BGP SR Policy Extensions for Network Resource Partition

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Table of Contents

1. Introduction

The concept of Segment Routing (SR) policy is defined in [I-D.ietf-spring-segment-routing-policy]. An SR Policy is a set of candidate paths, each consisting of one or more segment lists. The head end of an SR Policy may learn multiple candidate paths for an SR Policy. The header of a packet steered in an SR Policy is augmented with an ordered list of segments associated with that SR Policy. The BGP extensions to distribute SR Policy candidate paths is defined in [I-D.ietf-idr-segment-routing-te-policy].¶

The concept of Virtual Transport Network (VTN) is introduced in [I-D.ietf-teas-enhanced-vpn]. A VTN is a virtual underlay network which has customized network topology and a set of dedicated or shared network resources. In a network, multiple VTNs may be created to meet different service requirements, and services can be mapped to the same or different VTNs. [I-D.ietf-teas-ietf-network-slices] introduces the concept Network Resource Partition (NRP) as a set of network resources that are available to carry traffic and meet the SLOs and SLEs. In the context of network slicing, an NRP can be used to instantiate a VTN for one or a group of IETF network slice services. As described in [I-D.dong-teas-nrp-scalability], one scalable data plane approach is to carry a global NRP ID in the data packet to identify the NRP the packet belongs to, so that the packet can be processed and forwarded using the network resources allocated to the NRP.¶

In networks where multiple NRPs exist, the identifier of NRP in which the SR policy is instantiated need to be specified, so that at the ingress node of SR policy, the header of data packet can also be augmented with the identifier of the NRP. This document defines the BGP extensions to specify the NRP ID associated with a candidate path of SR policy.¶

2. Specification of Requirements

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 RFC 2119 [RFC2119].¶

5. Security Considerations

The security considerations of BGP and BGP SR policy apply to this document.¶

6. IANA Considerations

IANA has assigned the sub-TLV type as defined in Section 3 from "BGP Tunnel Encapsulation Attribute sub-TLVs" registry.¶

      Value     Description                     Reference
      ----------------------------------------------------
       123        NRP                         This document

7. Acknowledgments

The authors would like to thank Guoqi Xu, Lei Bao and Haibo Wang for the review and discussion of this document.¶

Authors' Addresses