As you can see from the official documentation, those parameters (
broadcast) are not required.
(network, broadcast and gateway are optional)
In your example, your network would be
192.168.5.0/24 and your broadcast
192.168.5.255. These can be derived from your
netmask parameters. To understand these parameters and how to determine them, you need to read up on IP subnetting.
In my opinion, the
broadcast parameters can usually be omitted.
In IP, you usually have an address (
192.168.5.101) and a netmask (
The netmask explains how many of the bits in the address refer to the network and how many refer to the host. In this example, it's 24bits (that's what the netmask means, and that's what the
/24 means which you often see in this context).
These 24bits are exactly the
192.168.5 part of your address. This means, all machines with an address, that starts with
192.168.5 and a netmask of
/24, are in your same network.
The remaining part (the
101) is your host part. It identifies your single machine.
When taking an address and fill the host part with zeros (in binary), that is equivalent to the network (so,
192.168.5.0). If you fill the host part with ones (in binary), you get the default broadcast address (