- Repeater - operates at the physical layer. Its job is to regenerate the signal over the same network before the signal becomes too weak or corrupted.
- It does not amplify the signal.
- When the signal becomes weak, they copy the signal bit by bit and regenerate it at the original strength. It is a 2 port device.
- Hub - a device that allows multiple computers to communicate with each other over a network.They are similar to switches, but are not as "smart".Hubs cannot filter data, so data packets are sent to all connected devices.
They do not have intelligence to find out best path for data packets which leads to inefficiencies and wastage.
- Types:
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Active Hub - They have their own power supply and can clean, boost and relay the signal along with the network. It serves both as a repeater as well as wiring centre. These are used to extend the maximum distance between nodes.
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Passive Hub - They collect wiring from nodes and power supply from active hub. These hubs relay signals onto the network without cleaning and boosting them and can’t be used to extend the distance between nodes.
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Bridge – A bridge operates at data link layer (OSI layer2). A bridge is a repeater, with add on the functionality of filtering content by reading the MAC addresses of source and destination. It is also used for interconnecting two LANs working on the same protocol. It has a single input and single output port, thus making it a 2 port device.
- It does not analyze the data being forwarded.
- Not versatile - can not be used as firewall like routers
- A bridge can transfer data between different protocols (i.e. a Token Ring and Ethernet network).
- Bridges simply pass all protocols along the network. Therefore it is up to the individual computers to determine which protocols they can recognize.
- It is primarily used in local area networks because they can potentially flood and clog a large network thanks to their ability to broadcast data to all the nodes if they don’t know the destination node's MAC address.
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Switch - It is a multiport bridge with a buffer and a design that can boost its efficiency(a large number of ports imply less traffic) and performance. A switch is a data link layer device. The switch can perform error checking before forwarding data, that makes it very efficient as it does not forward packets that have errors and forward good packets selectively to correct port only.
It is more advanced than hubs and less capable than routers.Switches don't provide the firewall and logging capabilities that routers do. -
Routers - A router is a device like a switch that routes data packets based on their IP addresses. Router is mainly a Network Layer device. Routers normally connect LANs and WANs together and have a dynamically updating routing table based on which they make decisions on routing the data packets.Most routers also keep log files about the local network activity.Can act as firewall and block devices on a network.
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Gateway - is a passage to connect two networks together that may work upon different networking models. They basically work as the messenger agents that take data from one system, interpret it, and transfer it to another system. Gateways are also called protocol converters and can operate at any network layer.
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Brouter - It is also known as bridging router is a device which combines features of both bridge and router. It can work either at data link layer or at network layer. It can forward data between networks (serving as a bridge), but can also route data to individual systems within a network (serving as a router).
- The main purpose of a bridge is to connect two separate networks. It simply forwards the incoming packets from one network to the next. A router, on the other hand, is more advanced since it can route packets to specific systems connected to the router.
- A brouter combines these two functions by routing some incoming data to the correct systems, while forwarding other data to another network. In other words, a brouter functions as a filter that lets some data into the local network, while redirecting unrecognized data to another network.
- Actual brouters are pretty rare. Instead, most brouters are simply routers that have been configured to also function as a bridge.