BGP Prefix Segment in Large-Scale Data Centers
RFC 8670
Document | Type | RFC - Informational (December 2019; No errata) | |
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Authors | Clarence Filsfils , Stefano Previdi , Gaurav Dawra , Ebben Aries , Petr Lapukhov | ||
Last updated | 2019-12-06 | ||
Replaces | draft-filsfils-spring-segment-routing-msdc | ||
Stream | IETF | ||
Formats | plain text html xml pdf htmlized bibtex | ||
Reviews | |||
Stream | WG state | Submitted to IESG for Publication | |
Document shepherd | Bruno Decraene | ||
Shepherd write-up | Show (last changed 2017-03-13) | ||
IESG | IESG state | RFC 8670 (Informational) | |
Action Holders |
(None)
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Consensus Boilerplate | Yes | ||
Telechat date | |||
Responsible AD | Alvaro Retana | ||
Send notices to | aretana.ietf@gmail.com | ||
IANA | IANA review state | Version Changed - Review Needed | |
IANA action state | No IANA Actions |
Internet Engineering Task Force (IETF) C. Filsfils, Ed. Request for Comments: 8670 S. Previdi Category: Informational Cisco Systems, Inc. ISSN: 2070-1721 G. Dawra LinkedIn E. Aries Arrcus, Inc. P. Lapukhov Facebook December 2019 BGP Prefix Segment in Large-Scale Data Centers Abstract This document describes the motivation for, and benefits of, applying Segment Routing (SR) in BGP-based large-scale data centers. It describes the design to deploy SR in those data centers for both the MPLS and IPv6 data planes. Status of This Memo This document is not an Internet Standards Track specification; it is published for informational purposes. This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Not all documents approved by the IESG are candidates for any level of Internet Standard; see Section 2 of RFC 7841. Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at https://www.rfc-editor.org/info/rfc8670. Copyright Notice Copyright (c) 2019 IETF Trust and the persons identified as the 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/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction 2. Large-Scale Data-Center Network Design Summary 2.1. Reference Design 3. Some Open Problems in Large Data-Center Networks 4. Applying Segment Routing in the DC with MPLS Data Plane 4.1. BGP Prefix Segment (BGP Prefix-SID) 4.2. EBGP Labeled Unicast (RFC 8277) 4.2.1. Control Plane 4.2.2. Data Plane 4.2.3. Network Design Variation 4.2.4. Global BGP Prefix Segment through the Fabric 4.2.5. Incremental Deployments 4.3. IBGP Labeled Unicast (RFC 8277) 5. Applying Segment Routing in the DC with IPv6 Data Plane 6. Communicating Path Information to the Host 7. Additional Benefits 7.1. MPLS Data Plane with Operational Simplicity 7.2. Minimizing the FIB Table 7.3. Egress Peer Engineering 7.4. Anycast 8. Preferred SRGB Allocation 9. IANA Considerations 10. Manageability Considerations 11. Security Considerations 12. References 12.1. Normative References 12.2. Informative References Acknowledgements Contributors Authors' Addresses 1. Introduction Segment Routing (SR), as described in [RFC8402], leverages the source-routing paradigm. A node steers a packet through an ordered list of instructions called "segments". A segment can represent any instruction, topological or service based. A segment can have a local semantic to an SR node or a global semantic within an SR domain. SR allows the enforcement of a flow through any topological path while maintaining per-flow state only from the ingress node to the SR domain. SR can be applied to the MPLS and IPv6 data planes. The use cases described in this document should be considered in the context of the BGP-based large-scale data-center (DC) design described in [RFC7938]. This document extends it by applying SR both with IPv6 and MPLS data planes. 2. Large-Scale Data-Center Network Design Summary This section provides a brief summary of the Informational RFC [RFC7938], which outlines a practical network design suitable for data centers of various scales: * Data-center networks have highly symmetric topologies with multiple parallel paths between two server-attachment points. The well-known Clos topology is most popular among the operators (as described in [RFC7938]). In a Clos topology, the minimum number of parallel paths between two elements is determined by the "width" of the "Tier-1" stage. See Figure 1 for an illustrationShow full document text