rfc9816v1.txt   rfc9816.txt 
Internet Engineering Task Force (IETF) K. Patel Internet Engineering Task Force (IETF) K. Patel
Request for Comments: 9816 Arrcus, Inc. Request for Comments: 9816 A. Lindem
Category: Informational A. Lindem Category: Informational Arrcus, Inc.
ISSN: 2070-1721 LabN Consulting, L.L.C. ISSN: 2070-1721 S. Zandi
S. Zandi
LinkedIn
G. Dawra G. Dawra
Linkedin Google
J. Dong J. Dong
Huawei Technologies Huawei Technologies
July 2025 July 2025
Usage and Applicability of BGP Link-State Shortest Path Routing (BGP- Usage and Applicability of BGP Link State (BGP-LS) Shortest Path First
SPF) in Data Centers (SPF) Routing in Data Centers
Abstract Abstract
This document discusses the usage and applicability of BGP Link-State This document discusses the usage and applicability of BGP Link State
Shortest Path First (BGP-SPF) extensions in data center networks (BGP-LS) Shortest Path First (SPF) extensions in data center networks
utilizing Clos or Fat Tree topologies. The document is intended to utilizing Clos or Fat Tree topologies. The document is intended to
provide simplified guidance for the deployment of BGP-SPF extensions. provide simplified guidance for the deployment of BGP-LS SPF
extensions.
Status of This Memo Status of This Memo
This document is not an Internet Standards Track specification; it is This document is not an Internet Standards Track specification; it is
published for informational purposes. published for informational purposes.
This document is a product of the Internet Engineering Task Force This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has (IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Not all documents Internet Engineering Steering Group (IESG). Not all documents
skipping to change at line 71 skipping to change at line 71
5. BGP-SPF Applicability to Clos Networks 5. BGP-SPF Applicability to Clos Networks
5.1. Usage of BGP-LS-SPF SAFI 5.1. Usage of BGP-LS-SPF SAFI
5.1.1. Relationship to Other BGP AFI/SAFI Tuples 5.1.1. Relationship to Other BGP AFI/SAFI Tuples
5.2. Peering Models 5.2. Peering Models
5.2.1. Sparse Peering Model 5.2.1. Sparse Peering Model
5.2.2. Biconnected Graph Heuristic 5.2.2. Biconnected Graph Heuristic
5.3. BGP Spine/Leaf Topology Policy 5.3. BGP Spine/Leaf Topology Policy
5.4. BGP Peer Discovery Considerations 5.4. BGP Peer Discovery Considerations
5.5. BGP Peer Discovery 5.5. BGP Peer Discovery
5.5.1. BGP IPv6 Simplified Peering 5.5.1. BGP IPv6 Simplified Peering
5.5.2. BGP-LS SPF Topology Visibility for Management 5.5.2. BGP-LS-SPF Topology Visibility for Management
5.5.3. Data Center Interconnect (DCI) Applicability 5.5.3. Data Center Interconnect (DCI) Applicability
6. Non-Clos / Fat Tree Topology Applicability 6. Non-Clos / Fat Tree Topology Applicability
7. Non-Transit Node Capability 7. Non-Transit Node Capability
8. BGP Policy Applicability 8. BGP Policy Applicability
9. IANA Considerations 9. IANA Considerations
10. Security Considerations 10. Security Considerations
11. References 11. References
11.1. Normative References 11.1. Normative References
11.2. Informative References 11.2. Informative References
Acknowledgements Acknowledgements
Authors' Addresses Authors' Addresses
1. Introduction 1. Introduction
This document complements [RFC9815] by discussing the applicability This document complements [RFC9815] by discussing the applicability
of the BGP-SPF technology in a simple and fairly common deployment of the BGP Link State (BGP-LS) Shortest Path First (SPF) technology
scenario, which is described in Section 3. in a simple and fairly common deployment scenario, which is described
in Section 3.
Section 4 describes the reasons for BGP modifications for such Section 4 describes the reasons for BGP modifications for such
deployments. deployments.
Section 5 covers the BGP-SPF protocol enhancements to BGP to meet Section 5 covers the BGP SPF protocol enhancements to BGP to meet
these requirements and their applicability to data center [Clos] these requirements and their applicability to data center [Clos]
networks. networks.
2. Recommended Reading 2. Recommended Reading
This document assumes knowledge of existing data center networks and This document assumes knowledge of existing data center networks and
data center network topologies [Clos]. This document also assumes data center network topologies [Clos]. This document also assumes
knowledge of data center routing protocols such as BGP [RFC4271], knowledge of data center routing protocols such as BGP [RFC4271],
BGP-SPF [RFC9815], and OSPF [RFC2328] [RFC5340] as well as data BGP-LS SPF [RFC9815], and OSPF [RFC2328] [RFC5340] as well as data
center Operations, Administration, and Maintenance (OAM) protocols center Operations, Administration, and Maintenance (OAM) protocols
like the Link Layer Discovery Protocol (LLDP) [RFC4957] and like the Link Layer Discovery Protocol (LLDP) [RFC4957] and
Bidirectional Forwarding Detection (BFD) [RFC5880]. Bidirectional Forwarding Detection (BFD) [RFC5880].
3. Common Deployment Scenario 3. Common Deployment Scenario
Within a data center, servers are commonly interconnected using the Within a data center, servers are commonly interconnected using the
Clos topology [Clos]. The Clos topology is fully non-blocking, and Clos topology [Clos]. The Clos topology is fully non-blocking, and
the topology is realized using Equal-Cost Multipath (ECMP). In a the topology is realized using Equal-Cost Multipath (ECMP). In a
multi-stage Clos topology, the minimum number of parallel paths in multi-stage Clos topology, the minimum number of parallel paths in
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resolve any overlay next hops. The hop-by-hop BGP peering paradigm resolve any overlay next hops. The hop-by-hop BGP peering paradigm
imposes several restrictions within a Clos. It prohibits the imposes several restrictions within a Clos. It prohibits the
deployment of route reflectors / route controllers as the EBGP deployment of route reflectors / route controllers as the EBGP
sessions are congruent with the data path. The BGP best-path sessions are congruent with the data path. The BGP best-path
algorithm is prefix based, and it prevents announcements of prefixes algorithm is prefix based, and it prevents announcements of prefixes
to other BGP speakers until the best-path decision process has been to other BGP speakers until the best-path decision process has been
performed for the prefix at each intermediate hop. These performed for the prefix at each intermediate hop. These
restrictions significantly delay the overall convergence of the restrictions significantly delay the overall convergence of the
underlay network within a Clos network. underlay network within a Clos network.
The BGP-SPF modifications allow BGP to overcome these limitations. The BGP SPF modifications allow BGP to overcome these limitations.
Furthermore, using the BGP-LS Network Layer Reachability Information Furthermore, using the BGP-LS Network Layer Reachability Information
(NLRI) format allows the BGP-SPF data to be advertised for nodes, (NLRI) format allows the BGP SPF data to be advertised for nodes,
links, and prefixes in the BGP routing domain and used for SPF links, and prefixes in the BGP routing domain [RFC9552] and used for
computations [RFC9552]. SPF computations [RFC9815].
Additional motivation for deploying BGP-SPF is included in [RFC9815]. Additional motivation for deploying BGP-SPF is included in [RFC9815].
5. BGP-SPF Applicability to Clos Networks 5. BGP-SPF Applicability to Clos Networks
With the BGP-SPF extensions [RFC9815], the BGP best-path computation With the BGP-SPF extensions [RFC9815], the BGP best-path computation
and route computation are replaced with link-state algorithms such as and route computation are replaced with link-state algorithms such as
those used by OSPF [RFC2328], both to determine whether a BGP-LS-SPF those used by OSPF [RFC2328], both to determine whether a BGP-LS-SPF
NLRI has changed and needs to be readvertised and to compute the BGP NLRI has changed and needs to be readvertised and to compute the BGP
routes. These modifications will significantly improve convergence routes. These modifications will significantly improve convergence
of the underlay while affording the operational benefits of a single of the underlay while affording the operational benefits of a single
routing protocol [RFC7938]. routing protocol [RFC7938].
Data center controllers typically require visibility to the BGP Data center controllers typically require visibility to the BGP
topology to compute traffic-engineered paths. These controllers topology to compute traffic-engineered paths. These controllers
learn the topology and other relevant information via the BGP-LS learn the topology and other relevant information via the BGP-LS
address family [RFC9552], which is totally independent of the address family [RFC9552], which is totally independent of the
underlay address families (usually IPv4/IPv6 unicast). Furthermore, underlay address families (usually IPv4/IPv6 unicast). Furthermore,
in traditional BGP underlays, all the BGP routers will need to in usual BGP underlays, all the BGP routers will need to advertise
advertise their BGP-LS information independently. With the BGP-SPF their BGP-LS information independently. With the BGP-SPF extensions,
extensions, controllers can learn the topology using the same BGP controllers can learn the topology using the same BGP advertisements
advertisements used to compute the underlay routes. Furthermore, used to compute the underlay routes. Furthermore, these data center
these data center controllers can avail the convergence advantages of controllers can avail the convergence advantages of the BGP-SPF
the BGP-SPF extensions. The placement of controllers can be outside extensions. The placement of controllers can be outside of the
of the forwarding path or within the forwarding path. forwarding path or within the forwarding path.
Alternatively, as each and every router in the BGP-SPF domain will Alternatively, as each and every router in the BGP-SPF domain will
have a complete view of the topology, the operator can also choose to have a complete view of the topology, the operator can also choose to
configure BGP sessions in the hop-by-hop peering model described in configure BGP sessions in the hop-by-hop peering model described in
[RFC7938] along with BFD [RFC5580]. In doing so, while the hop-by- [RFC7938] along with BFD [RFC5880]. In doing so, while the hop-by-
hop peering model lacks the inherent benefits of the controller-based hop peering model lacks the inherent benefits of the controller-based
model, BGP updates need not be serialized by the BGP best-path model, BGP updates need not be serialized by the BGP best-path
algorithm in either of these models. This helps overall network algorithm in either of these models. This helps overall network
convergence. convergence.
5.1. Usage of BGP-LS-SPF SAFI 5.1. Usage of BGP-LS-SPF SAFI
Section 5.1 of [RFC9815] defines a new BGP-LS-SPF SAFI for Section 5.1 of [RFC9815] defines a new BGP-LS-SPF SAFI for
announcement of the BGP-SPF link-state. The NLRI format and its announcement of the BGP-SPF link-state. The NLRI format and its
associated attributes follow the format of BGP-LS for node, link, and associated attributes follow the format of BGP-LS for node, link, and
prefix announcements. Whether the peering model within a Clos prefix announcements. Whether the peering model within a Clos
follows hop-by-hop peering described in [RFC7938] or any controller- follows hop-by-hop peering as described in [RFC7938] or any
based or route-reflector peering, an operator can exchange BGP-LS-SPF controller-based or route-reflector peering, an operator can exchange
SAFI routes over the BGP peering by simply configuring BGP-LS-SPF BGP-LS-SPF SAFI routes over the BGP peering by simply configuring
SAFI between the necessary BGP speakers. BGP-LS-SPF SAFI between the necessary BGP speakers.
The BGP-LS-SPF SAFI can also coexist with BGP IP Unicast SAFI The BGP-LS-SPF SAFI can also coexist with BGP IP Unicast SAFI
[RFC4760], which could exchange overlapping IP routes. One use case [RFC4760], which could exchange overlapping IP routes. One use case
for this is where BGP-LS-SPF routes are used for the underlay and BGP for this is where BGP-LS-SPF routes are used for the underlay and BGP
IP Unicast routes for VPNs are advertised in the overlay as described IP Unicast routes for VPNs are advertised in the overlay as described
in [RFC4364]. The routes received by these SAFIs are evaluated, in [RFC4364]. The routes received by these SAFIs are evaluated,
stored, and announced independently according to the rules of stored, and announced independently according to the rules of
[RFC4760]. The tiebreaking of route installation is a matter of the [RFC4760]. The tiebreaking of route installation is a matter of the
local policies and preferences of the network operator. local policies and preferences of the network operator.
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As previously stated, BGP-SPF can be deployed using the existing As previously stated, BGP-SPF can be deployed using the existing
peering model where there is a single-hop BGP session on each and peering model where there is a single-hop BGP session on each and
every link in the data center fabric [RFC7938]. This provides for every link in the data center fabric [RFC7938]. This provides for
both the advertisement of routes and the determination of link and both the advertisement of routes and the determination of link and
neighboring router availability. With BGP-SPF, the underlay will neighboring router availability. With BGP-SPF, the underlay will
converge faster due to changes to the decision process that will converge faster due to changes to the decision process that will
allow NLRI changes to be advertised faster after detecting a change. allow NLRI changes to be advertised faster after detecting a change.
5.2.1. Sparse Peering Model 5.2.1. Sparse Peering Model
Alternately, BFD [RFC5580] can be used to swiftly determine the Alternately, BFD [RFC5880] can be used to swiftly determine the
availability of links, and the BGP peering model can be significantly availability of links, and the BGP peering model can be significantly
sparser than the data center fabric. BGP-SPF sessions only need to sparser than the data center fabric. BGP-SPF sessions only need to
be established with enough peers to provide a biconnected graph. If be established with enough peers to provide a biconnected graph. If
Internal BGP (IBGP) is used, then the BGP routers at tier N-1 will Internal BGP (IBGP) is used, then the BGP routers at tier N-1 will
act as route-reflectors for the routers at tier N. act as route-reflectors for the routers at tier N.
The obvious usage of sparse peering is to avoid parallel BGP sessions The obvious usage of sparse peering is to avoid parallel BGP sessions
on links between the same two routers in the data center fabric. on links between the same two routers in the data center fabric.
However, this use case is not very useful since parallel L3 links However, this use case is not very useful since parallel L3 links
between the same two BGP routers are rare in Clos or Fat Tree between the same two BGP routers are rare in Clos or Fat Tree
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of the spines dependent on the flooding redundancy required to be of the spines dependent on the flooding redundancy required to be
reasonably certain that every node within the BGP-SPF routing domain reasonably certain that every node within the BGP-SPF routing domain
has the complete topology. has the complete topology.
Alternately, controller-based data center topologies are envisioned Alternately, controller-based data center topologies are envisioned
where BGP speakers within the data center only establish BGP sessions where BGP speakers within the data center only establish BGP sessions
with two or more controllers. In these topologies, fabric nodes with two or more controllers. In these topologies, fabric nodes
below the first tier, as shown in Figure 1 of [RFC7938], will below the first tier, as shown in Figure 1 of [RFC7938], will
establish BGP multi-hop sessions with the controllers. For the establish BGP multi-hop sessions with the controllers. For the
multi-hop sessions, determining the route to the controllers without multi-hop sessions, determining the route to the controllers without
depending on BGP would need to be through some other means beyond the depending on BGP would need to be through some other means, which is
scope of this document. However, the BGP discovery mechanisms beyond the scope of this document. However, the BGP discovery
described in Section 5.5 would be one possibility. mechanisms described in Section 5.5 would be one possibility.
5.2.2. Biconnected Graph Heuristic 5.2.2. Biconnected Graph Heuristic
With a biconnected graph heuristic, discovery of BGP SPF peers is With a biconnected graph heuristic, discovery of BGP SPF peers is
assumed, e.g., as described in Section 5.5. In this context, assumed, e.g., as described in Section 5.5. In this context,
"biconnected" refers to the fact that there must be an advertised "biconnected" refers to the fact that there must be an advertised
Link NLRI for both BGP and SPF peers associated with the link before Link NLRI for both BGP SPF peers associated with the link before the
the link can be used in the BGP SPF route calculation. Additionally, link can be used in the BGP SPF route calculation. Additionally, it
it is assumed that the direction of the peering can be ascertained. is assumed that the direction of the peering can be ascertained. In
In the context of a data center fabric, the direction is either the context of a data center fabric, the direction is either
northbound (toward the spine), southbound (toward the Top-of-Rack northbound (toward the spine), southbound (toward the Top-of-Rack
(ToR) routers), or east-west (same level in the hierarchy). The (ToR) routers), or east-west (same level in the hierarchy). The
determination of the direction is beyond the scope of this document. determination of the direction is beyond the scope of this document.
However, it would be reasonable to assume a technique where the ToR However, it would be reasonable to assume a technique where the ToR
routers can be identified and the number of hops to the ToR is used routers can be identified and the number of hops to the ToR is used
to determine the direction. to determine the direction.
In this heuristic, BGP speakers allow passive session establishment In this heuristic, BGP speakers allow passive session establishment
for southbound BGP sessions. For northbound sessions, BGP speakers for southbound BGP sessions. For northbound sessions, BGP speakers
will attempt to maintain two northbound BGP sessions with different will attempt to maintain two northbound BGP sessions with different
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session: session:
* The AS and BGP Identifier of a potential peer. * The AS and BGP Identifier of a potential peer.
* Supported security capabilities, and for cryptographic * Supported security capabilities, and for cryptographic
authentication, the security capabilities and possibly a key chain authentication, the security capabilities and possibly a key chain
[RFC8177] for use. [RFC8177] for use.
* A Session Policy Identifier, which is a group number or name used * A Session Policy Identifier, which is a group number or name used
to associate common session parameters with the peer. For to associate common session parameters with the peer. For
example, in a data center, BGP sessions with a ToR device could example, in a data center, BGP sessions with a ToR router could
have different parameters than BGP sessions between leaf and have different parameters than BGP sessions between leaf and spine
spine. nodes.
In a data center fabric, it is often useful to know whether a peer is In a data center fabric, it is often useful to know whether a peer is
southbound (towards the servers) or northbound (towards the spine or southbound (towards the servers) or northbound (towards the spine or
super-spine), e.g., see Section 5.2.2. One mechanism, without super-spine), e.g., see Section 5.2.2. One mechanism, without
specifying all the details, might be for the ToR routers to be specifying all the details, might be for the ToR routers to be
identified when installed and for the other routers in the fabric to identified when installed and for the other routers in the fabric to
determine their level based on the distance from the closest ToR determine their level based on the distance from the closest ToR
router. router.
If there are multiple links between BGP speakers or the links between If there are multiple links between BGP speakers or the links between
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To conserve IPv4 address space and simplify operations, BGP-SPF To conserve IPv4 address space and simplify operations, BGP-SPF
routers in Clos / Fat Tree deployments can use IPv6 addresses as the routers in Clos / Fat Tree deployments can use IPv6 addresses as the
peer address. For IPv4 address families, IPv6 peering as specified peer address. For IPv4 address families, IPv6 peering as specified
in [RFC8950] can be deployed to avoid configuring IPv4 addresses on in [RFC8950] can be deployed to avoid configuring IPv4 addresses on
router interfaces. When this is done, dynamic discovery mechanisms, router interfaces. When this is done, dynamic discovery mechanisms,
as described in Section 5.5, can be used to learn the global or link- as described in Section 5.5, can be used to learn the global or link-
local IPv6 peer addresses, and IPv4 addresses need not be configured local IPv6 peer addresses, and IPv4 addresses need not be configured
on these interfaces. If IPv6 link-local peering is used, then on these interfaces. If IPv6 link-local peering is used, then
configuration of IPv6 global addresses is also not required configuration of IPv6 global addresses is also not required
[RFC7404]. The Link Local/Remote Identifiers of the peering [RFC7404]. The Link Local/Remote Identifiers of the peering
interfaces MUST be used in the Link NLRI as described in interfaces must be used in the Link NLRI as described in
Section 5.2.2 of [RFC9815]. Section 5.2.2 of [RFC9815].
5.5.2. BGP-LS SPF Topology Visibility for Management 5.5.2. BGP-LS-SPF Topology Visibility for Management
Irrespective of whether or not BGP-SPF is used for route calculation, Irrespective of whether or not BGP-SPF is used for route calculation,
the BGP-LS-SPF route advertisements can be used to periodically the BGP-LS-SPF route advertisements can be used to periodically
construct the Clos / Fat Tree topology. This is especially useful in construct the Clos / Fat Tree topology. This is especially useful in
deployments where an Interior Gateway Protocol (IGP) is not used and deployments where an Interior Gateway Protocol (IGP) is not used and
the base BGP-LS routes [RFC9552] are not available. The resultant the base BGP-LS routes [RFC9552] are not available. The resultant
topology visibility can then be used for troubleshooting and topology visibility can then be used for troubleshooting and
consistency checking. This would normally be done on a central consistency checking. This would normally be done on a central
controller or other management tool that could also be used for controller or other management tool that could also be used for
fabric data path verification. The precise algorithms and fabric data path verification. The precise algorithms and
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Since BGP-SPF is to be used for the routing underlay and Data Center Since BGP-SPF is to be used for the routing underlay and Data Center
Interconnect (DCI) gateway boxes typically have direct or very simple Interconnect (DCI) gateway boxes typically have direct or very simple
connectivity, BGP external sessions would typically not include the connectivity, BGP external sessions would typically not include the
BGP-LS-SPF SAFI. BGP-LS-SPF SAFI.
6. Non-Clos / Fat Tree Topology Applicability 6. Non-Clos / Fat Tree Topology Applicability
The BGP-SPF extensions [RFC9815] can be used in other topologies and The BGP-SPF extensions [RFC9815] can be used in other topologies and
avail the inherent convergence improvements. Additionally, sparse avail the inherent convergence improvements. Additionally, sparse
peering techniques may be utilized Section 5.2. However, determining peering techniques may be utilized as described in Section 5.2.
whether to establish a BGP session is more complex, and the heuristic However, determining whether to establish a BGP session is more
described in Section 5.2.2 cannot be used. In such topologies, other complex, and the heuristic described in Section 5.2.2 cannot be used.
techniques such as those described in [RFC9667] may be employed. One In such topologies, other techniques such as those described in
potential deployment would be the underlay for a Service Provider [RFC9667] may be employed. One potential deployment would be the
(SP) backbone where usage of a single protocol, i.e., BGP, is underlay for a Service Provider (SP) backbone where usage of a single
desired. protocol, i.e., BGP, is desired.
7. Non-Transit Node Capability 7. Non-Transit Node Capability
In certain scenarios, a BGP node wishes to participate in the BGP-SPF In certain scenarios, a BGP node wishes to participate in the BGP-SPF
topology but never be used for transit traffic. These include topology but never be used for transit traffic. These include
situations where a server wants to make application services situations where a server wants to make application services
available to clients homed at subnets throughout the BGP-SPF domain available to clients homed at subnets throughout the BGP-SPF domain
but does not ever want to be used as a router (i.e., carry transit but does not ever want to be used as a router (i.e., carry transit
traffic). Another specific instance is where a controller is traffic). Another specific instance is where a controller is
resident on a server and direct connectivity to the controller is resident on a server and direct connectivity to the controller is
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accomplished using the BGP-LS-SPF Node NLRI Attribute SPF Status TLV accomplished using the BGP-LS-SPF Node NLRI Attribute SPF Status TLV
as described in [RFC9815]. as described in [RFC9815].
8. BGP Policy Applicability 8. BGP Policy Applicability
Existing BGP policy such as prefix filtering may be used in Existing BGP policy such as prefix filtering may be used in
conjunction with the BGP-LS-SPF SAFI. When BGP policy is used with conjunction with the BGP-LS-SPF SAFI. When BGP policy is used with
the BGP-LS-SPF SAFI, BGP speakers in the BGP-LS-SPF routing domain the BGP-LS-SPF SAFI, BGP speakers in the BGP-LS-SPF routing domain
will not all have the same set of NLRIs and will compute a different will not all have the same set of NLRIs and will compute a different
BGP local routing table. Consequently, care must be taken to assure BGP local routing table. Consequently, care must be taken to assure
routing is consistent and blackholes or routing loops do not ensue. that routing is consistent and that routes to unreachable
However, this is no different than if traditional BGP routing using destinations or routing loops do not ensue. However, this is no
the IPv4 and IPv6 address families were used. different than if classical BGP routing using the IPv4 and IPv6
address families were used.
9. IANA Considerations 9. IANA Considerations
This document has no IANA actions. This document has no IANA actions.
10. Security Considerations 10. Security Considerations
This document introduces no new security considerations above and This document introduces no new security considerations above and
beyond those already specified in [RFC4271] and [RFC9815]. beyond those already specified in [RFC4271] and [RFC9815].
11. References 11. References
11.1. Normative References 11.1. Normative References
[RFC9815] Patel, K., Lindem, A., Zandi, S., and W. Henderickx, "BGP [RFC9815] Patel, K., Lindem, A., Zandi, S., and W. Henderickx, "BGP
Link-State Shortest Path First (SPF) Routing", RFC 9815, Link State (BGP-LS) Shortest Path First (SPF) Routing",
DOI 10.17487/RFC9815, July 2025, RFC 9815, DOI 10.17487/RFC9815, July 2025,
<https://www.rfc-editor.org/info/rfc9815>. <https://www.rfc-editor.org/info/rfc9815>.
11.2. Informative References 11.2. Informative References
[Clos] Clos, C., "A Study of Non-Blocking Switching Networks", [Clos] Clos, C., "A Study of Non-Blocking Switching Networks",
The Bell System Technical Journal, vol. 32, no. 2, pp. The Bell System Technical Journal, vol. 32, no. 2, pp.
406-424, DOI 10.1002/j.1538-7305.1953.tb01433.x, March 406-424, DOI 10.1002/j.1538-7305.1953.tb01433.x, March
1953, 1953,
<https://doi.org/10.1002/j.1538-7305.1953.tb01433.x>. <https://doi.org/10.1002/j.1538-7305.1953.tb01433.x>.
skipping to change at line 532 skipping to change at line 534
[RFC4957] Krishnan, S., Ed., Montavont, N., Njedjou, E., Veerepalli, [RFC4957] Krishnan, S., Ed., Montavont, N., Njedjou, E., Veerepalli,
S., and A. Yegin, Ed., "Link-Layer Event Notifications for S., and A. Yegin, Ed., "Link-Layer Event Notifications for
Detecting Network Attachments", RFC 4957, Detecting Network Attachments", RFC 4957,
DOI 10.17487/RFC4957, August 2007, DOI 10.17487/RFC4957, August 2007,
<https://www.rfc-editor.org/info/rfc4957>. <https://www.rfc-editor.org/info/rfc4957>.
[RFC5340] Coltun, R., Ferguson, D., Moy, J., and A. Lindem, "OSPF [RFC5340] Coltun, R., Ferguson, D., Moy, J., and A. Lindem, "OSPF
for IPv6", RFC 5340, DOI 10.17487/RFC5340, July 2008, for IPv6", RFC 5340, DOI 10.17487/RFC5340, July 2008,
<https://www.rfc-editor.org/info/rfc5340>. <https://www.rfc-editor.org/info/rfc5340>.
[RFC5580] Tschofenig, H., Ed., Adrangi, F., Jones, M., Lior, A., and
B. Aboba, "Carrying Location Objects in RADIUS and
Diameter", RFC 5580, DOI 10.17487/RFC5580, August 2009,
<https://www.rfc-editor.org/info/rfc5580>.
[RFC5880] Katz, D. and D. Ward, "Bidirectional Forwarding Detection [RFC5880] Katz, D. and D. Ward, "Bidirectional Forwarding Detection
(BFD)", RFC 5880, DOI 10.17487/RFC5880, June 2010, (BFD)", RFC 5880, DOI 10.17487/RFC5880, June 2010,
<https://www.rfc-editor.org/info/rfc5880>. <https://www.rfc-editor.org/info/rfc5880>.
[RFC5925] Touch, J., Mankin, A., and R. Bonica, "The TCP [RFC5925] Touch, J., Mankin, A., and R. Bonica, "The TCP
Authentication Option", RFC 5925, DOI 10.17487/RFC5925, Authentication Option", RFC 5925, DOI 10.17487/RFC5925,
June 2010, <https://www.rfc-editor.org/info/rfc5925>. June 2010, <https://www.rfc-editor.org/info/rfc5925>.
[RFC7404] Behringer, M. and E. Vyncke, "Using Only Link-Local [RFC7404] Behringer, M. and E. Vyncke, "Using Only Link-Local
Addressing inside an IPv6 Network", RFC 7404, Addressing inside an IPv6 Network", RFC 7404,
skipping to change at line 592 skipping to change at line 589
Authors' Addresses Authors' Addresses
Keyur Patel Keyur Patel
Arrcus, Inc. Arrcus, Inc.
2077 Gateway Pl 2077 Gateway Pl
San Jose, CA 95110 San Jose, CA 95110
United States of America United States of America
Email: keyur@arrcus.com Email: keyur@arrcus.com
Acee Lindem Acee Lindem
LabN Consulting, L.L.C. Arrcus, Inc.
301 Midenhall Way 301 Midenhall Way
Cary, NC 95110 Cary, NC 27513
United States of America United States of America
Email: acee.ietf@gmail.com Email: acee.ietf@gmail.com
Shawn Zandi Shawn Zandi
LinkedIn Email: shafagh@shafagh.com
222 2nd Street
San Francisco, CA 94105
United States of America
Email: szandi@linkedin.com
Gaurav Dawra Gaurav Dawra
Linkedin Google
222 2nd Street Sunnyvale, CA
San Francisco, CA 94105
United States of America United States of America
Email: gdawra@linkedin.com Email: gdawra.ietf@gmail.com
Jie Dong Jie Dong
Huawei Technologies Huawei Technologies
No. 156 Beiqing Road No. 156 Beiqing Road
Beijing Beijing
China China
Email: jie.dong@huawei.com Email: jie.dong@huawei.com
 End of changes. 29 change blocks. 
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