Cloud Native Data Center Networking

Chapter 18. Validating Network Configuration

Computers are good at following instructions, but not at reading your mind.

Donald Knuth

After configuring the network, ensuring that it’s working as expected is the next critical step. As discussed in Chapter 10, network automation has unfortunately not progressed much beyond configuration. Old-world tools that rely on Simple Network Management Protocol (SNMP) suffer from critical limitations, especially in the context of the data center. Non-SNMP tools that gather, integrate, and present a unified view of the network are still largely missing, especially in a nonvendor-specific way and certainly not in open source. Although mainstream network operators have made some progress in their journey away from SNMP, the journey has not made much headway, even as much as configuration has.

This chapter deals with providing some ammunition to network operators to automate the validation of their network. It answers questions about how to validate the following:

• Network cabling

• Interface configuration

• Routing configuration

• Network virtualization

• Application connectivity

The lists of questions in this chapter are neither exhaustive or authoritative. Exhaustively listing every question and the ways to obtain the answer is an entire book by itself. Similarly, the way to obtain these answers is not authoritative, because the command syntax and the display can change over time.

Some Notes About the Code

I’ve relied on JSON outputs ...