Network Hub it is also called repeater.(Layer 1)
Hub it has different port.When packet arrive at one port .it is just receive and forward to all the port.if two port try to send in the same time the collision will occur in the Network.
switch efficiency than hub.
It will operate the data link layer and network layer.
switch it will read the packet header and identify which port needs to be send.when the data enters into the switch it is look up the destination MAC address. It will filter and forward the packet between LAN segment.(Layer 2).
Difference Between switch and Hub
Switch it will forward the packet only to the destination.( So it will take less time)
But hub broadcast packet to all the network.(it will take long time)
So switch is more efficiency than hub.
switch it will take the less time to send the packet but hub it will take the long time to receive because it send the data to the all the network. But switch it will send only to the destination.
it is also do the same job of switch.
It will read packet header and identify which ports need to be send and also translate the packet between different ports.
Router it is also include with DHCP.
Router Good example is broad band it will translate Home network IP to WAN IP.
What is port Number
Port Number it is way to identify the process to Internet or network when it arrives at the sever.