Network devices

 Network bridge                                             

A network bridge, also known as a layer 2 switch, is a hardware device used to create a connection between two separate computer networks or to divide one network into two. Both networks usually use the same protocol; Ethernet is an example of a protocol. Network devices include, but are not limited to, Personal Computers (PCs), printers, routers, switches and hubs. Devices connected to a network via an Ethernet adapter card have what is known as a Media Access Control (MAC) address, also called a physical or hardware address. It is this address that uniquely identifies a device to a bridge that can then determine to which network the device is connected.

 Switch

Switch is a device that allocates traffic from one network segment to certain lines (intended destination(s)) which connect the segment to another network segment. So unlike a hub a switch splits the network traffic and sends it to different destinations rather than to all systems on the network. Works on OSI layer 2.

 Gateway

Gateway is a network point that acts as an entrance to another network. On the Internet, a node or stopping point node or a host (end-point) node. Both the computers of Internet users and the computers that serve pages to users are host nodes, while the nodes that connect the networks in between are gateways. For example, the computers that control traffic between company networks or the computers used by internet service providers (ISPs) to connect users to the internet are gateway nodes.

In the network for an enterprise, a computer server acting as a gateway node is often also acting as a proxy server and a firewall server. A gateway is often associated with both a router, which knows where to direct a given packet of data that arrives at the gateway, and a switch, which furnishes the actual path in and out of the gateway for a given packet.

 Router

In internet working, the process of moving a packet of data from source to destination. Routing is usually performed by a dedicated device called a router. Routing is a key feature of the Internet because it enables messages to pass from one computer to another and eventually reach the target machine. Each intermediary computer performs routing by passing along the message to the next computer. Part of this process involves analyzing a routing table to determine the best path.

Routing is often confused with bridging, which performs a similar function. The principal difference between the two is that bridging occurs at a lower level and is therefore more of a hardware function whereas routing occurs at a higher level where the software component is more important. And because routing occurs at a higher level, it can perform more complex analysis to determine the optimal path for the packet.