Cloud Native Data Center Networking: Architecture, Protocols, and Tools

486 Pages·2019·7.372 MB·English

by  Dinesh G. Dutt

Cloud Native
Data Center
Networking
Architecture, Protocols, and Tools
Dinesh G. Dutt

Praise for Cloud Native Data Center Networking
Cloud Native Data Center Networking is a must-read book for anyone deploying and
automating a modern spine-and-leaf, agile data center fabric. The book’s focus on
automation and simplification is the future of networking.
—Donald Sharp, FRRouting Maintainer
Great read for any network engineer who wants to apply cloud native concepts to today’s
enterprise networks, but isn’t sure where to start. The book has something for all levels of
expertise, from high level architecture discussions to hands-on implementation examples
you can follow.
—Anthony Miloslavsky, Network Engineer
Dinesh Dutt is the greatest evangelist for data center networks and network device
disaggregation. The clarity of his thinking and his capability to explain hard concepts
with simple words never stops to amaze me.
—Silvano Gai, former University Professor and Fellow

Cloud Native Data Center
Networking
Architecture, Protocols, and Tools
Dinesh G. Dutt
BBeeiijjiinngg BBoossttoonn FFaarrnnhhaamm SSeebbaassttooppooll TTookkyyoo
Cloud Native Data Center Networking
by Dinesh G. Dutt
Copyright © 2020 Dinesh G. Dutt. All rights reserved.
Printed in the United States of America.
Published by O’Reilly Media, Inc., 1005 Gravenstein Highway North, Sebastopol, CA 95472.
O’Reilly books may be purchased for educational, business, or sales promotional use. Online editions are
also available for most titles (http://oreilly.com). For more information, contact our corporate/institutional
sales department: 800-998-9938 or [email protected].
Development Editor: Andy Oram Indexer: WordCo Indexing Services, Inc.
Acquisitions Editor: John Devins Interior Designer: David Futato
Production Editor: Katherine Tozer Cover Designer: Karen Montgomery
Copyeditor: Octal Publishing, LLC Illustrator: Rebecca Demarest
Proofreader: Sonia Saruba
November 2019: First Edition
Revision History for the First Edition
2019-11-19: First Release
2020-01-03: Second Release
See http://oreilly.com/catalog/errata.csp?isbn=9781492045601 for release details.
The O’Reilly logo is a registered trademark of O’Reilly Media, Inc. Cloud Native Data Center Networking,
the cover image, and related trade dress are trademarks of O’Reilly Media, Inc.
The views expressed in this work are those of the author, and do not represent the publisher’s views.
While the publisher and the author have used good faith efforts to ensure that the information and
instructions contained in this work are accurate, the publisher and the author disclaim all responsibility
for errors or omissions, including without limitation responsibility for damages resulting from the use of
or reliance on this work. Use of the information and instructions contained in this work is at your own
risk. If any code samples or other technology this work contains or describes is subject to open source
licenses or the intellectual property rights of others, it is your responsibility to ensure that your use
thereof complies with such licenses and/or rights.
978-1-492-04560-1
[LSI]
This book is dedicated to all who make networking—the network designers and architects
who plan the systems, the engineers, and the operators who bring them into being. And espe‐
cially to the open source networking community: may the fire never stop.

Table of Contents
Preface. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xvii
1. The Motivations for a New Network Architecture. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
The Application-Network Shuffle 1
The Network Design from the Turn of the Century 5
The Charms of Bridging 6
Building Scalable Bridging Networks 9
The Trouble with the Access-Aggregation-Core Network Design 13
Unscalability 13
Complexity 14
Failure Domain 15
Unpredictability 16
Inflexibility 16
Lack of Agility 17
The Stories Not Told 17
Summary 18
2. Clos: Network Topology for a New World. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Introducing the Clos Topology 20
A Deeper Dive into the Clos Topology 22
Use of Homogeneous Equipment 22
Routing as the Fundamental Interconnect Model 22
Oversubscription in a Clos Topology 24
Interconnect Link Speeds 25
Practical Constraints 26
Fine-Grained Failure Domain 28
Scaling the Clos Topology 29
Comparing the Two Three-Tier Models 31
vii
Application Matchup 31
Data Center Build Out 31
Implications of the Clos Topology 32
Rethinking Failures and Troubleshooting 32
Cabling 33
Simplified Inventory Management 33
Network Automation 33
Some Best Practices for a Clos Network 33
Use of Multiple Links Between Switches 33
Use of Spines as Only a Connector 34
Use of Chassis as a Spine Switch 35
Host Attach Models 36
Summary 37
References 38
3. Network Disaggregation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
What Is Network Disaggregation? 39
Why Is Network Disaggregation Important? 42
Controlling Costs 42
Avoiding Vendor Lock-In 43
Standardization of Features 43
What Made Network Disaggregation Possible Now? 43
Difference in Network Operations with Disaggregation 44
Purchase and Support 44
First Boot 45
Open Network Installer Environment 46
How Does ONIE Work? 47
The Players in Network Disaggregation: Hardware 48
Packet-Switching Silicon 48
ODMs 49
CPU Complex 49
The Standards Bodies 49
Common Myths About Network Disaggregation 50
Some Best Practices for Engaging with Network Disaggregation 51
Summary 52
References 52
4. Network Operating System Choices. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
Requirements of a Network Device 54
The Rise of Software-Defined Networking and OpenFlow 55
More Details About SDN and OpenFlow 56
The Trouble with OpenFlow 58
viii | Table of Contents