Internet DRAFT - draft-liu-idr-bgp-network-slicing
draft-liu-idr-bgp-network-slicing
IDR Working Group Y. Liu
Internet-Draft S. Peng
Intended status: Standards Track ZTE
Expires: 2 October 2023 31 March 2023
BGP Extensions to Support Packet Network Slicing in SR Policy
draft-liu-idr-bgp-network-slicing-02
Abstract
This document defines extensions to BGP in order to advertise Network
Resource Partition (NRP) in SR policy.
Status of This Memo
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This Internet-Draft will expire on 2 October 2023.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 2
2. SR policy with NRP . . . . . . . . . . . . . . . . . . . . . 3
3. Operations . . . . . . . . . . . . . . . . . . . . . . . . . 4
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
5. Security Considerations . . . . . . . . . . . . . . . . . . . 5
6. References . . . . . . . . . . . . . . . . . . . . . . . . . 5
6.1. Normative References . . . . . . . . . . . . . . . . . . 5
6.2. Informative References . . . . . . . . . . . . . . . . . 5
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6
1. Introduction
[I-D.ietf-teas-ietf-network-slices] specified the definition of the
IETF Network Slice and the general principles of network slicing in
the IETF context. It introduced the concept of Network Resource
Partition (NRP), which is is a subset of the forwarding resources and
associated policies on each of a connected set of links in the
underlay network.
[I-D.ietf-teas-ns-ip-mpls] introduces the terminology NRP Identifier
(NRP-ID) which is globally unique within an NRP domain and that can
be used in the control or management plane to identify the resources
associated with the NRP.
[RFC9256] details the concepts of SR Policy and steering into an SR
Policy.[I-D.ietf-idr-segment-routing-te-policy] specifies the way to
use BGP to distribute one or more of the candidate paths of an SR
Policy to the headend of that policy.
This document defines extensions to BGP in order to advertise NRP-ID
in SR policy.
1.1. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119] [RFC8174]
when, and only when, they appear in all capitals, as shown here.
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2. SR policy with NRP
To distinguish forwarding behavior of different network slices, each
segment lists in SR policy need to be computed within the scope of
NRP identified by NRP-ID. As NRP has global significance, all
segments of the same segment list can share a single NRP. This
document defines a new NRP sub-TLV in Segment List Sub-TLV to
indicate which slice this segment list belongs to,
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=TBD1 | Length | Flags | RESERVED |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| NRP-ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: NRP sub-TLV in Segment List Sub-TLV
where,
* Type: TBD1
* Length: 6
* Flags: 1 octet of flags. None are defined at this stage. Flags
SHOULD be set to zero on transmission and MUST be ignored on
receipt
* RESERVED: 1 octet of reserved bits. SHOULD be set to zero on
transmission and MUST be ignored on receipt.
* NRP-ID: 4-octet identifier of Network Resource Partition of the
segment list.
The new SR Policy encoding structure with Path Segmentg sub-TLV is
expressed as below:
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SR Policy SAFI NLRI: <Distinguisher, Policy-Color, Endpoint>
Attributes:
Tunnel Encaps Attribute (23)
Tunnel Type: SR Policy
Binding SID
Preference
Priority
Policy Name
Explicit NULL Label Policy (ENLP)
Segment List
Weight
NRP-ID
Segment
Segment
Segment
...
Segment
Segment
Segment
...
...
3. Operations
The operations about advertisement and reception of SR policy can
refer to [I-D.ietf-idr-segment-routing-te-policy]. Typically, a
controller can compute SR path taking acount of NRP criteria, so that
the SR path can be limited in the scope of NRP identified by NRP-ID.
The controller can obtain the NRP virtual topology information
through necessary tools such BGP-LS, netconf, etc, and maintain the
database for the traffic engineering path computation. The proposal
in this document supports that multiple segment list each with
different NRP-ID, to meet the requirements that service flow is
carried by multiple network slices. However, it also support that
all segment list or all candidate path of the SR policy belongs to
the same slice.
The NRP information contained in Segment List Sub-TLV can help the
headend to translate the segment to NRP related SID, if the Segment
Sub-TLV has not provided optional SID information. Even if Segment
Sub-TLV has provided valid SID information, it is also beneficial for
the headend to know which slice this path belongs to, according to
the NRP information contained in Segment List Sub-TLV.
4. IANA Considerations
TBD
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5. Security Considerations
Procedures and protocol extensions defined in this document do not
affect the security considerations discussed in
[I-D.ietf-idr-segment-routing-te-policy].
6. References
6.1. Normative References
[I-D.ietf-idr-segment-routing-te-policy]
Previdi, S., Filsfils, C., Talaulikar, K., Mattes, P.,
Jain, D., and S. Lin, "Advertising Segment Routing
Policies in BGP", Work in Progress, Internet-Draft, draft-
ietf-idr-segment-routing-te-policy-20, 27 July 2022,
<https://datatracker.ietf.org/doc/html/draft-ietf-idr-
segment-routing-te-policy-20>.
[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>.
[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>.
6.2. Informative References
[I-D.bestbar-spring-scalable-ns]
Saad, T., Beeram, V. P., Chen, R., Peng, S., Wen, B., and
D. Ceccarelli, "Scalable Network Slicing over SR
Networks", Work in Progress, Internet-Draft, draft-
bestbar-spring-scalable-ns-02, 16 September 2021,
<https://datatracker.ietf.org/doc/html/draft-bestbar-
spring-scalable-ns-02>.
[I-D.ietf-teas-ietf-network-slices]
Farrel, A., Drake, J., Rokui, R., Homma, S., Makhijani,
K., Contreras, L. M., and J. Tantsura, "A Framework for
IETF Network Slices", Work in Progress, Internet-Draft,
draft-ietf-teas-ietf-network-slices-19, 21 January 2023,
<https://datatracker.ietf.org/doc/html/draft-ietf-teas-
ietf-network-slices-19>.
[I-D.ietf-teas-ns-ip-mpls]
Saad, T., Beeram, V. P., Dong, J., Wen, B., Ceccarelli,
D., Halpern, J. M., Peng, S., Chen, R., Liu, X.,
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Contreras, L. M., Rokui, R., and L. Jalil, "Realizing
Network Slices in IP/MPLS Networks", Work in Progress,
Internet-Draft, draft-ietf-teas-ns-ip-mpls-02, 13 March
2023, <https://datatracker.ietf.org/doc/html/draft-ietf-
teas-ns-ip-mpls-02>.
[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/info/rfc9256>.
Authors' Addresses
Yao Liu
ZTE
Nanjing
China
Email: liu.yao71@zte.com.cn
Shaofu Peng
ZTE
Nanjing
China
Email: peng.shaofu@zte.com.cn
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