Internet DRAFT - draft-dong-idr-flowspec-network-slice-ts
draft-dong-idr-flowspec-network-slice-ts
IDR Working Group J. Dong
Internet-Draft Huawei Technologies
Intended status: Standards Track R. Chen
Expires: 22 April 2023 ZTE Corporation
S. Wang
China Telecom
W. Jiang
China Mobile
19 October 2022
BGP Flowspec for IETF Network Slice Traffic Steering
draft-dong-idr-flowspec-network-slice-ts-01
Abstract
BGP Flow Specification (Flowspec) provides a mechanism to distribute
traffic flow specifications and the forwarding actions to be
performed to the specific traffic flows. A set of Flowspec
components are defined to specify the matching criteria that can be
applied to the packet, and a set of BGP extended communities are
defined to encode the actions a routing system can take on a packet
which matches the flow specification.
An IETF Network Slice enables connectivity between a set of Service
Demarcation Points (SDPs) with specific Service Level Objectives
(SLOs) and Service Level Expectations (SLEs) over a common underlay
network. To meet the connectivity and performance requirements of
network slice services, network slice service traffic needs to be
mapped to a corresponding Network Resource Partition (NRP). The edge
nodes of the NRP needs to identify the traffic flows which belong to
a network slice and steer the matched traffic into the corresponding
NRP, or a specific path within the corresponding NRP.
BGP Flowspec can be used to distribute the matching criteria and the
forwarding actions to be preformed on network slice service traffic.
The existing Flowspec components can be reused for the matching of
network slice services flows at the edge of an NRP. New components
and traffic action may need to be defined for steering network slice
service flows into the corresponding NRP. This document defines the
extensions to BGP Flowspec for IETF network slice traffic steering
(NS-TS).
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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Copyright (c) 2022 IETF Trust and the persons identified as the
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3
2. Matching Rules for Network Slice Traffic . . . . . . . . . . 4
2.1. NRP ID Component . . . . . . . . . . . . . . . . . . . . 4
3. Network Slice Traffic Steering Actions . . . . . . . . . . . 5
3.1. Traffic Steering to NRP BE Path . . . . . . . . . . . . . 5
3.1.1. Redirect to NRP specific Resource-aware Segment . . . 5
3.1.2. Encapsulate-NRP-ID Action . . . . . . . . . . . . . . 5
3.2. Traffic Steering to NRP TE Path . . . . . . . . . . . . . 6
4. Security Considerations . . . . . . . . . . . . . . . . . . . 7
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 7
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 7
7.1. Normative References . . . . . . . . . . . . . . . . . . 7
7.2. Informative References . . . . . . . . . . . . . . . . . 8
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10
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1. Introduction
BGP Flow Specification (Flowspec) [RFC8955] [RFC8956] and BGP Flow
Specification Version 2 [I-D.ietf-idr-flowspec-v2] provide the BGP
based mechanism to distribute traffic flow specifications and the
forwarding actions to be performed to the matched traffic flows. A
set of Flowspec components are defined to specify the matching
criteria that is applied to the packet, and a set of Traffic
Filtering Action are defined to encode the actions a routing system
can take on a packet which matches the flow specification.
[I-D.ietf-teas-ietf-network-slices] defines the term "IETF Network
Slice" and discusses the general framework for requesting and
operating IETF Network Slices, their characteristics, and the
necessary system components and interfaces. As described in
[I-D.ietf-teas-ietf-network-slices], an IETF Network Slice enables
connectivity between a set of Service Demarcation Points (SDPs) with
specific Service Level Objectives (SLOs) and Service Level
Expectations (SLEs) over a common underlay network. To meet the
connectivity and performance requirements, network slice services
needs to be mapped to a Network Resource Partition (NRP). An NRP is
a collection of resources (bufferage, queuing, scheduling, etc.) in
the underlay network. Each NRP can be idenified using a unique NRP
ID in control plane and management plane. The NRP ID may also be
encapsulated in data packet to guide the NRP-specific packet
forwarding. The edge nodes of an NRP needs to identify the traffic
which belong a network slice and steer the matched packets into the
corresponding NRP, so that the packet can be forwarded via either a
shortest path or a Traffic Engineering (TE) path within the NRP.
BGP Flowspec can be used to distribute the matching criteria and the
forwarding actions to be preformed on specific network slice
services. The existing Flowspec components can be reused for the
matching of network slice service flows. New components and traffic
actions may need to be defined for steering network slice service
flows into the corresponding NRP. This document defines the
extensions to BGP Flowspec for IETF Network Slice Traffic Steering
(NS-TS).
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.
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2. Matching Rules for Network Slice Traffic
A set of traffic matching rules can be used as the criteria to match
the traffic flows of an IETF network slice. The BGP Flowspec
components as defined in
[RFC8955] [RFC8956] can be used to specify the matching rules for
network slice service packets.
In some cases, data packets of IETF network slice services are
encapsulated with data plane NRP ID using the mechanisms as described
in [I-D.ietf-6man-enhanced-vpn-vtn-id]. A network domain edge node
may perform traffic matching based on the NRP ID in the packets, so
that the packets can be steered into a corresponding NRP in the local
domain. A new Flow component called NRP ID component is defined for
this purpose.
2.1. NRP ID Component
The format of the NRP ID component follows the Flowspec encoding as
defined in [I-D.ietf-idr-flowspec-v2], which consists of 1-octet type
field, 1-octet length field, and variable value field. The type of
NRP ID component is to be assigned by IANA. The format of the value
field is shown as below:
1 2 3 4
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|g| Flags | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| NRP ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Where
* Flags: 2-octet flag field. The first (most significant) bit is
defined in this document, the rest of the flag bits SHOULD be set
to zero on transmission and MUST be ignored on receipt.
Global bit (g): When set, it indicates the NRP ID to be matched
is a global unique NRP ID; otherwise the NRP ID is a domain
significant NRP ID.
* Reserved: 2-octet reserved bits. It SHOULD be set to zero on
transmission and MUST be ignored on receipt.
* NRP ID: A 4-octet identifier which is used to identify an NRP.
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3. Network Slice Traffic Steering Actions
For data packets which match the flow specification of a network
slice, specific forwarding actions need to be applied. When the
network slice service flows are mapped to an NRP in the underlay
network, the packets of the flows need to be forwarded in the
corresponding NRP using either a shortest (BE) path or a Traffic
Engineering (TE) path.
This section describes several actions to be performed on packets
which match the flow specification of a network slice.
3.1. Traffic Steering to NRP BE Path
Packets of a network slice service flow can be steered into an NRP
and forwarded to the NRP egress node following the shortest path with
the NRP. In this case, the identifier of the NRP needs to be carried
in the packet so that the packet forwarding will be performed using
the set of resources allocated to the NRP. Depends on the type of
the data plane NRP specific identifier, there are two options of this
traffic steering.
3.1.1. Redirect to NRP specific Resource-aware Segment
When resource-aware SR segments
[I-D.ietf-spring-resource-aware-segments] are used to represent the
network resources allocated to an NRP, packets of a network slice
could be steered into an NRP BE path by encapsulating the packets
with an resource-aware segment of the egress node in the NRP. For
SRv6 data plane, this could be achieved using the redirect-to-ip
action defined in [I-D.ietf-idr-flowspec-redirect-ip]. The mechanism
for SR-MPLS data plane will be specified in a future version.
3.1.2. Encapsulate-NRP-ID Action
When a data plane NRP ID [I-D.ietf-teas-nrp-scalability] is used to
identify the set of network resources allocated to an NRP, packets of
a network slice service flow could be steered into an NRP BE path by
encapsulating the NRP ID together with the IP address or the SR SID
of the egress node in the NRP.
For encapsulating the NRP ID to the matched packets, a new BGP
extended community is defined for the "Encapsulate-NRP-ID" action.
The format of this extended community is as below:
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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 | Sub-Type |E| Flags |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| NRP ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1. The format of Encapsulate-NRP-ID action
where:
* Type: 0x80. It belongs to the Generic Transitive Extended
Community Type as defined in [RFC9184].
* Sub-type: 1 octet to be assigned by IANA.
* Flags: 2-octet flag field. The first bit is defined in this
document. The rest of the flags are unused, which SHOULD be set
to zero on transmission and MUST be ignored on receipt.
Encapsulate (E) bit: When set, it indicates the NRP ID MUST be
encapsulated with an outer header to the packet. Otherwise the
NRP ID replaces the NRP ID in the existing header of the
packet.
* NRP ID: A 4-octet identifier which is used to identify an NRP.
If a packet matches the flow specification of an IETF network slice,
and the traffic actions associated with the flow specification is the
Encapsulate-NRP-ID action, then the packet is encapsulated with an
NRP ID in the packet header. The Encapsulate-NRP-ID action MAY be
used together with the "Rediect-to-IP" action as defined in
[I-D.ietf-idr-flowspec-redirect-ip], in that case the destination
address of the outer IP header is set to the IP address in the
redirect to IP next-hop action. The IPv6 encapsulation of NRP ID is
specified in [I-D.ietf-6man-enhanced-vpn-vtn-id]. The encapsulation
of NRP-ID in other data plane is for further study and out of the
scope of this document.
3.2. Traffic Steering to NRP TE Path
Packets of a network slice can be steered into a TE path within the
corresponding NRP. In an SR network, the network slice traffic can
be steered into an SR Policy [I-D.ietf-spring-segment-routing-policy]
which is associated with the corresponding NRP.
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In SR networks where the NRP is instantiated using NRP specific
resource-aware segments [I-D.ietf-spring-resource-aware-segments],
the segment list of the SR policy are built with resource-aware SR
segments which represents the set of network resources allocated to
the NRP on different network segments.
In SR networks where the data plane NRP-ID is used to identify the
set of network resources allocated to the NRP, the mechanism as
defined in[I-D.dong-idr-sr-policy-nrp] provides the BGP SR Policy
extensions to associate an SR Policy candidate path with an NRP-ID.
In both the above two cases, the mechanism defined in
[I-D.ietf-idr-ts-flowspec-srv6-policy] could be used to steer traffic
to an SR Policy which is associated with an NRP.
4. Security Considerations
The security considerations of BGP [RFC4271] and BGP Flowspec
[RFC8955] [RFC8956] apply to this document.
5. IANA Considerations
IANA is requested to assign a new type code point from "Flow Spec
Component Types" registry.
Type Value IPv4 Name IPv6 Name Reference
---------- ---------- ---------- -------------
TBA1 NRP ID NRP ID This document
IANA is requested to assign a new sub-type from "Generic Transitive
Extended Community Sub-Types" registry.
Value Description Reference
----- --------------------------- -------------
TBA2 Flowspec Encapsulate-NRP-ID This document
6. Acknowledgments
The authors would like to thank Haisheng Wu, Haibo Wang and Shunwan
Zhuang for the review and discussion of this document.
7. References
7.1. Normative References
[I-D.ietf-idr-flowspec-v2]
Hares, S., Eastlake, D., Yadlapalli, C., and S. Maduschke,
"BGP Flow Specification Version 2", Work in Progress,
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Internet-Draft, draft-ietf-idr-flowspec-v2-00, 19 April
2022, <https://www.ietf.org/archive/id/draft-ietf-idr-
flowspec-v2-00.txt>.
[I-D.ietf-teas-ietf-network-slices]
Farrel, A., Drake, J., Rokui, R., Homma, S., Makhijani,
K., Contreras, L. M., and J. Tantsura, "Framework for IETF
Network Slices", Work in Progress, Internet-Draft, draft-
ietf-teas-ietf-network-slices-14, 3 August 2022,
<https://www.ietf.org/archive/id/draft-ietf-teas-ietf-
network-slices-14.txt>.
[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>.
[RFC4271] Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A
Border Gateway Protocol 4 (BGP-4)", RFC 4271,
DOI 10.17487/RFC4271, January 2006,
<https://www.rfc-editor.org/info/rfc4271>.
[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>.
[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/info/rfc8955>.
[RFC8956] Loibl, C., Ed., Raszuk, R., Ed., and S. Hares, Ed.,
"Dissemination of Flow Specification Rules for IPv6",
RFC 8956, DOI 10.17487/RFC8956, December 2020,
<https://www.rfc-editor.org/info/rfc8956>.
[RFC9184] Loibl, C., "BGP Extended Community Registries Update",
RFC 9184, DOI 10.17487/RFC9184, January 2022,
<https://www.rfc-editor.org/info/rfc9184>.
7.2. Informative References
[I-D.dong-idr-sr-policy-nrp]
Dong, J., Hu, Z., and R. Pang, "BGP SR Policy Extensions
for Network Resource Partition", Work in Progress,
Internet-Draft, draft-dong-idr-sr-policy-nrp-01, 11 July
2022, <https://www.ietf.org/archive/id/draft-dong-idr-sr-
policy-nrp-01.txt>.
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[I-D.ietf-6man-enhanced-vpn-vtn-id]
Dong, J., Li, Z., Xie, C., Ma, C., and G. Mishra,
"Carrying Virtual Transport Network (VTN) Information in
IPv6 Extension Header", Work in Progress, Internet-Draft,
draft-ietf-6man-enhanced-vpn-vtn-id-01, 11 July 2022,
<https://www.ietf.org/archive/id/draft-ietf-6man-enhanced-
vpn-vtn-id-01.txt>.
[I-D.ietf-idr-flowspec-redirect-ip]
Uttaro, J., Haas, J., Texier, M., Karch, A., Ray, S.,
Simpson, A., and W. Henderickx, "BGP Flow-Spec Redirect to
IP Action", Work in Progress, Internet-Draft, draft-ietf-
idr-flowspec-redirect-ip-02, 5 February 2015,
<https://www.ietf.org/archive/id/draft-ietf-idr-flowspec-
redirect-ip-02.txt>.
[I-D.ietf-idr-ts-flowspec-srv6-policy]
Wenying, J., Liu, Y., Zhuang, S., Mishra, G. S., and S.
Chen, "Traffic Steering using BGP FlowSpec with SRv6
Policy", Work in Progress, Internet-Draft, draft-ietf-idr-
ts-flowspec-srv6-policy-01, 9 October 2022,
<https://www.ietf.org/archive/id/draft-ietf-idr-ts-
flowspec-srv6-policy-01.txt>.
[I-D.ietf-spring-resource-aware-segments]
Dong, J., Bryant, S., Miyasaka, T., Zhu, Y., Qin, F., Li,
Z., and F. Clad, "Introducing Resource Awareness to SR
Segments", Work in Progress, Internet-Draft, draft-ietf-
spring-resource-aware-segments-06, 11 October 2022,
<https://www.ietf.org/archive/id/draft-ietf-spring-
resource-aware-segments-06.txt>.
[I-D.ietf-spring-segment-routing-policy]
Filsfils, C., Talaulikar, K., Voyer, D., Bogdanov, A., and
P. Mattes, "Segment Routing Policy Architecture", Work in
Progress, Internet-Draft, draft-ietf-spring-segment-
routing-policy-22, 22 March 2022,
<https://www.ietf.org/archive/id/draft-ietf-spring-
segment-routing-policy-22.txt>.
[I-D.ietf-teas-nrp-scalability]
Dong, J., Li, Z., Gong, L., Yang, G., Guichard, J. N.,
Mishra, G., Qin, F., Saad, T., and V. P. Beeram,
"Scalability Considerations for Network Resource
Partition", Work in Progress, Internet-Draft, draft-ietf-
teas-nrp-scalability-00, 11 July 2022,
<https://www.ietf.org/archive/id/draft-ietf-teas-nrp-
scalability-00.txt>.
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[I-D.li-mpls-enhanced-vpn-vtn-id]
Li, Z. and J. Dong, "Carrying Virtual Transport Network
(VTN) Information in MPLS Packet", Work in Progress,
Internet-Draft, draft-li-mpls-enhanced-vpn-vtn-id-03, 16
October 2022, <https://www.ietf.org/archive/id/draft-li-
mpls-enhanced-vpn-vtn-id-03.txt>.
Authors' Addresses
Jie Dong
Huawei Technologies
Email: jie.dong@huawei.com
Ran Chen
ZTE Corporation
Email: chen.ran@zte.com.cn
Subin Wang
China Telecom
Email: wangsb6@chinatelecom.cn
Wenying Jiang
China Mobile
Email: jiangwenying@chinamobile.com
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