Routers, Switches, Hubs – the terms are many times used interchangeably. However, each device has its own function in a network environment. Two reasons confusion may exist are (1) all three are simple boxes with several plugs that accept cables and (2) at times the functions of each device are rolled into one single device. For example, you might have purchased a router that has hub or switch capabilities.

A hub and switch have similar roles on the network. Each acts as a central connection for all the network equipment. Data packets are received by the hub or switch, then transmitted. The difference between a hub and switch is with how the data packets are delivered. 

The general concept of a hub is the data packet is sent to every port and every connected device regardless of the data packet’s address. The hub has no way of knowing which port or device should receive the data packet, but realizes that if it sends the data packet to every port and device (called boardcast) it will reach its intended destination eventually.    

A hub shares its bandwidth with all of the ports. If there is only one data packet being broadcasted, the packet has access to the maximum available bandwidth. If multipe deveices are broadcasting, the bandwidth is divided and the network response time is degraded. The possibility of data loss can also occur due to broadcast collisions.   

 A switch keeps track of the devices by storing each device’s physical address (called MAC or Media Access Control) in an information table (called a cache).  When the data packet is received, the switch can identify the correct device based on the MAC address and  forwards the data packet to the correct computer.   

A switch allocates all of its bandwidth to each port enabling  all users to have access to the maximum amount of bandwidth regardless of how many data packets are being sent. When using a switch instead of a hub, there is an improvement in network response time relative to a hub.  router is similar to a switch but it “routes” packets to other networks. Routers are located at the connection point or gateway for the networks and connect at least two networks. A common use for a router is to connect a LAN (Local Area Network) to WAN (Wide Area Network) that connects to DSL (Verizon) or Cable (Comcast) for broadband internet service. 

Routers not only provide connections to the internet, they also protect the LAN from the Internet. The router could block any Packet that has a destination address outside of the LAN. If the destination address is valid, the router could check the Packet for an error. If there is an error, the router could discard the Packet and send a message to the originating address. 

In short, a router can perform many of the same functions as switches and hubs, but it has address translation and filtering  capabilities. Depending on the router additional capabilities could be provided such as the linking of two routers, wireless access points, and built-in, configurable, hardware-based firewalls.