unidirectional Available Bandwidth RFC8570 38 Unidirectional Available Bandwidth RFC8570
39 Unidirectional Utilized Bandwidth RFC8570 39 Unidirectional Utilized Bandwidth RFC8570
40-255 Unassigned 40-255 Unassigned
Note to IANA: For future codepoints, in cases where the document Note to IANA: For future codepoints, in cases where the document that
which defines the encoding is different from the document which defines the encoding is different from the document that assigns the
assigns the codepoint, the encoding reference MUST be to the document codepoint, the encoding reference MUST be to the document that
which defines the encoding. defines the encoding.
Note to designated experts: If a link attribute can be advertised Note to designated experts: If a link attribute can be advertised
both as a sub-TLV of TLVs 22, 23, 25, 141, 222, and 223 and as a sub- both as a sub-TLV of TLVs 22, 23, 25, 141, 222, and 223 and as a sub-
sub-TLV of the Application Specific Link Attributes sub-TLV defined sub-TLV of the Application Specific Link Attributes sub-TLV defined
in this document, then the same numerical code should be assigned to in this document, then the same numerical code should be assigned to
the link attribute whenever possible. the link attribute whenever possible.
7.4. Link Attribute Application Identifier Registry 7.4. Link Attribute Application Identifier Registry
This document requests a new IANA registry be created, under the This document requests a new IANA registry be created, under the
skipping to change at page 18, line 8 skipping to change at page 18, line 8
the assignment of Application Identifier Bits. The suggested name of the assignment of Application Identifier Bits. The suggested name of
the new registry is "Link Attribute Applications". The registration the new registry is "Link Attribute Applications". The registration
policy for this registry is "Standards Action" [RFC8126]. Bit policy for this registry is "Standards Action" [RFC8126]. Bit
definitions SHOULD be assigned in ascending bit order beginning with definitions SHOULD be assigned in ascending bit order beginning with
Bit 0 so as to minimize the number of octets that will need to be Bit 0 so as to minimize the number of octets that will need to be
transmitted. The following assignments are made by this document: transmitted. The following assignments are made by this document:
Bit # Name Bit # Name
--------------------------------------------------------- ---------------------------------------------------------
0 RSVP-TE (R-bit) 0 RSVP-TE (R-bit)
1 Segment Routing Traffic Engineering (S-bit) 1 Segment Routing Policy (S-bit)
2 Loop Free Alternate (F-bit) 2 Loop Free Alternate (F-bit)
3-63 Unassigned 3-63 Unassigned
7.5. SRLG sub-TLVs 7.5. SRLG sub-TLVs
This document requests a new IANA registry be created under the IS-IS This document requests a new IANA registry be created under the IS-IS
TLV Codepoints Registry to control the assignment of sub-TLV types TLV Codepoints Registry to control the assignment of sub-TLV types
for the application specific SRLG TLV. The suggested name of the new for the application specific SRLG TLV. The suggested name of the new
registry is "Sub-TLVs for TLV 238". The registration procedure is registry is "Sub-TLVs for TLV 238". The registration procedure is
"Expert Review" as defined in [RFC8126]. The following assignments "Expert Review" as defined in [RFC8126]. The following assignments
skipping to change at page 18, line 35 skipping to change at page 18, line 35
4 Link Local/Remote Identifiers [RFC5307] 4 Link Local/Remote Identifiers [RFC5307]
5 Unassigned 5 Unassigned
6 IPv4 interface address [RFC5305] 6 IPv4 interface address [RFC5305]
7 Unassigned 7 Unassigned
8 IPv4 neighbor address [RFC5305] 8 IPv4 neighbor address [RFC5305]
9-11 Unassigned 9-11 Unassigned
12 IPv6 Interface Address [RFC6119] 12 IPv6 Interface Address [RFC6119]
13 IPv6 Neighbor Address [RFC6119] 13 IPv6 Neighbor Address [RFC6119]
14-255 Unassigned 14-255 Unassigned
Note to IANA: For future codepoints, in cases where the document Note to IANA: For future codepoints, in cases where the document that
which defines the encoding is different from the document which defines the encoding is different from the document that assigns the
assigns the codepoint, the encoding reference MUST be to the document codepoint, the encoding reference MUST be to the document that
which defines the encoding. defines the encoding.
8. Security Considerations 8. Security Considerations
Security concerns for IS-IS are addressed in [ISO10589], [RFC5304], Security concerns for IS-IS are addressed in [ISO10589], [RFC5304],
and [RFC5310]. and [RFC5310]. While IS-IS is deployed under a single administrative
domain, there can be deployments where potential attackers have
access to one or more networks in the IS-IS routing domain. In these
deployments, the stronger authentication mechanisms defined in the
aforementioned documents SHOULD be used.
This document defines a new way to advertise link attributes. This document defines a new way to advertise link attributes.
Tampering with the information defined in this document may have an Tampering with the information defined in this document may have an
effect on applications using it, including impacting Traffic effect on applications using it, including impacting Traffic
Engineering. This is similar in nature to the impacts associated Engineering as discussed in [RFC8570]. As the advertisements defined
with (for example) [RFC5305]. As the advertisements defined in this in this document limit the scope to specific applications, the impact
document limit the scope to specific applications, the impact of of tampering is similarly limited in scope.
tampering is similarly limited in scope.
9. Acknowledgements 9. Acknowledgements
The authors would like to thank Eric Rosen and Acee Lindem for their The authors would like to thank Eric Rosen and Acee Lindem for their
careful review and content suggestions. careful review and content suggestions.
10. References 10. References
10.1. Normative References 10.1. Normative References
 End of changes. 59 change blocks. 
121 lines changed or deleted 142 lines changed or added

This html diff was produced by rfcdiff 1.47. The latest version is available from http://tools.ietf.org/tools/rfcdiff/