draft-ietf-isis-te-app-06.txt   draft-ietf-isis-te-app-07.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: October 10, 2019 S. Previdi Expires: April 6, 2020 S. Previdi
Huawei Huawei
W. Henderickx W. Henderickx
Nokia Nokia
J. Drake J. Drake
Juniper Networks Juniper Networks
April 8, 2019 October 4, 2019
IS-IS TE Attributes per application IS-IS TE Attributes per application
draft-ietf-isis-te-app-06.txt draft-ietf-isis-te-app-07
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. In cases have been defined and are used in RSVP-TE deployments. Since the
where multiple applications wish to make use of these link attributes original RSVP-TE use case was defined, additional applications (e.g.,
the current advertisements do not support application specific values SRTE, LFA) have been defined which also make use of the link
for a given attribute nor do they support indication of which attribute advertisements. In cases where multiple applications wish
applications are using the advertised value for a given link. to make use of these link attributes the current advertisements do
not support application specific values for a given attribute nor do
they support indication of which applications are using the
advertised value for a given link.
This draft introduces new link attribute advertisements which address This draft introduces new link attribute advertisements which address
both of these shortcomings. It also discusses backwards both of these shortcomings. It also discusses backwards
compatibility issues and how to minimize duplicate advertisements in compatibility issues and how to minimize duplicate advertisements in
the presence of routers which do not support the extensions defined the presence of routers which do not support the extensions defined
in this document. in this document.
Requirements Language Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
skipping to change at page 2, line 10 skipping to change at page 2, line 12
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 October 10, 2019. This Internet-Draft will expire on April 6, 2020.
Copyright Notice Copyright Notice
Copyright (c) 2019 IETF Trust and the persons identified as the Copyright (c) 2019 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
skipping to change at page 2, line 48 skipping to change at page 2, line 50
4.2.2. Special Considerations for Unreserved Bandwidth . . . 9 4.2.2. Special Considerations for Unreserved Bandwidth . . . 9
4.3. Application Specific SRLG TLV . . . . . . . . . . . . . . 9 4.3. Application Specific SRLG TLV . . . . . . . . . . . . . . 9
5. Deployment Considerations . . . . . . . . . . . . . . . . . . 10 5. Deployment Considerations . . . . . . . . . . . . . . . . . . 10
6. Attribute Advertisements and Enablement . . . . . . . . . . . 11 6. Attribute Advertisements and Enablement . . . . . . . . . . . 11
7. Interoperability, Backwards Compatibility and Migration 7. Interoperability, Backwards Compatibility and Migration
Concerns . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Concerns . . . . . . . . . . . . . . . . . . . . . . . . . . 12
7.1. RSVP-TE only deployments . . . . . . . . . . . . . . . . 12 7.1. RSVP-TE only deployments . . . . . . . . . . . . . . . . 12
7.2. Multiple Applications: Common Attributes with RSVP-TE . 12 7.2. Multiple Applications: Common Attributes with RSVP-TE . 12
7.3. Multiple Applications: All Attributes Not Shared w RSVP- 7.3. Multiple Applications: All Attributes Not Shared w RSVP-
TE . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 TE . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
7.4. Deprecating legacy advertisements . . . . . . . . . . . . 13 7.4. Use of Application Specific Advertisements for RSVP-TE . 13
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13
9. Security Considerations . . . . . . . . . . . . . . . . . . . 15 9. Security Considerations . . . . . . . . . . . . . . . . . . . 15
10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 15 10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 15
11. References . . . . . . . . . . . . . . . . . . . . . . . . . 15 11. References . . . . . . . . . . . . . . . . . . . . . . . . . 15
11.1. Normative References . . . . . . . . . . . . . . . . . . 15 11.1. Normative References . . . . . . . . . . . . . . . . . . 15
11.2. Informative References . . . . . . . . . . . . . . . . . 16 11.2. Informative References . . . . . . . . . . . . . . . . . 16
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 17 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 16
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], and [RFC8570]. Use of these extensions has [RFC5307], [RFC6119], and [RFC8570]. Use of these extensions has
been associated with deployments supporting Traffic Engineering over been associated with deployments supporting Traffic Engineering over
Multiprotocol Label Switching (MPLS) in the presence of Resource Multiprotocol Label Switching (MPLS) in the presence of Resource
Reservation Protocol (RSVP) - more succinctly referred to as RSVP-TE. Reservation Protocol (RSVP) - more succinctly referred to as RSVP-TE.
skipping to change at page 4, line 35 skipping to change at page 4, line 37
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, 141, 222, and 223 advertisements include sub-TLVs for TLVs 22, 23, 25, 141, 222, and
and TLVs for SRLG advertisement. 223 and TLVs for SRLG advertisement.
3.1. Legacy sub-TLVs 3.1. Legacy sub-TLVs
Sub-TLVs for TLVs 22, 23, 141, 222, and 223 Sub-TLVs for TLVs 22, 23, 25, 141, 222, and 223
Code Point/Attribute Name Code Point/Attribute Name
-------------------------- --------------------------
3 Administrative group (color) 3 Administrative group (color)
9 Maximum link bandwidth 9 Maximum link bandwidth
10 Maximum reservable link bandwidth 10 Maximum reservable link bandwidth
11 Unreserved bandwidth 11 Unreserved bandwidth
14 Extended Administrative Group 14 Extended Administrative Group
18 TE Default Metric 18 TE Default Metric
33 Unidirectional Link Delay 33 Unidirectional Link Delay
skipping to change at page 5, line 39 skipping to change at page 5, line 39
Supports links identified by IPv6 addresses Supports links identified by IPv6 addresses
Note that [RFC6119] prohibits the use of TLV 139 when it is possible Note that [RFC6119] prohibits the use of TLV 139 when it is possible
to use TLV 138. to use TLV 138.
4. Advertising Application Specific Link Attributes 4. Advertising Application Specific Link Attributes
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, 141, 1) Application Specific Link Attributes sub-TLV for TLVs 22, 23, 25,
222, and 223 141, 222, and 223 (defined in Section 4.2 ).
2)Application Specific Shared Risk Link Group (SRLG) TLV 2)Application Specific Shared Risk Link Group (SRLG) TLV (defined in
Section 4.3).
In support of these new advertisements, an application bit mask is In support of these new advertisements, an application identifier bit
defined which identifies the application(s) associated with a given mask is defined which identifies the application(s) associated with a
advertisement. 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-
standard User Defined Applications(UDAs). standard User Defined Applications(UDAs).
skipping to change at page 6, line 28 skipping to change at page 6, line 28
| SABML+F | 1 octet | SABML+F | 1 octet
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
| UDABML+F | 1 octet | UDABML+F | 1 octet
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
| SABM ... 0 - 127 octets | SABM ... 0 - 127 octets
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
| UDABM ... 0 - 127 octets | UDABM ... 0 - 127 octets
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
SABML+F (1 octet) SABML+F (1 octet)
Standard Application Bit Mask Length/Flags Standard Application Identifier Bit Mask
Length/Flags
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
|L| SA-Length | |L| SA-Length |
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
L-flag: Applications listed (both Standard and L-flag: When set, applications listed (both Standard
User Defined) MUST use the legacy advertisements and User Defined) MUST use the legacy advertisements
for the corresponding link found in TLVs 22, 23, for the corresponding link found in TLVs 22, 23,
141, 222, and 223 or TLV 138 or TLV 139 as appropriate. 25, 141, 222, and 223 or TLV 138 or TLV 139 as
appropriate.
SA-Length: Indicates the length in octets (0-127) of the Bit Mask SA-Length: Indicates the length in octets (0-127) of the Bit Mask
for Standard Applications. for Standard Applications.
UDABML+F (1 octet) UDABML+F (1 octet)
User Defined Application Bit Mask Length/Flags User Defined Application Identifier Bit Mask
Length/Flags
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
|R| UDA-Length | |R| UDA-Length |
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
R: Reserved. Transmitted as 0 and ignored on receipt R: Reserved. SHOULD be transmitted as 0 and
MUST be ignored on receipt
UDA-Length: Indicates the length in octets (0-127) of the Bit Mask UDA-Length: Indicates the length in octets (0-127) of the Bit Mask
for User Defined Applications. for User Defined Applications.
SABM (variable length) SABM (variable length)
Standard Application Bit Mask Standard Application Identifier Bit Mask
(SA-Length * 8) bits (SA-Length * 8) bits
This is omitted if SA-Length is 0. This is omitted if SA-Length is 0.
0 1 2 3 4 5 6 7 ... 0 1 2 3 4 5 6 7 ...
+-+-+-+-+-+-+-+-+... +-+-+-+-+-+-+-+-+...
|R|S|F|X| ... |R|S|F| ...
+-+-+-+-+-+-+-+-+... +-+-+-+-+-+-+-+-+...
R-bit: RSVP-TE R-bit: Set to specify RSVP-TE
S-bit: Segment Routing Traffic Engineering
F-bit: Loop Free Alternate S-bit: Set to specify Segment Routing
Traffic Engineering
X-bit: Flex-Algo F-bit: Set to specify Loop Free Alternate
(includes all LFA types)
UDABM (variable length) UDABM (variable length)
User Defined Application Bit Mask User Defined Application Identifier Bit Mask
(UDA Length * 8) bits (UDA-Length * 8) bits
0 1 2 3 4 5 6 7 ... 0 1 2 3 4 5 6 7 ...
+-+-+-+-+-+-+-+-+... +-+-+-+-+-+-+-+-+...
| ... | ...
+-+-+-+-+-+-+-+-+... +-+-+-+-+-+-+-+-+...
This is omitted if UDA-Length is 0. This is omitted if UDA-Length is 0.
NOTE: If both SA-length and UDA-Length are zero, then the NOTE: If both SA-length and UDA-Length are zero, then the
attributes associated with this attribute identifier bit mask attributes associated with this Attribute Identifier Bit Mask
MAY be used by any Standard Application and any User Defined MAY be used by any Standard Application and any User Defined
Application. Application.
Standard Application Bits are defined/sent starting with Bit 0. Standard Application Identifier Bits are defined/sent starting with
Additional bit definitions that may be defined in the future SHOULD Bit 0. Additional bit definitions that may be defined in the future
be assigned in ascending bit order so as to minimize the number of SHOULD be assigned in ascending bit order so as to minimize the
octets that will need to be transmitted. Undefined bits MUST be number of octets that will need to be transmitted. Undefined bits
transmitted as 0 and MUST be ignored on receipt. Bits that are NOT MUST be transmitted as 0 and MUST be ignored on receipt. Bits that
transmitted MUST be treated as if they are set to 0 on receipt. are NOT transmitted MUST be treated as if they are set to 0 on
receipt.
User Defined Application bits have no relationship to Standard User Defined Application Identifier Bits have no relationship to
Application bits and are NOT managed by IANA or any other standards Standard Application Identifier Bits and are NOT managed by IANA or
body. It is recommended that bits are used starting with Bit 0 so as any other standards body. It is recommended that bits are used
to minimize the number of octets required to advertise all UDAs. starting with Bit 0 so as to minimize the number of octets required
to advertise all UDAs.
4.2. Application Specific Link Attributes sub-TLV 4.2. Application Specific Link Attributes sub-TLV
A new sub-TLV for TLVs 22, 23, 141, 222, and 223 is defined which A new sub-TLV for TLVs 22, 23, 25, 141, 222, and 223 is defined which
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 Bit Mask (as defined in Section 3.1) Application Identifier Bit Mask
(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] and [RFC8570] existing formats defined in [RFC5305] and [RFC8570]
When the L-flag is set in the Application Identifiers, all of the When the L-flag is set in the Application Identifier Bit Mask, all of
applications specified in the bit mask MUST use the link attribute the applications specified in the bit mask MUST use the link
sub-TLV advertisements listed in Section 3.1 for the corresponding attribute sub-TLV advertisements listed in Section 3.1 for the
link. Application specific link attribute sub-sub-TLVs for the corresponding link. Link attribute sub-sub-TLVs for the
corresponding link attributes MUST NOT be advertised for the set of corresponding link attributes MUST NOT be advertised for the set of
applications specified in the Standard/User Application Bit Masks and applications specified in the Standard/User Application Identifier
all such advertisements MUST be ignored on receipt. Bit Masks and all such advertisements MUST be ignored on receipt.
Multiple sub-TLVs for the same link MAY be advertised. When multiple Multiple Application Specific Link Attribute sub-TLVs for the same
sub-TLVs for the same link are advertised, they SHOULD advertise non- link MAY be advertised. When multiple sub-TLVs for the same link are
conflicting application/attribute pairs. A conflict exists when the advertised, they SHOULD advertise non-conflicting application/
same application is associated with two different values of the same attribute pairs. A conflict exists when the same application is
link attribute for a given link. In cases where conflicting values associated with two different values of the same link attribute for a
for the same application/attribute/link are advertised all the given link. In cases where conflicting values for the same
conflicting values MUST be ignored. application/attribute/link are advertised all the conflicting values
MUST be ignored.
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.
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 which defines
the link attribute sub-sub-TLV code points. A sub-sub-TLV is defined the link attribute sub-sub-TLV code points. This document defines a
for each of the existing sub-TLVs listed in Section 3.1 except as sub-sub-TLV for each of the existing sub-TLVs listed in Section 3.1
noted below. The format of the sub-sub-TLVs matches the format of except as noted below. The format of the sub-sub-TLVs matches the
the corresponding legacy sub-TLV and IANA is requested to assign the format of the corresponding legacy sub-TLV and IANA is requested to
legacy sub-TLV identifer to the corresponding sub-sub-TLV. assign the legacy sub-TLV identifer to the corresponding sub-sub-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 Bit Mask advertisement for a given link where the Application Identifier Bit
identifies all the applications which are making use of the value for Mask identifies all the applications which are making use of the
that link. value 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 Bit Mask. This is less efficient but still valid. Application Identifier Bit Mask. This is less efficient but still
valid.
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 Unreserved Bandwidth 4.2.2. Special Considerations for Unreserved Bandwidth
Unreserved bandwidth is an attribute specific to RSVP. When Unreserved bandwidth is an attribute specific to RSVP. When
advertised using the Application Specific Link Attributes sub-TLV, advertised using the Application Specific Link Attributes sub-TLV,
bits other than the RSVP-TE(R-bit) MUST NOT be set in the Application bits other than the RSVP-TE(R-bit) MUST NOT be set in the Application
Bit Mask. If an advertisement of Unreserved Bandwidth is received Identifier Bit Mask. If an advertisement of Unreserved Bandwidth is
with bits other than the RSVP-TE bit set, the advertisement MUST be received with bits other than the RSVP-TE bit set, the advertisement
ignored. MUST be ignored.
4.3. Application Specific SRLG TLV 4.3. Application Specific SRLG TLV
A new TLV is defined to advertise application specific SRLGs for a A new TLV is defined to advertise application specific SRLGs for a
given link. Although similar in functionality to TLV 138 (defined by given link. Although similar in functionality to TLV 138 (defined by
[RFC5307]) and TLV 139 (defined by [RFC6119], a single TLV provides [RFC5307]) and TLV 139 (defined by [RFC6119], a single TLV provides
support for IPv4, IPv6, and unnumbered identifiers for a link. support for IPv4, IPv6, and unnumbered identifiers for a link.
Unlike TLVs 138/139, it utilizes sub-TLVs to encode the link Unlike TLVs 138/139, it utilizes sub-TLVs to encode the link
identifiers in order to provide the flexible formatting required to identifiers in order to provide the flexible formatting required to
support multiple link identifier types. support multiple link identifier types.
Type: 238 (Temporarily assigned by IANA) Type: 238 (Temporarily assigned by IANA)
Length: Number of octets in the value field (1 octet) Length: Number of octets in the value field (1 octet)
Value: Value:
Neighbor System-ID + pseudo-node ID (7 octets) Neighbor System-ID + pseudo-node ID (7 octets)
Application Bit Mask (as defined in Section 3.1) Application Identifier Bit Mask
(as defined in Section 4.1)
Length of sub-TLVs (1 octet) Length of sub-TLVs (1 octet)
Link Identifier sub-TLVs (variable) Link Identifier sub-TLVs (variable)
0 or more SRLG Values (Each value is 4 octets) 0 or more SRLG Values (Each value is 4 octets)
The following Link Identifier sub-TLVs are defined. The type The following Link Identifier sub-TLVs are defined. The type
values are suggested and will be assigned by IANA - but as values are suggested and will be assigned by IANA - but as
the formats are identical to existing sub-TLVs defined for the formats are identical to existing sub-TLVs defined for
TLVs 22, 23, 141, 222, and 223 the use of the suggested sub-TLV TLVs 22, 23, 25, 141, 222, and 223 the use of the suggested
types is strongly encouraged. sub-TLV types is strongly encouraged.
Type Description Type Description
4 Link Local/Remote Identifiers (see [RFC5307]) 4 Link Local/Remote Identifiers (see [RFC5307])
6 IPv4 interface address (see [RFC5305]) 6 IPv4 interface address (see [RFC5305])
8 IPv4 neighbor address (see [RFC5305]) 8 IPv4 neighbor address (see [RFC5305])
12 IPv6 Interface Address (see [RFC6119]) 12 IPv6 Interface Address (see [RFC6119])
13 IPv6 Neighbor Address (see [RFC6119]) 13 IPv6 Neighbor Address (see [RFC6119])
At least one set of link identifiers (IPv4, IPv6, or unnumbered) MUST At least one set of link identifiers (IPv4, IPv6, or unnumbered) MUST
be present. TLVs which do not meet this requirement MUST be ignored. be present. TLVs which do not meet this requirement 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 Identifiers, SRLG values When the L-flag is set in the Application Identifier Bit Mask, SRLG
MUST NOT be included in the TLV. Any SRLG values which are values MUST NOT be included in the TLV. Any SRLG values which 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 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. Deployment Considerations 5. Deployment Considerations
If link attributes are advertised associated with zero length If link attributes are advertised associated with zero length
application bit masks for both standard applications and user defined Application Identifier Bit Masks for both standard applications and
applications, then that set of link attributes MAY be used by any user defined applications, then that set of link attributes MAY be
application. If support for a new application is introduced on any used by any application. If support for a new application is
node in a network in the presence of such advertisements, these introduced on any node in a network in the presence of such
advertisements MAY be used by the new application. If this is not advertisements, these advertisements MAY be used by the new
what is intended, then existing advertisements MUST be readvertised application. If this is not what is intended, then existing
with an explicit set of applications specified before a new advertisements MUST be readvertised with an explicit set of
application is introduced. applications specified before a new application is introduced.
6. Attribute Advertisements and Enablement 6. Attribute Advertisements and Enablement
This document defines extensions to support the advertisement of This document defines extensions to support the advertisement of
application specific link attributes. application specific link attributes.
Whether the presence of link attribute advertisements for a given Whether the presence of link attribute advertisements for a given
application indicates that the application is enabled on that link application indicates that the application is enabled on that link
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
skipping to change at page 11, line 32 skipping to change at page 11, line 32
attributes does NOT indicate enablement of SRTE. The advertisements attributes does NOT indicate enablement of SRTE. The advertisements
are only used to support constraints which may be applied when are only used to support constraints which may be applied when
specifying an explicit path. SRTE is implicitly enabled on all links specifying an explicit path. SRTE is implicitly enabled on all links
which are part of the Segment Routing enabled topology independent of which are part of the Segment Routing enabled topology independent of
the existence of link attribute advertisements 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.
In the case of Flex-Algo, advertisement of application specific link
attributes does NOT indicate enablement of Flex-Algo. Rather the
attributes are used to determine what links are included/excluded in
the algorithm specific constrained SPF. This is fully specified in
[I-D.ietf-lsr-flex-algo].
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.
This document allows the advertisement of application specific link This document allows the advertisement of application specific link
attributes with no application identifiers i.e., both the Standard attributes with no application identifiers i.e., both the Standard
Application Bit Mask and the User Defined Application Bit Mask are Application Identifier Bit Mask and the User Defined Application
not present (See Section 4.1). This supports the use of the link Identifier Bit Mask are not present (See Section 4.1). This supports
attribute by any application. In the presence of an application the use of the link attribute by any application. In the presence of
where the advertisement of link attribute advertisements is used to an application where the advertisement of link attribute
infer the enablement of an application on that link (e.g., RSVP-TE), advertisements is used to infer the enablement of an application on
the absence of the application identifier leaves ambiguous whether that link (e.g., RSVP-TE), the absence of the application identifier
that application is enabled on such a link. This needs to be leaves ambiguous whether that application is enabled on such a link.
considered when making use of the "any application" encoding. This needs to be considered when making use of the "any application"
encoding.
7. Interoperability, Backwards Compatibility and Migration Concerns 7. Interoperability, Backwards Compatibility and Migration Concerns
Existing deployments of RSVP-TE utilize the legacy advertisements Existing deployments of RSVP-TE utilize the legacy advertisements
listed in Section 3. Routers which do not support the extensions listed in Section 3. Routers which do not support the extensions
defined in this document will only process legacy advertisements and defined in this document will only process legacy advertisements and
are likely to infer that RSVP-TE is enabled on the links for which are likely to infer that RSVP-TE is enabled on the links for which
legacy advertisements exist. It is expected that deployments using legacy advertisements exist. It is expected that deployments using
the legacy advertisements will persist for a significant period of the legacy advertisements will persist for a significant period of
time - therefore deployments using the extensions defined in this time - therefore deployments using the extensions defined in this
skipping to change at page 13, line 10 skipping to change at page 13, line 7
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-bit clear. In cases where specific advertisements which have the L-bit 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 The discussion in this section applies to cases where RSVP-TE is NOT
using any advertised attributes on a link and to cases where RSVP-TE using any advertised attributes on a link and to cases where RSVP-TE
is using some link attribute advertisements on the link but some link is using some link attribute advertisements on the link but some link
attributes cannot be shared with RSVP-TE. attributes cannot be shared with RSVP-TE.
7.4. Deprecating legacy advertisements 7.4. 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 - so a long term goal for deployments would be supported applications. This allows that RSVP-TE could eventually
to deprecate use of the legacy advertisements in support of RSVP-TE. utilize the application specific advertisements. This can be done in
This can be done in the following step-wise manner: the following step-wise manner:
1)Upgrade all routers to support extensions in this document 1)Upgrade all routers to support extensions in this document
2)Readvertise all legacy link attributes using application specific 2)Readvertise all legacy link attributes using application specific
advertisements with L-bit clear and R-bit set. advertisements with L-bit clear and R-bit set.
3)Remove legacy advertisements 3)Remove legacy advertisements
Migrating RSVP-TE away from legacy advertisements could result in
some implementation simplification as it allows the removal of code
which encodes/decodes the legacy advertisements. Whether this is
seen as desirable is something for the marketplace to determine.
8. IANA Considerations 8. IANA Considerations
This document defines a new sub-TLV for TLVs 22, 23, 141, 222, and This document defines a new sub-TLV for TLVs 22, 23, 25, 141, 222,
223. and 223.
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
This document defines one new TLV: This document defines one new TLV:
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
This document requests a new IANA registry be created to control the This document requests a new IANA registry be created to control the
assignment of sub-sub-TLV codepoints for the Application Specific assignment of sub-sub-TLV codepoints for the Application Specific
Link Attributes sub-TLV. The suggested name of the new registry is Link Attributes sub-TLV. The suggested name of the new registry is
"sub-sub-TLV code points for application specific link attributes". "sub-sub-TLV code points for application specific link attributes".
The registration procedure is "Expert Review" as defined in The registration procedure is "Expert Review" as defined in
[RFC8126]. The following assignments are made by this document: [RFC8126]. The following assignments are made by this document:
Type Description Type Description
skipping to change at page 14, line 29 skipping to change at page 14, line 29
34 Min/Max Unidirectional Link Delay 34 Min/Max Unidirectional Link Delay
35 Unidirectional Delay Variation 35 Unidirectional Delay Variation
36 Unidirectional Link Loss 36 Unidirectional Link Loss
37 Unidirectional Residual Bandwidth 37 Unidirectional Residual Bandwidth
38 Unidirectional Available Bandwidth 38 Unidirectional Available Bandwidth
39 Unidirectional Utilized Bandwidth 39 Unidirectional Utilized Bandwidth
40-255 Unassigned 40-255 Unassigned
This document requests a new IANA registry be created, under the This document requests a new IANA registry be created, under the
category of "Interior Gateway Protocol (IGP) Parameters", to control category of "Interior Gateway Protocol (IGP) Parameters", to control
the assignment of application bit identifiers. 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] and policy for this registry is "Standards Action" ([RFC8126] and
[RFC7120]). The following assignments are made by this document: [RFC7120]). 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 Traffic Engineering (S-bit)
2 Loop Free Alternate (F-bit) 2 Loop Free Alternate (F-bit)
3 Flex Algorithm (X-bit)
This document requests a new IANA registry be created to control the This document requests a new IANA registry be created to control the
assignment of sub-TLV types for the application specific SRLG TLV. assignment of sub-TLV types for the application specific SRLG TLV.
The suggested name of the new registry is "Sub-TLVs for TLV 238". The suggested name of the new registry is "Sub-TLVs for TLV 238".
The registration procedure is "Expert Review" as defined in The registration procedure is "Expert Review" as defined in
[RFC8126]. The following assignments are made by this document: [RFC8126]. The following assignments are made by this document:
Value Description Value Description
--------------------------------------------------------- ---------------------------------------------------------
0-3 Unassigned 0-3 Unassigned
skipping to change at page 16, line 34 skipping to change at page 16, line 34
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>. May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8570] Ginsberg, L., Ed., Previdi, S., Ed., Giacalone, S., Ward, [RFC8570] Ginsberg, L., Ed., Previdi, S., Ed., Giacalone, S., Ward,
D., Drake, J., and Q. Wu, "IS-IS Traffic Engineering (TE) D., Drake, J., and Q. Wu, "IS-IS Traffic Engineering (TE)
Metric Extensions", RFC 8570, DOI 10.17487/RFC8570, March Metric Extensions", RFC 8570, DOI 10.17487/RFC8570, March
2019, <https://www.rfc-editor.org/info/rfc8570>. 2019, <https://www.rfc-editor.org/info/rfc8570>.
11.2. Informative References 11.2. Informative References
[I-D.ietf-lsr-flex-algo]
Psenak, P., Hegde, S., Filsfils, C., Talaulikar, K., and
A. Gulko, "IGP Flexible Algorithm", draft-ietf-lsr-flex-
algo-01 (work in progress), November 2018.
[I-D.ietf-spring-segment-routing-policy] [I-D.ietf-spring-segment-routing-policy]
Filsfils, C., Sivabalan, S., daniel.voyer@bell.ca, d., Filsfils, C., Sivabalan, S., daniel.voyer@bell.ca, d.,
bogdanov@google.com, b., and P. Mattes, "Segment Routing bogdanov@google.com, b., and P. Mattes, "Segment Routing
Policy Architecture", draft-ietf-spring-segment-routing- Policy Architecture", draft-ietf-spring-segment-routing-
policy-02 (work in progress), October 2018. policy-03 (work in progress), May 2019.
[RFC7855] Previdi, S., Ed., Filsfils, C., Ed., Decraene, B., [RFC7855] Previdi, S., Ed., Filsfils, C., Ed., Decraene, B.,
Litkowski, S., Horneffer, M., and R. Shakir, "Source Litkowski, S., Horneffer, M., and R. Shakir, "Source
Packet Routing in Networking (SPRING) Problem Statement Packet Routing in Networking (SPRING) Problem Statement
and Requirements", RFC 7855, DOI 10.17487/RFC7855, May and Requirements", RFC 7855, DOI 10.17487/RFC7855, May
2016, <https://www.rfc-editor.org/info/rfc7855>. 2016, <https://www.rfc-editor.org/info/rfc7855>.
Authors' Addresses Authors' Addresses
Les Ginsberg Les Ginsberg
Cisco Systems Cisco Systems
821 Alder Drive 821 Alder Drive
Milpitas, CA 95035 Milpitas, CA 95035
USA USA
Email: ginsberg@cisco.com Email: ginsberg@cisco.com
Peter Psenak Peter Psenak
Cisco Systems Cisco Systems
 End of changes. 53 change blocks. 
120 lines changed or deleted 128 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/