1. A hub as the term denotes is a common connection point for devices in a network. It is commonly use to connect segment in a network. when a packet(data) arrives at one port, it is copied to other ports so all segments on the LAN can see all packet. It does not matter a frame is destined for one port, the hub has no way of distinguishing which port a frame should be sent to. To ensure that a frame gets to it destination,it passes the frame to each port. They usually operate at the physical layer.
3. A Router is a networking device that forwards data packets between computer networks. Routers perform the "traffic directing" functions on the Internet. A packet(data) is typically forwarded from one router to another through the networks that constitute the internetwork until it reaches its destination node. It located at the network layer.
4. Bridge is a device that connects multiple network segments. OSI layer 1 and 2 is were a bridge works at.
5. Repeater is usually for connecting multiple Ethernet devices together and making them act as a single network segment.
6. Gateway is an interface providing a compatibility between networks by converting transmission speeds, protocols, codes.
7. NIC is a device connecting a computer to a wire-based computer network.
8. Firewall: A firewall is a network security system designed to prevent unauthorized access to or from a private network. Firewalls can be implemented as both hardware and software, or a combination of both.
