Hubs may be any one of 3 types:
Passive hub is not powered and has a maximum distance of 30 meters from a powered device.
Active hub is powered and may extend a segment 100 meters. Always remember to abide by the
EIA/TIA standards for cabling lengths.
Intelligent hub is powered and may be used with SNMP (Simple network management protocol).
Repeaters are used to amplify digital signals.
Amplifiers are used to amplify analog signals.
The MAU or (MSAU) is at the center of the Token ring network, and looks similar to a switch with its
many ports.
None of the devices at the Physical layer can stop broadcasts (layer 3), or prevent collisions (layer 2).
Data link Layer devices
The NIC (Network interface card) has the MAC address that is used as our Ethernet address.
The Brouter is a combination router and bridge.
The Bridge is used to segment networks, and seperate collision domains. The 80/20 rule for Bridge
segmentation simply means that 80% of the network traffic should be local, while 20% may be remote.
The Switch is capable of creating multiple collision domains due to its higher port density. Each port is a seperate collision domain.
The switch is also capable of providing services for full duplex with its point to point connection. (A 10/100 Mbps full duplex switch would be capable of speeds of 20 Mbps or 200 Mbps in full duplex mode.
Network layer devices
The Router resides at the Network layer, and segments broadcast domains, as well as collision domains, compared to the Switch or the Bridge which can only segment collision domains.
There are layer 3 switches but they are outside the scope of the Network+ and the CCNA exams.
