ConEx B. Briscoe
Internet-Draft BT
Intended status: Informational M. Sridharan
Expires: August 28, 2013 Microsoft
February 24, 2013
Network Performance Isolation in Data Centres using Congestion Policing
draft-briscoe-conex-data-centre-01
Abstract
This document describes how a multi-tenant (or multi-department) data
centre operator can isolate tenants from network performance
degradation due to each other's usage, but without losing the
multiplexing benefits of a LAN-style network where anyone can use any
amount of any resource. Zero per-tenant configuration and no
implementation change is required on network equipment. Instead the
solution is implemented with a simple change to the hypervisor (or
container) beneath the tenant's virtual machines on every physical
server connected to the network. These collectively enforce a very
simple distributed contract - a single network allowance that each
tenant can allocate among their virtual machines, even if distributed
around the network. The solution uses layer-3 switches that support
explicit congestion notification (ECN). It is best if the sending
operating system supports congestion exposure (ConEx). Nonetheless,
the operator can unilaterally deploy a complete solution while
operating systems are being incrementally upgraded to support ConEx
and ECN.
Status of This Memo
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Copyright Notice
Briscoe & Sridharan Expires August 28, 2013 [Page 1]
Internet-Draft Data Centre Network Performance Isolation February 2013
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Features of the Solution . . . . . . . . . . . . . . . . . . . 4
3. Outline Design . . . . . . . . . . . . . . . . . . . . . . . . 7
4. Performance Isolation: Intuition . . . . . . . . . . . . . . . 9
4.1. Performance Isolation: The Problem . . . . . . . . . . . . 9
4.2. Why Congestion Policing Works . . . . . . . . . . . . . . 11
5. Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
5.1. Trustworthy Congestion Signals at Ingress . . . . . . . . 13
5.1.1. Tunnel Feedback vs. ConEx . . . . . . . . . . . . . . 14
5.1.2. ECN Recommended . . . . . . . . . . . . . . . . . . . 14
5.1.3. Summary: Trustworthy Congestion Signals at Ingress . . 15
5.2. Switch/Router Support . . . . . . . . . . . . . . . . . . 16
5.3. Congestion Policing . . . . . . . . . . . . . . . . . . . 17
5.4. Distributed Token Buckets . . . . . . . . . . . . . . . . 18
6. Incremental Deployment . . . . . . . . . . . . . . . . . . . . 19
6.1. Migration . . . . . . . . . . . . . . . . . . . . . . . . 19
6.2. Evolution . . . . . . . . . . . . . . . . . . . . . . . . 20
7. Related Approaches . . . . . . . . . . . . . . . . . . . . . . 20
8. Security Considerations . . . . . . . . . . . . . . . . . . . 21
9. IANA Considerations (to be removed by RFC Editor) . . . . . . 21
10. Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . 21
11. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 21
12. Informative References . . . . . . . . . . . . . . . . . . . . 21
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