IP reservation is the process of assigning a specific IP address to a device, such as a computer, so it receives the same address each time it (re)connects to the network, such as when you restart it ...
There's a number of options in your router for IP management that you may need, but is DHCP or a Static IP the right choice ...
An internet protocol (IP) address is a unique identifying number assigned to a device that connects to the internet. It functions as an online device address―characterized by a string of numbers―used ...