Internet DRAFT - draft-watal-spring-srv6-sfc-sr-aware-functions
draft-watal-spring-srv6-sfc-sr-aware-functions
SPRING W. Mishima
Internet-Draft Y. Fukagawa
Intended status: Informational NTT Communications
Expires: 5 September 2024 4 March 2024
SRv6 SFC Architecture with SR-aware Functions
draft-watal-spring-srv6-sfc-sr-aware-functions-00
Abstract
This document describes the architecture of Segment Routing over IPv6
(SRv6) Service Function Chaining (SFC) with SR-aware functions. This
architecture provides the following benefits:
* Comprehensive management: a centralized controller for SFC,
handling SR Policy, link-state, and network metrics.
* Simplicity: no SFC proxies, so that reduces nodes and address
resource consumption.
Discussion Venues
This note is to be removed before publishing as an RFC.
Discussion of this document takes place on the Source Packet Routing
in Networking Working Group mailing list (spring@ietf.org), which is
archived at https://mailarchive.ietf.org/arch/browse/spring/.
Source for this draft and an issue tracker can be found at
https://https/github.com/watal.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on 5 September 2024.
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Copyright Notice
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document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents (https://trustee.ietf.org/
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Please review these documents carefully, as they describe your rights
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.1. Terminology Defined in Related RFCs and
Internet-Drafts . . . . . . . . . . . . . . . . . . . . . 3
2.2. Newly Defined Terminology . . . . . . . . . . . . . . . . 4
2.3. Requirements Language . . . . . . . . . . . . . . . . . . 4
3. Design Objectives and Assumptions . . . . . . . . . . . . . . 4
3.1. Assumptions . . . . . . . . . . . . . . . . . . . . . . . 5
4. Overview of Architecture . . . . . . . . . . . . . . . . . . 6
5. Forwarding Plane . . . . . . . . . . . . . . . . . . . . . . 8
5.1. End.AN-based Service Segment Provisioning . . . . . . . . 8
5.1.1. When a Network Function Goes Down . . . . . . . . . . 9
5.1.2. Anycast Segment . . . . . . . . . . . . . . . . . . . 9
5.1.3. Fast Reroute . . . . . . . . . . . . . . . . . . . . 9
5.2. Service Function Chains . . . . . . . . . . . . . . . . . 9
5.3. Per-Flow Encapsulation . . . . . . . . . . . . . . . . . 9
6. Control Plane . . . . . . . . . . . . . . . . . . . . . . . . 10
6.1. Service Function Controller . . . . . . . . . . . . . . . 11
6.2. Path Computation Element (PCE) . . . . . . . . . . . . . 11
6.3. Classification Rule Controller . . . . . . . . . . . . . 11
7. Management Plane . . . . . . . . . . . . . . . . . . . . . . 12
8. Normative References . . . . . . . . . . . . . . . . . . . . 13
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 15
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 15
1. Introduction
Segment Routing over IPv6 (SRv6) [RFC8986] enables packet steering
through a set of instructions called a segment list. Each SR segment
endpoint node provides SRv6 Endpoint Behaviors, including Prefix/
Adjacency segments, VPNs, and Binding Segments.
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Service Function Chaining (SFC) [RFC7665] can be used in various
scenarios (e.g. FW, IPS, IDS, NAT, and DPI). The SFC based on
Segment Routing (SR) is defined in
[I-D.draft-ietf-spring-sr-service-programming], which describes SFC
proxies like End.AS/AD/AM are necessary to use SR-unaware functions.
This document describes an architecture for SRv6 SFC with SR-aware
functions, which provides comprehensive management of SRv6 network
resources and services.
2. Terminology
2.1. Terminology Defined in Related RFCs and Internet-Drafts
The following terms are used in this document as defined in the
related RFCs and Internet-Drafts:
* SR, SR Domain, Segment ID (SID), SRv6, SR Policy, Prefix segment,
Adjacency segment, Anycast segment, Active segment, and
distributed/centralized/hybrid control plane defined in [RFC8402].
* SR source node, transit node, and SR segment endpoint node defined
in [RFC8754].
* SRv6 SID function and SRv6 Endpoint behavior defined in [RFC8986].
* SFC, SFC proxy, and service classification function defined in
[RFC7665].
* service segment, SR-aware service, SR-unaware Service, End.AS,
End.AD and End.AM defined in
[I-D.draft-ietf-spring-sr-service-programming].
* Headend, Color, and Endpoint defined in [RFC9256].
* Quality of Service (QoS), Service Level Agreement (SLA), and
Service Level Objective (SLO) defined in [RFC9522].
* forwarding plane (FP), control plane (CP), management plane (MP),
application plane (AP), northbound interface, southbound interface
defined in [RFC7426].
* Path Computation Client (PCC), Path Computation Element (PCE), and
Traffic Engineering Database (TED) defined in [RFC5440].
* BGP Flow Specification defined in [RFC8955]
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2.2. Newly Defined Terminology
The following terms are used in this document as defined below:
* SRv6 Service Function Node: an SR segment endpoint node that
provides SR-aware functions as service segments.
* Classification Rule Controller: applies sets of SR policy and
flows to SR Source Nodes.
* Service Function Controller: applies service segments to SRv6
Service Function Nodes.
* SRv6 Controller: controls SRv6 services comprehensively,
consisting of a Service Function Controller, a PCE, and a
Classification Rule Controller.
* SRv6 Managers: manage SRv6 SFC infrastructure, consisting of a
Virtualized Network Function (VNF) Manager, a Virtualized
Infrastructure Manager (VIM), and a data collector of network
metrics.
2.3. 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.
3. Design Objectives and Assumptions
## Goals/Objectives SRv6 SFC Architecture is designed with two main
objectives:
* Comprehensive management: a centralized controller for SFC,
handling SR Policy, link-state, and network metrics. When
providing SRv6 services, meeting SLAs for each customer is
required. These SLAs consist of one or more SLOs such as
availability, latency, and bandwidth. In an SRv6 SFC network,
service segment provisioning, link-state collection, and SR policy
calculation are required to meet SLOs, respectively.
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[RFC8402] outlines a hybrid control plane that merges a
distributed control plane and a centralized control plane. In
this hybrid control plane, forwarding information like Node/
Adjacency SIDs are advertised mutually by distributed SR nodes via
IGPs such as ISIS and OSPF, while other information like SR
Policies and service segments are provided by a centralized
controller.
Software-Defined Networking (SDN) [RFC7426] provides centralized
management of a network by a controller and a manager.
Centralized management reduces operational costs through
abstraction and automation. The SDN framework allows users to
manage an SR domain without considering the details of a
forwarding plane like a topology and node state. Operators can
use a SRv6 controller to build SR policies for SFC and QoS, manage
the state of network functions, issue service segments
automatically, and specify disaster recovery with protection.
* Simplicity: no SFC proxies, so that reduces nodes and address
resource consumption. Network complexity increases operating
costs. Generally, using a variety of protocols in a network
raises operational costs, including designing, building,
monitoring, and troubleshooting.
Using an SFC proxy may increase forwarding overhead due to
additional header manipulations.
3.1. Assumptions
To achieve these objectives, this architecture is based on two main
assumptions:
* Straightforward extension of the SRv6 Network Programming model
The protocol used in this architecture is compatible with SRv6.
This streamlines the operation of services like traffic steering,
including SFC, redundancy, and local protection. Standardized
protocols such as BGP, PCEP, IS-IS, OSPF, TI-LFA, and Anycast SID
are used in this architecture.
This architecture is SRv6 compliant, enabling support for SR-
unaware functions, although SR-aware functions are expected to
meet the objective.
* SDN Framework compliance and comprehensive management of SRv6 SFC
by controllers
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A controller is used to provide comprehensive management. To
simplify building and operating, the controller uses standardized
protocols and abstracted service interfaces. This also provides
programmability by controlling policies that meet a user's intent
including SFC and quality of service (QoS).
4. Overview of Architecture
Figure 1 illustrates an overview of this architecture.
+------------------------------------------------+
| Application Plane |
+------------------------|-----------------------+
| Control Plane Northbound Interface
+--- SRv6 Controller ----v-----------------------+
| +--------------+ +-------------+ +-----------+ | +-----------+
| |Classification| | Path | | Service | | | Service |
| | Rule | | Computation | | Function | | | Funtion |
| | Controller | |Element (PCE)| |Controller | | | Managers |
| +------|-------+ +-^---------|-+ +-----|-----+ | +-----|-----+
+--------|-----------|---------|---------|-------+ Management
| | | | Plane
Control Plane Southbound Interfaces Southbound
| | | | Interface
+--------|-----------|---------|---------|---------------|-------+
| +------v-----------|---------v-+ +-----v---------------v-----+ |
| | SRv6 SR Source Node / | | SRv6 Service | |
| | Service Classification |-| Function | |
| | Function | | Node | |
| +------------------------------+ +---------------------------+ |
+--------------------------- SR domain --------------------------+
Figure 1: Overview of SRv6 SFC Architecture with SR-aware Functions
This architecture is based on SDN [RFC7426] separating the forwarding
plane (FP), control plane (CP), management plane (MP), and
application plane (AP). Each plane has the following roles:
* Forwarding plane: classifies packets and encapsulates SRH,
forwards them, and applies endpoint behavior.
- Provides SR-aware function using End.AN.
- Classify flow and apply them to TE application with PBR.
- Ensures redundancy with Anycast.
- Ensure local protection with Fast Reroute (FRR).
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* Control plane: makes decisions about packet forwarding and
provides rules for a forwarding plane.
- Collects link-state including SRv6 locator, prefix, behavior,
and delay.
- Calculates and provisioning SR Policies.
- Applies SR Policies to each flow by provisioning flow
classification rules.
- Manages the provisioning of Service Segments to SR-aware
functions.
* Management plane: monitors and maintenances of SRv6 devices and
services
- Monitors and deploys network functions.
- Manages hypervisor resources.
- Collects metrics of devices, network functions, and SFC
services.
* Application plane: provides APIs for users to use a control and
management plane.
- Provide an interface to operators or customers.
- Applying intents defined in [RFC9315], including Operational,
Rule, Service, and Flow intents.
Each component communicates using standardized protocols. These are
designed to be loosely coupled and cooperate by using an abstraction
layer.
This document suggests handling a control plane by application plane,
but a detailed design of an application plane is out of the scope of
this document. This is because application plane components and
abstraction layers should be designed based on individual network
utilization and operator intent. In the following sections, details
of a forwarding plane, control plane, and management plane are
explained.
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5. Forwarding Plane
A forwarding plane is responsible for providing SFC through packet
classification, SRv6 encapsulation, and forwarding. In this
architecture, all forwarding plane components are located within the
SR domain.
+----------------------------------------------------------------+
| +--------------+ +--------+ +--------+ |
| | SRv6 SR | SRv6 Packet | SRv6 | SRv6 Packet | SRv6 | |
| | Source Node |(S2,S1; SL:1)|Service |(S2,S1; SL:1)|Service | |
-->| / Service |------------>|Function|------------>|Function|-->
| |Classification| | Node | | Node | |
| | Function | | (S1) | | (S2) | |
| +--------------+ +--------+ +--------+ |
+-------------------------- SR domain ---------------------------+
Figure 2: Forwarding Plane
Figure 2 shows an example of SFC with two network functions.
Firstly, the SRv6 SR source node classifies the flow and encapsulates
it with an SRH containing the segment list <S1, S2>. Next, the SRv6
Service Function Node (S1) receives the packet and applies a network
function associated with an End.AN S1. Finally, the SRv6 Service
Function Node (S2) receives the packet and also applies a network
function associated End.AN S2, thus achieving SFC.
5.1. End.AN-based Service Segment Provisioning
End.AN provides an SR-aware function.
Functions with the same role MAY be assigned as the same service
segment within the SR domain. By using Anycast-SIDs, multiple nodes
can be grouped as part of the same service segment.
End.AN MAY have optional arguments. This can provide additional
programmability by embedding network function instructions in the
segment list.
By using virtualized spaces within routers or on generic servers,
network functions can be provided at any node in an SR domain. This
allows for scaling and flexible redundancy of network functions.
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5.1.1. When a Network Function Goes Down
If a network function experiences a failure, the associated route
MUST be promptly removed. In the case of Anycast configuration, it
MUST be gracefully rerouted to other nodes. Additionally, if no
alternative nodes are available, consider either dropping the packet
and sending an ICMP Destination Unreachable message or forwarding it
as a pass-through.
5.1.2. Anycast Segment
The concept of the Anycast segment is introduced in [RFC8402]. In
the SRv6 SFC, it realizes to provide the same network function
segment as the same Anycast segment. In such cases, the state
between network functions MUST be shared mutually.
5.1.3. Fast Reroute
The ordering of network functions in an SRv6 SFC is guaranteed by the
segment list, even if an FRR occurs, When an FRR occurs, if the
Active segment is an Anycast SID, it MAY be forwarded to another SRv6
Service Function Node. In such a case, since state synchronization
may not have been completed, the network function MUST have a
mechanism to handle rerouted packets, such as buffering to wait for
synchronization.
5.2. Service Function Chains
In this architecture, each SFC is represented as an SRv6 Policy
[RFC9256]. The purpose or intent of each SRv6 Policy can be
identified using attributes such as color or name.
In general, SFC is achieved by using loose source routing. If both
SFC and QoS are desired, they can be achieved by using strict source
routing or loose source routing with Flex-Algo SIDs.
5.3. Per-Flow Encapsulation
In the SRv6 SR source node, which serves as the Service Classifier,
packets are classified on a per-flow basis using PBR and encapsulated
with SRv6 Policy. Therefore, the SRv6 SR source node MUST be capable
of identifying packets using at least a 5-tuple or even more detailed
information.
In this architecture, aiming for comprehensive management, the
service classifier has an API to communicate with the controller.
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6. Control Plane
A control plane is responsible for enabling comprehensive management
of SRv6 SFC. It enables SR-aware functions as service segments and
specifies SR Policies including SFC for each flow. A control plane
has a Northbound API to receive user requests and a Southbound API to
manipulate a forwarding plane.
+---------------- SRv6 Controller ----------------+
| +--------------+ +-------------+ +------------+ |
| |Classification| | Path | | Service | |
| | Rule | | Computation | | Function | |
| | Controller | |Element (PCE)| | Controller | |
| +------|-------+ +-^---------|-+ +------|-----+ |
+--------|-----------|---------|----------|-------+
Classification link-state SR Policy Enable/Disable
Rule (BGP-LS) (PCEP/BGP) a Service Segment
(BGP Flowspec) | | (End.AN SID:S1)
+--------|-----------|---------|----------|----------------------+
| +------v-----------|---------v-+ +------v--------------------+ |
| | SRv6 SR Source Node / | | SRv6 Service | |
| | Service Classification |-| Function | |
| | Function | | Node | |
| +------------------------------+ +---------------------------+ |
+--------------------------- SR domain --------------------------+
Figure 3: Control Plane
The SRv6 Controller consists of the following three components:
* Service Function Controller: provides an SID for a network service
and manages this state.
* PCE: provides SR Policies that fulfill SFC/QoS requirements from
the headend to the tailend and sends them to the SRv6 SR source
node.
* Classification Rule Controller: provides an Encapsulation Policy
that corresponds to a specific flow and SR Policy, and sends them
to the SRv6 SR source node.
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6.1. Service Function Controller
Service Function Controller is responsible for enabling and disabling
service segments of SRv6 Service Function Nodes. To manage service
segments, it utilizes the extensions provided in a BGP-LS service
segment, as outlined in
[I-D.draft-ietf-idr-bgp-ls-sr-service-segments] and TODO: draft-
watal-idr-bgp-ls-sr-service-segments-enabler, and defines the
following parameters:
* Behavior: End.AN
* SID: the SID of End.AN (in IPv6 Address format). Service segments
that support slicing are specified here as Flex-Algo SIDs.
* Function Name: type of network function
* Action: enable
* TLV:
- Specification of the Anycast Segment Group: when deploying
multiple Network Functions within the same context, it MUST use
the Anycast Group TLV to specify the same anycast segment group
SID.
- Allows for the specification of unique parameters and context
associated with a particular network function.
6.2. Path Computation Element (PCE)
PCE is a controller that provides SR Policy. As an Active Stateful
PCE, it establishes sessions with all PEs in an SR domain and manages
SFCs. SR Policies MUST support both explicit and dynamic paths. For
dynamic path, Constrained Shortest Path First (CSPF) considers not
only SFC but also QoS.
It acquires the Traffic Engineering Database (TED) of the SR domain
using BGP-LS and deploys SR Policies via PCEP [RFC5440] or BGP SR
Policy [I-D.draft-ietf-idr-segment-routing-te-policy]. The BGP-LS
service segment is required to calculate dynamic paths based on the
state of service segments and network functions.
6.3. Classification Rule Controller
A Classification Rule Controller determines flows to apply specific
SFC.
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The classification results are advertised to each SRv6 SR Source node
as a set of flow, endpoints, and color with an extended protocol
based on BGP Flowspec defined in
[I-D.draft-ietf-idr-ts-flowspec-srv6-policy].
7. Management Plane
A management plane is responsible for configuring network function
instances, monitoring resources, and collecting network metrics. The
details of each manager are outside the scope of this document, as
the southbound interface of the management plane may be different for
each service and hardware architecture.
+----------------- SRv6 Manager ------------------+
| +--------------+ +--------------+ +-----------+ |
| | Virtualized | | VNF | | Network | |
| |Infrastructure| | Manager | | Metric | |
| | Manager | | | | Manager | |
| +------^-------+ +------^-------+ +-----^-----+ |
+--------|----------------|---------------|-------+
| | |
Management Plane Southbound Interfaces
| | |
+--------|----------------|---------------|-------+
| +------|----------------v---------------|-----+ |
| | SRv6 Service | |
| | Function | |
| | Node | |
| +---------------------------------------------+ |
+------------------- SR domain -------------------+
Figure 4: Management Plane
Figure 4 shows examples of managers that MAY be added to a management
plane: * VNF Manager: handles deployment and scaling of network
functions. * This manager considers redundancy and link utilization
optimization.
* VIM: monitors hypervisor resources on SRv6 Service Function Node.
- In SRv6 SFC, a hypervisor managed by a VIM MAY be located in
virtualized spaces within routers or on generic servers.
* Network Metrics Manager: collects metrics for SRv6 policy
calculation and evaluation.
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- Metrics are collected from multiple data sources, including
IPFIX, TCP statistics, and SRv6 path tracing
[I-D.draft-filsfils-spring-path-tracing].
- Metrics can be used for PCE calculation parameters.
8. Normative References
[I-D.draft-filsfils-spring-path-tracing]
Filsfils, C., Abdelsalam, A., Camarillo, P., Yufit, M.,
Graf, T., Su, Y., Matsushima, S., Valentine, M., and
Dhamija, "Path Tracing in SRv6 networks", Work in
Progress, Internet-Draft, draft-filsfils-spring-path-
tracing-05, 23 October 2023,
<https://datatracker.ietf.org/doc/html/draft-filsfils-
spring-path-tracing-05>.
[I-D.draft-ietf-idr-bgp-ls-sr-service-segments]
Dawra, G., Filsfils, C., Talaulikar, K., Clad, F.,
Bernier, D., Uttaro, J., Decraene, B., Elmalky, H., Xu,
X., Guichard, J., and C. Li, "BGP-LS Advertisement of
Segment Routing Service Segments", Work in Progress,
Internet-Draft, draft-ietf-idr-bgp-ls-sr-service-segments-
02, 5 November 2022,
<https://datatracker.ietf.org/doc/html/draft-ietf-idr-bgp-
ls-sr-service-segments-02>.
[I-D.draft-ietf-idr-segment-routing-te-policy]
Previdi, S., Filsfils, C., Talaulikar, K., Mattes, P., and
D. Jain, "Advertising Segment Routing Policies in BGP",
Work in Progress, Internet-Draft, draft-ietf-idr-segment-
routing-te-policy-26, 23 October 2023,
<https://datatracker.ietf.org/doc/html/draft-ietf-idr-
segment-routing-te-policy-26>.
[I-D.draft-ietf-idr-ts-flowspec-srv6-policy]
Wenying, J., Liu, Y., Zhuang, S., Mishra, G. S., and S.
Chen, "Traffic Steering using BGP FlowSpec with SR
Policy", Work in Progress, Internet-Draft, draft-ietf-idr-
ts-flowspec-srv6-policy-03, 16 June 2023,
<https://datatracker.ietf.org/doc/html/draft-ietf-idr-ts-
flowspec-srv6-policy-03>.
[I-D.draft-ietf-spring-sr-service-programming]
Clad, F., Xu, X., Filsfils, C., Bernier, D., Li, C.,
Decraene, B., Ma, S., Yadlapalli, C., Henderickx, W., and
S. Salsano, "Service Programming with Segment Routing",
Work in Progress, Internet-Draft, draft-ietf-spring-sr-
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service-programming-09, 20 February 2024,
<https://datatracker.ietf.org/doc/html/draft-ietf-spring-
sr-service-programming-09>.
[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/rfc/rfc2119>.
[RFC5440] Vasseur, JP., Ed. and JL. Le Roux, Ed., "Path Computation
Element (PCE) Communication Protocol (PCEP)", RFC 5440,
DOI 10.17487/RFC5440, March 2009,
<https://www.rfc-editor.org/rfc/rfc5440>.
[RFC7426] Haleplidis, E., Ed., Pentikousis, K., Ed., Denazis, S.,
Hadi Salim, J., Meyer, D., and O. Koufopavlou, "Software-
Defined Networking (SDN): Layers and Architecture
Terminology", RFC 7426, DOI 10.17487/RFC7426, January
2015, <https://www.rfc-editor.org/rfc/rfc7426>.
[RFC7665] Halpern, J., Ed. and C. Pignataro, Ed., "Service Function
Chaining (SFC) Architecture", RFC 7665,
DOI 10.17487/RFC7665, October 2015,
<https://www.rfc-editor.org/rfc/rfc7665>.
[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/rfc/rfc8174>.
[RFC8402] Filsfils, C., Ed., Previdi, S., Ed., Ginsberg, L.,
Decraene, B., Litkowski, S., and R. Shakir, "Segment
Routing Architecture", RFC 8402, DOI 10.17487/RFC8402,
July 2018, <https://www.rfc-editor.org/rfc/rfc8402>.
[RFC8754] Filsfils, C., Ed., Dukes, D., Ed., Previdi, S., Leddy, J.,
Matsushima, S., and D. Voyer, "IPv6 Segment Routing Header
(SRH)", RFC 8754, DOI 10.17487/RFC8754, March 2020,
<https://www.rfc-editor.org/rfc/rfc8754>.
[RFC8955] Loibl, C., Hares, S., Raszuk, R., McPherson, D., and M.
Bacher, "Dissemination of Flow Specification Rules",
RFC 8955, DOI 10.17487/RFC8955, December 2020,
<https://www.rfc-editor.org/rfc/rfc8955>.
Mishima & Fukagawa Expires 5 September 2024 [Page 14]
Internet-Draft SRv6 SFC with SR-aware Functions March 2024
[RFC8986] Filsfils, C., Ed., Camarillo, P., Ed., Leddy, J., Voyer,
D., Matsushima, S., and Z. Li, "Segment Routing over IPv6
(SRv6) Network Programming", RFC 8986,
DOI 10.17487/RFC8986, February 2021,
<https://www.rfc-editor.org/rfc/rfc8986>.
[RFC9256] Filsfils, C., Talaulikar, K., Ed., Voyer, D., Bogdanov,
A., and P. Mattes, "Segment Routing Policy Architecture",
RFC 9256, DOI 10.17487/RFC9256, July 2022,
<https://www.rfc-editor.org/rfc/rfc9256>.
[RFC9315] Clemm, A., Ciavaglia, L., Granville, L. Z., and J.
Tantsura, "Intent-Based Networking - Concepts and
Definitions", RFC 9315, DOI 10.17487/RFC9315, October
2022, <https://www.rfc-editor.org/rfc/rfc9315>.
[RFC9522] Farrel, A., Ed., "Overview and Principles of Internet
Traffic Engineering", RFC 9522, DOI 10.17487/RFC9522,
January 2024, <https://www.rfc-editor.org/rfc/rfc9522>.
Acknowledgments
The authors would like to acknowledge the review and inputs from
Mitsuru Maruyama, Katsuhiro Sebayashi, Yuma Ito, and Taisei Tanabe.
We partially obtained the research results from NICT's commissioned
research No. JPJ012368C03101.
Authors' Addresses
Wataru Mishima
NTT Communications
Japan
Email: w.mishima@ntt.com
Yuta Fukagawa
NTT Communications
Japan
Email: y.fukagawa@ntt.com
Mishima & Fukagawa Expires 5 September 2024 [Page 15]
