BGP Prefix Segment in Large-Scale Data Centers
RFC 8670
| Document | Type | RFC - Informational (December 2019; No errata) | |
|---|---|---|---|
| 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)
|
||
| 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 illustration
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