Welcome back. In the last lesson, we talked about some of the details surrounding the expansion of a CIDR block subnet. In this demonstration, I'm going to show you how to do it.

On the screen here, you can see that I'm logged in to my Google Cloud Platform Console. To expand my CIDR block subnet, I need to browse over here to the VPC Networks page. Now, from this page, I can see all of my networks and subnets in my project. Now, these are going to be shown, as you can see here, in a hierarchical view. My existing subnets are shown as entries within each of the networks.

What I need to do here is click the name of the network that contains the subnet that I want to expand. And we're going to expand my new subnet here. So we'll click test-network. From this VPC Network Details page I can then click the name of the subnet in the Subnets tab so I can view the subnet's details page.

Now, clicking Edit here allows me to enter a broader CIDR block in the IP address range field. I'll change this subnet from a /16 to a /15. What this does is make more addresses available for devices within this subnet. So, with my new CIDR block defined here, I just have to click Save to make it active.

Now, just a heads up, the expansion of the primary IP range of a subnet can actually take several minutes to complete. However, traffic within the subnet will continue to flow, unaffected, during the expansion. This process creates zero downtime.

Join me in the next lesson where we'll talk about reserving IP addresses.