Internet DRAFT - draft-aravindbabu-idr-bgp-ls-flex-algo-ext
draft-aravindbabu-idr-bgp-ls-flex-algo-ext
Inter-Domain Routing K. Talaulikar
Internet-Draft A. MahendraBabu
Intended status: Standards Track Cisco Systems
Expires: 10 September 2023 9 March 2023
Advertising Flexible Algorithm Extensions in BGP Link-State
draft-aravindbabu-idr-bgp-ls-flex-algo-ext-00
Abstract
Flexible Algorithm is a solution that allows some routing protocols
(e.g., OSPF and IS-IS) to compute paths over a network based on user-
defined (and hence, flexible) constraints and metrics. The
computation is performed by routers participating in the specific
network in a distributed manner using a Flexible Algorithm
Definition. This Definition is provisioned on one or more routers
and propagated through the network by OSPF and IS-IS flooding.
BGP Link-State (BGP-LS) enables the collection of various topology
information from the network. RFC9351 introduced BGP-LS support for
the advertisement of Flexible Algorithm Definition as a part of the
topology information from the network. This document specifies the
advertisement of further Flexible Algorithm related extensions in
BGP-LS.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
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Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on 10 September 2023.
Copyright Notice
Copyright (c) 2023 IETF Trust and the persons identified as the
document authors. All rights reserved.
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This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents (https://trustee.ietf.org/
license-info) in effect on the date of publication of this document.
Please review these documents carefully, as they describe your rights
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3
2. Advertising IP Algorithm Participation . . . . . . . . . . . 3
3. Advertising IP Algorithm Reachability . . . . . . . . . . . . 4
4. Advertising Generic Metric for Links . . . . . . . . . . . . 6
5. Advertising Flexible Algorithm Definition Extensions . . . . 7
5.1. FAD Exclude Minimum Bandwidth Sub-TLV . . . . . . . . . . 7
5.2. FAD Exclude Maximum Link Delay Sub-TLV . . . . . . . . . 8
5.3. FAD Reference Bandwidth Sub-TLV . . . . . . . . . . . . . 8
5.4. FAD Bandwidth Thresholds Sub-TLV . . . . . . . . . . . . 9
5.5. Flexible Algorithm Exclude-Any Reverse Affinity
Sub-TLV . . . . . . . . . . . . . . . . . . . . . . . . . 11
5.6. Flexible Algorithm Include-Any Reverse Affinity
Sub-TLV . . . . . . . . . . . . . . . . . . . . . . . . . 12
5.7. Flexible Algorithm Include-All Reverse Affinity
Sub-TLV . . . . . . . . . . . . . . . . . . . . . . . . . 12
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13
7. Manageability Considerations . . . . . . . . . . . . . . . . 14
8. Security Considerations . . . . . . . . . . . . . . . . . . . 14
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 14
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 14
10.1. Normative References . . . . . . . . . . . . . . . . . . 14
10.2. Informative References . . . . . . . . . . . . . . . . . 15
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 16
1. Introduction
Flexible Algorithm is a solution that allows some routing protocols
(e.g., OSPF and IS-IS) to compute paths over a network based on user-
defined (and hence, flexible) constraints and metrics. The
computation is performed by routers participating in the specific
network in a distributed manner using a Flexible Algorithm
Definition. This Definition is provisioned on one or more routers
and propagated through the network by OSPF and IS-IS flooding.
[RFC9350] defines the base Flexible Algorithm solution that allows
IGPs themselves to compute constraint-based paths over the network.
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The extensions to BGP-LS [RFC7752] for the advertisement of the
Flexible Algorithm Definition (FAD) information to enable learning of
the mapping of the flexible algorithm number to its Definition in
each area/domain of the underlying IGPs are defined in [RFC9351].
This document defines further extensions to BGP-LS for Flexible
Algorithm as below:
* The extensions to the Flexible Algorithm so that it can be used
with the regular IPv4 and IPv6 forwarding as defined for IGPs in
[I-D.ietf-lsr-ip-flexalgo].
* The Flexible Algorithm Definition that is used to exclude based on
bandwidth and metric constraints and to automatically calculate
metrics for use in SPF calculation as defined for IGPs in
[I-D.ietf-lsr-flex-algo-bw-con].
* The Flexible Algorithm Definition that is used to include/exclude
links in the reverse direction of the traffic flow for SPF
calculation as defined for IGPs in
[I-D.ppsenak-lsr-igp-flex-algo-reverse-affinity].
1.1. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
2. Advertising IP Algorithm Participation
The IP Algorithm TLV is a BGP-LS Attribute TLV associated with the
Node NLRI that is used for the algorithms associated with a given
node. The format of this TLV is as follows:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Algorithm 1 | Algorithm ... | Algorithm n | //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
where:
Figure 1: IP Algorithm TLV
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* Type: TBA
* Length: Variable
* Algorithm: Single octet algorithm value between 128 and 255
inclusive.
The IP Algorithm TLV is derived from the following IGP protocol-
specific advertisements:
* In the case of IS-IS, from the IS-IS IP Algorithm sub-TLV defined
in [I-D.ietf-lsr-ip-flexalgo].
* In the case of OSPFv2/OSPFv3, from the OSPF IP Algorithm sub-TLV
defined in [I-D.ietf-lsr-ip-flexalgo].
The IP Algorithm TLV is optional and it MUST NOT be advertised more
than once in the BGP-LS Attribute. If multiple instances are
present, then the first one MUST be considered valid, and the rest
MUST be ignored.
3. Advertising IP Algorithm Reachability
The normal or base (i.e., algorithm 0) prefix reachabilities are done
using the BGP-LS IPv4/IPv6 Topology Prefix NLRIs defined in [RFC7752]
along with its associated IGP metric carried within the IGP Metric
TLV (TLV 1095) in the BGP-LS Attributed associated with the NLRI.
The presence of IGP Metric TLV is what identifies the base/normal
prefix reachability.
The IP algorithm-specific reachability advertisements are also done
using the BGP-LS IPv4/IPv6 Topology Prefix NLRIs. However, these
algorithm-specific advertisements MUST NOT carry an IGP Metric TLV
along with them. Instead, the metric associated with the IP
algorithm-specific prefix reachability is carried within the TLVs
introduced in the following subsections.
A BGP-LS Consumer receiving an IPv4/IPv6 Topology Prefix NLRI
advertisement that carries both an IGP Metric TLV along with any of
the TLVs introduced in the following subsections, MUST consider it as
a normal (i.e., algorithm 0) prefix reachability advertisement and
MUST ignore all TLVs corresponding to algorithm-specific prefix
reachability advertisements.
The IP Algorithm Prefix Reachability TLV is a BGP-LS Attribute TLV
associated with the IPv4/IPv6 Topology Prefix NLRI that is used for
the advertisement of the algorithm-specific prefix reachability from
a given node. The format of this TLV is as follows:
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags | Algorithm | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Metric |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
where:
Figure 2: IP Algorithm Prefix Reachability TLV
* Type: TBA
* Length: 8
* Flags: 1 octet of flags. The flags are copied from the IS-IS
IPv4/IPv6 Algorithm Prefix Reachability TLV
[I-D.ietf-lsr-ip-flexalgo] or the OSPFv2/OSPFv3 IP Algorithm
Prefix Reachability sub-TLV [I-D.ietf-lsr-ip-flexalgo] in the case
of IS-IS or OSPFv2/OSPFv3 respectively.
* Algorithm: 1 octet value providing the Associated Algorithm from
128 to 255.
* Reserved: 2 octet value that MUST be set to 0 by the originator
and ignored by the receiver.
* Metric: The algorithm-specific metric value.
The IP Algorithm Prefix Reachability TLV is derived from the
following IGP protocol-specific advertisements:
* In the case of IS-IS, from the IS-IS IPv4/IPv6 Algorithm Prefix
Reachability TLV defined in [I-D.ietf-lsr-ip-flexalgo]. The sub-
TLVs are encoded using the BGP-LS Attribute TLVs defined for the
IPv4/IPv6 Topology Prefix NLRI.
* In the case of OSPF, from the OSPFv2/OSPFv3 IP Algorithm Prefix
Reachability sub-TLV defined in [I-D.ietf-lsr-ip-flexalgo].
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The Multi-topology ID (MTID) associated with the underlying IGP
advertisements is encoded using the Multi-Topology Identifier TLV
(TLV 263) [RFC7752] as a Prefix Descriptor TLV when the advertisement
is associated with a non-default topology. The IP Prefix value
itself is encoded using the IP Reachability Information TLV (TLV 265)
[RFC7752] as a Prefix Descriptor TLV.
The IP Algorithm Prefix Reachability TLV MUST NOT be advertised more
than once in the BGP-LS Attribute. If multiple instances are
present, then the first one MUST be considered valid, and the rest
MUST be ignored.
4. Advertising Generic Metric for Links
The Generic Metric TLV is a BGP-LS Attribute TLV associated with the
Link NLRI that is used for the advertisement of the generic metric(s)
associated with a link. The format of this TLV is as follows:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Metric Type | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Metric |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
where:
Figure 3: Generic Metric TLV
* Type: TBA
* Length: 8.
* Metric Type: 1 octet that carries a metric type from the IGP
Metric Type registry
* Reserved: 3 octet value that MUST be set to 0 by the originator
and ignored by the receiver.
* Metric: 4-octet field carrying the metric value. In the case of
IS-IS, the value MUST be in the range of 0 - 16,777,215.
The Generic Metric TLV is derived from the following IGP protocol-
specific advertisements:
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* In the case of IS-IS, from the IS-IS Generic Metric sub-TLV
defined in [I-D.ietf-lsr-flex-algo-bw-con].
* In the case of OSPF, from the OSPF Generic Metric sub-TLV defined
in [I-D.ietf-lsr-flex-algo-bw-con].
The Generic Metric TLV MAY be advertised more than once in the BGP-LS
Attribute, one for each metric type. If multiple instances are
present for the same metric type, then the first one MUST be
considered valid, and the rest MUST be ignored.
5. Advertising Flexible Algorithm Definition Extensions
[RFC9351] introduced the Flexible Algorithm Definition (FAD) TLV that
is advertised in the BGP-LS Attribute along with the Node NLRI for
the advertisement of the Flexible Algorithm definition advertised by
a given node in IGPs.
The following subsections define new sub-TLVs of the FAD TLV to cover
further extensions of the IGP Flexible Algorithm solution.
5.1. FAD Exclude Minimum Bandwidth Sub-TLV
The FAD Exclude Minimum Bandwidth sub-TLV is an optional sub-TLV that
is used to carry the minimum bandwidth associated with the FAD that
are used in the computation of the specific algorithm as described in
[I-D.ietf-lsr-flex-algo-bw-con].
The sub-TLV has the following format:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Minimum Bandwidth |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
where:
Figure 4: FAD Exclude Minimum Bandwidth sub-TLV
* Type: TBA
* Length: 4 octets.
* Min Bandwidth: The minimum link bandwidth is encoded in 32 bits in
IEEE floating point format. The units are bytes per second.
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The information in the FAD Exclude Minimum Bandwidth sub-TLV is
derived from the IS-IS and OSPF protocol-specific FAD Exclude Minimum
Bandwidth sub-TLVs as defined in [I-D.ietf-lsr-flex-algo-bw-con].
5.2. FAD Exclude Maximum Link Delay Sub-TLV
The FAD Exclude Maximum Link Delay sub-TLV is an optional sub-TLV
that is used to carry the maximum link delay information associated
with the FAD that is used in the computation of the specific
algorithm as described in [I-D.ietf-lsr-flex-algo-bw-con].
The sub-TLV has the following format:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Maximum Link Delay | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
where:
Figure 5: FAD Exclude Maximum Link Delay sub-TLV
* Type: TBA
* Length: 4 octets.
* Maximum Link Delay: The maximum link delay is encoded in
microseconds.
* Reserved: 1 octet field that MUST be set to 0 by the originator
and ignored by the receiver.
The information in the FAD Exclude Maximum Link Delay sub-TLV is
derived from the IS-IS and OSPF protocol-specific FAD Exclude Maximum
Link Delay sub-TLVs as defined in [I-D.ietf-lsr-flex-algo-bw-con].
5.3. FAD Reference Bandwidth Sub-TLV
The FAD Reference Bandwidth sub-TLV is an optional sub-TLV that is
used to carry the information needed for the reference bandwidth
method of metric calculation associated with the FAD that is used in
the computation of the specific algorithm as described in
[I-D.ietf-lsr-flex-algo-bw-con].
The sub-TLV has the following format:
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reference Bandwidth |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Granularity Bandwidth |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
where:
Figure 6: FAD Reference Bandwidth sub-TLV
* Type: TBA
* Length: 12 octets.
* Flags: 1 octet of flags. The flags are copied from the IS-IS FAD
Reference Bandwidth sub-TLV [I-D.ietf-lsr-flex-algo-bw-con] or the
OSPF FAD Reference Bandwidth sub-TLV
[I-D.ietf-lsr-flex-algo-bw-con] in the case of IS-IS or OSPF
respectively.
* Reserved: 3 octet field that MUST be set to 0 by the originator
and ignored by the receiver.
* Reference Bandwidth: The reference bandwidth is encoded in 32 bits
in IEEE floating point format. The units are bytes per second.
* Granularity Bandwidth: The granularity bandwidth is encoded in 32
bits in IEEE floating point format. The units are bytes per
second.
The information in the FAD Reference Bandwidth sub-TLV is derived
from the IS-IS and OSPF protocol-specific FAD Reference Bandwidth
sub-TLV as defined in [I-D.ietf-lsr-flex-algo-bw-con].
5.4. FAD Bandwidth Thresholds Sub-TLV
The FAD Bandwidth Thresholds sub-TLV is an optional sub-TLV that is
used to carry the information needed for bandwidth threshold method
of metric calculation associated with the FAD that are used in the
computation of the specific algorithm as described in
[I-D.ietf-lsr-flex-algo-bw-con].
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The sub-TLV has the following format:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Bandwidth Threshold 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Threshold Metric 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Bandwidth Threshold 2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Threshold Metric 2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
...................
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Bandwidth Threshold n |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Threshold Metric n |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
where:
Figure 7: FAD Bandwidth Thresholds sub-TLV
* Type: TBA
* Length: 4 + (n * 8) octets. Here n is equal to the number of
Threshold Metrics specified. n MUST be greater than or equal to 1.
* Flags: 1 octet of flags. The flags are copied from the IS-IS FAD
Bandwidth Thresholds sub-TLV [I-D.ietf-lsr-flex-algo-bw-con] or
the OSPF FAD Bandwidth Thresholds sub-TLV
[I-D.ietf-lsr-flex-algo-bw-con] in the case of IS-IS or OSPF
respectively.
* Reserved: 3 octet field that MUST be set to 0 by the originator
and ignored by the receiver.
* Bandwidth Threshold (1 ... n): The bandwidth threshold is encoded
in 32 bits in IEEE floating point format. The units are bytes per
second.
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* Threshold Metric (1 ... n): 4 octet field carrying the threshold
metric value. In the case of IS-IS, the value MUST be in the
range of 0 - 16,777,215.
The information in the FAD Bandwidth Thresholds sub-TLV is derived
from the IS-IS and OSPF protocol-specific FAD Bandwidth Thresholds
sub-TLV as defined in [I-D.ietf-lsr-flex-algo-bw-con].
5.5. Flexible Algorithm Exclude-Any Reverse Affinity Sub-TLV
The Flexible Algorithm Exclude-Any Reverse Affinity sub-TLV is an
optional sub-TLV that is used to carry the reverse affinity
constraints associated with the FAD and enable the exclusion of links
carrying any of the specified affinities from the computation of the
specific algorithm as described in
[I-D.ppsenak-lsr-igp-flex-algo-reverse-affinity]. The affinity is
expressed in terms of Extended Admin Group (EAG) as defined in
[RFC7308].
The sub-TLV has the following format:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Exclude-Any Reverse EAG (variable) //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
where:
Figure 8: Flexible Algorithm Exclude-Any Reverse Affinity sub-TLV
* Type: TBA
* Length: The total length of the value field in octets dependent on
the size of the EAG. It MUST be a non-zero value and a multiple
of 4.
* Exclude-Any Reverse EAG: the EAG value.
The information in the Flexible Algorithm Exclude Any Reverse
Affinity sub-TLV is derived from the IS-IS and OSPF protocol-specific
Flexible Algorithm Exclude Admin Group sub-TLV as defined in
[I-D.ppsenak-lsr-igp-flex-algo-reverse-affinity].
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5.6. Flexible Algorithm Include-Any Reverse Affinity Sub-TLV
The Flexible Algorithm Include-Any Reverse Affinity sub-TLV is an
optional sub-TLV that is used to carry the affinity constraints
associated with the FAD and enable the inclusion of links carrying
any of the specified affinities in the computation of the specific
algorithm as described in
[I-D.ppsenak-lsr-igp-flex-algo-reverse-affinity]. The affinity is
expressed in terms of Extended Admin Group (EAG) as defined in
[RFC7308].
The sub-TLV has the following format:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Include-Any Reverse EAG (variable) //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
where:
Figure 9: Flexible Algorithm Include-Any Reverse Affinity sub-TLV
* Type: TBA
* Length: The total length of the value field in octets dependent on
the size of the EAG. It MUST be a non-zero value and a multiple
of 4.
* Include-Any EAG: the EAG value.
The information in the Flexible Algorithm Include-Any Reverse
Affinity sub-TLV is derived from the IS-IS and OSPF protocol-specific
Flexible Algorithm Include-Any Reverse Admin Group sub-TLV as defined
in [I-D.ppsenak-lsr-igp-flex-algo-reverse-affinity].
5.7. Flexible Algorithm Include-All Reverse Affinity Sub-TLV
The Flexible Algorithm Include-All Reverse Affinity sub-TLV is an
optional sub-TLV that is used to carry the affinity constraints
associated with the FAD and enable the inclusion of links carrying
all of the specified affinities in the computation of the specific
algorithm as described in
[I-D.ppsenak-lsr-igp-flex-algo-reverse-affinity]. The affinity is
expressed in terms of Extended Admin Group (EAG) as defined in
[RFC7308].
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The sub-TLV has the following format:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Include-All Reverse EAG (variable) //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
where:
Figure 10: Flexible Algorithm Include-All Reverse Affinity sub-TLV
* Type: TBA
* Length: The total length of the value field in octets dependent on
the size of the EAG. It MUST be a non-zero value and a multiple
of 4.
* Include-All EAG: the EAG value.
The information in the Flexible Algorithm Include-All Reverse
Affinity sub-TLV is derived from the IS-IS and OSPF protocol-specific
Flexible Algorithm Include-All Reverse Admin Group sub-TLV as defined
in [I-D.ppsenak-lsr-igp-flex-algo-reverse-affinity].
6. IANA Considerations
This document requests IANA to allocate code points from the "BGP-LS
NLRI and Attribute TLVs" sub-registry of the "Border Gateway Protocol
- Link-State (BGP-LS) Parameters" registry group.
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+-------+------------------------------------------+---------------+
| Code | | |
| Point | Description | Reference |
+-------+------------------------------------------+---------------+
| TBA | IP Algorithm | this document |
| TBA | IP Algorithm Prefix Reachability | this document |
| TBA | Generic Metric | this document |
| TBA | Flexible Algorithm Exclude | this document |
| | Minimum Bandwidth | |
| TBA | Flexible Algorithm Exclude | this document |
| | Maximum Link Delay | |
| TBA | Flexible Algorithm Reference Bandwidth | this document |
| TBA | Flexible Algorithm Bandwidth Thresholds | this document |
| TBA | Flexible Algorithm Exclude Any Reverse | this document |
| | Affinity | |
| TBA | Flexible Algorithm Include Any Reverse | this document |
| | Affinity | |
| TBA | Flexible Algorithm Include All Reverse | this document |
| | Affinity | |
+-------+------------------------------------------+---------------+
Figure 11: BGP-LS Flexible Algorithm Extensions Code Points
7. Manageability Considerations
This document does not introduce any new manageability considerations
beyond those covered by [RFC9351].
8. Security Considerations
This document does not introduce any new security considerations
beyond those covered by [RFC9351].
9. Acknowledgements
10. References
10.1. Normative References
[I-D.ietf-lsr-flex-algo-bw-con]
Hegde, S., Britto, W., Shetty, R., Decraene, B., Psenak,
P., and T. Li, "Flexible Algorithms: Bandwidth, Delay,
Metrics and Constraints", Work in Progress, Internet-
Draft, draft-ietf-lsr-flex-algo-bw-con-05, 16 January
2023, <https://datatracker.ietf.org/doc/html/draft-ietf-
lsr-flex-algo-bw-con-05>.
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[I-D.ietf-lsr-ip-flexalgo]
Britto, W., Hegde, S., Kaneriya, P., Shetty, R., Bonica,
R., and P. Psenak, "IGP Flexible Algorithms (Flex-
Algorithm) In IP Networks", Work in Progress, Internet-
Draft, draft-ietf-lsr-ip-flexalgo-08, 19 December 2022,
<https://datatracker.ietf.org/doc/html/draft-ietf-lsr-ip-
flexalgo-08>.
[I-D.ppsenak-lsr-igp-flex-algo-reverse-affinity]
Psenak, P., Horn, J., and A. Dhamija, "IGP Flexible
Algorithms Reverse Affinity Constraint", Work in Progress,
Internet-Draft, draft-ppsenak-lsr-igp-flex-algo-reverse-
affinity-01, 4 January 2023,
<https://datatracker.ietf.org/doc/html/draft-ppsenak-lsr-
igp-flex-algo-reverse-affinity-01>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC7752] Gredler, H., Ed., Medved, J., Previdi, S., Farrel, A., and
S. Ray, "North-Bound Distribution of Link-State and
Traffic Engineering (TE) Information Using BGP", RFC 7752,
DOI 10.17487/RFC7752, March 2016,
<https://www.rfc-editor.org/info/rfc7752>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC9350] Psenak, P., Ed., Hegde, S., Filsfils, C., Talaulikar, K.,
and A. Gulko, "IGP Flexible Algorithm", RFC 9350,
DOI 10.17487/RFC9350, February 2023,
<https://www.rfc-editor.org/info/rfc9350>.
[RFC9351] Talaulikar, K., Ed., Psenak, P., Zandi, S., and G. Dawra,
"Border Gateway Protocol - Link State (BGP-LS) Extensions
for Flexible Algorithm Advertisement", RFC 9351,
DOI 10.17487/RFC9351, February 2023,
<https://www.rfc-editor.org/info/rfc9351>.
10.2. Informative References
[RFC7308] Osborne, E., "Extended Administrative Groups in MPLS
Traffic Engineering (MPLS-TE)", RFC 7308,
DOI 10.17487/RFC7308, July 2014,
<https://www.rfc-editor.org/info/rfc7308>.
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Authors' Addresses
Ketan Talaulikar
Cisco Systems
India
Email: ketant.ietf@gmail.com
Aravind Babu MahendraBabu
Cisco Systems
India
Email: aravindbabu.mahendrababu@gmail.com
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