June 15, 2020—

Network Virtualization over Clos topology – the data path: An interview with Dinesh Dutt

By: Silvano Gai


This article was originally posted on Silvano’s blog here.

This is the second post in a series of four, in which I interview Dinesh Dutt, a well-known engineer and author, and ask him to explain the Clos topology as applied to data center networks.

In the first post, we covered the basic notion of a two-tier Clos topology, emphasizing that the core of the network is a layer three routed infrastructure and that the layer two domains are restricted to the edge of the network.

In this post, Dinesh describes the basic principles of layer two network virtualization and a deep dive on VXLAN, which is the most used network virtualization standard. The discussion is on the data plane aspects.

The third post will continue the description of network virtualization, but it will focus on control plane considerations.

The fourth post will describe how to build multi-tier Clos networks to scale the number of ports.

This short video is an introduction to the topic of network virtualization.


The following podcast goes in more details about network virtualization, VXLAN, and Clos networks.


Dinesh book Cloud Native Data Center Networking published by O’Reilly in 2020, ISBN 9781492045601 has a lot of material on the topic.

Dinesh Book Cover


My book has a brief description of Clos in chapter 2.

Book Cover

You can read an independent review of the book here.

The book was also listed in The Top 10 Best Cloud Storage Books You Need to Read in 2020.

Don’t Forget that Pearson/Addison-Wesley has a special offer on my latest book. To save 35% on the book or eBook go to the informit website and use code FUTUREPROOF during checkout to apply the discount. Offer expires December 31, 2020

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