Various Connecting Devices use at Physical layer
connecting devices can be classified in five ways:
1. Those who work below the physical layer
2. Those who work at the physical layer.
3. Those who work between the physical layer and data link layer
4.Those who operate at the physical layer data link layer and network layer.
5. Those who operated at all five layers. ex: gateway
1.Repeaters:
- A repeater works only at the physical layer.
- It is used to connects two or more segments of the same LAN.
- It does not connect two or more different LAN but it connects segments of same LAN.
- It is used to increase the domain of the LAN. When you have to increase the length of a LAN. you divide the LAN into multiple segments and connect those segments with the help of repeaters.
- A repeater is not an amplifying device. It does not amplify the signal.
- It generates the same signal on the other side of the LAN.
- Since it has only one layer Physical layer, it can't filter the packet it receives.
- Collison domain of a repeater is very high.
- A repeater placed on the line before the legibility of the signal
becomes lost can still read the signal well enough to determine the intended voltages and replicate them in their original form.
2. Hub:-
- A multiport repeater is called a hub.
- It works on the physical layer, So again like a repeater, it can't filter the packets.
- Collision Domain inside a hub is very high.