If you are using a DHCP server, you are basically safe. It's a good practice to release all ip addresses after certain time especially if you have temporary computer in the network.
DHCP
dhcp
Dynamic Host Configuration Protocol (DHCP) A protocol that provides a means to dynamically allocate IP addresses to computers on a local area network. The system administrator assigns a range of IP addresses to DHCP and each client computer on the LAN has its TCP/IP software configured to request an IP address from the DHCP server. The request and grant process uses a lease concept with a controllable time period.
distribution
More unique ip addresses, so essentially more devices on the network.
The correct answer is switch.
The Access Layer
These addresses are not assigned to devices because they have a reserved meaning. All zeroes refers to "this network", and all ones usually is assigned to a broadcast address (all devices).
The DHCP service.
It is what... DHCP is designed to automatically distributed IP addresses to connected to the same network devices.
Computers that are connected to each other create a network. These networks are often configured with "public" internet Protocol (IP) addresses -- that is, the devices on the network are "visible" to devices outside the network (from the Internet or another network). Networks can also be configured as "private" -- meaning that devices outside the network cannot "see" or communicate directly to them.
dns