Your initial instinct might be to go with static. And I wouldn't blame you. After all, it is a small network. You'll likely have very little change. In the example its a network that won't have devices that frequently join and leave and they're not end-user devices. Static is a natural. Or is it?
How many devices do I need addresses for immediately? What is the maximum devices I expect for this network? When management won't buy new hardware and I have to squeeze even more devices in, how many can I possibly support before failure occurs? Hopefully you don't work in that environment, and between CIDR and supernetting you can be pretty flexible, but you still need to plan. Even if you only use a class C /24 network, you'll have 254 addresses to keep track of (yes, I know, you could subnet into a smaller network).
DHCP, even for a network of 5 devices, is a better option. At least, when you use DHCP reservations. A DHCP reservation links a MAC address with an assigned IP address. A simplified process goes something like this:
- Device or PC sends a DHCP request out onto the network.
- DHCP server (can be a firewall, router, Layer 3 switch, or actual DHCP server) sees the request and checks the device's MAC address against 2 tables. It checks both the assigned addresses (devices that have already received a random IP address) and it checks the DHCP reservation table. The reservation table lists IP addresses that are permanently assigned to specific MAC addresses. If either match it responds with the appropriate address. If not, it assigns a random address from the appropriate pool.
- The device or PC receives the address and begins using it.
Without DHCP, using static addresses, you get...a black hole.
Even for a small network, DHCP is your friend. It takes little time to set up, but if you don't I can promise that at some point you will wish you knew some detail about the network or you'll need to make a mass networking change to all devices and can't. And that means you'll be walking from one device to the next manually making the change. Enjoy your day!
If you still decide to go with static, let me just say now something that will certainly apply later, "I told you so".