->A “hub” is nothing more than a repeater with multiple ports. Any voltage change it detects on one port gets sent to all the others. This piece of hardware has no intelligence, no CPU, no memory, or anything of the sort. It is a very simple, physical device.
->A “switch” can be thought of as a smart hub. It is able to send information directly to the computer that needs it, rather than broadcasting everything out every port. It does this by reading the destination and source “MAC” or “Media Access Control” addresses on messages that it receives, and building a database linking its physical ports to the MAC addresses that are sending information on those ports.
->A “router” doesn't just read destination and source MAC addresses, but in an IP network it can also read IP addresses, and forward traffic based on that information. While switches can connect computers within a network, routers can connect multiple networks together. They can also run “routing protocols”, or mechanisms for routers to learn about each other, and decide as a group how to best send traffic from source to destination.
So, these three pieces of hardware work on different “layers”. Hubs are purely physical devices with no intelligence, and thus can be referred to as “physical layer” or “layer 1” devices. Switches can forward information based on the first header, or the “frame encapsulation” of a network message, and so they are “layer 2” devices. Routers can route traffic based on the next (typically IP) header, so they can be considered “network layer” or “layer 3” devices. Just think of networking like an onion.
This answer is long, but still a little simplified. There are multi-layer switches, and modular devices with routing and switching modules, but the above gives you a pretty good idea. I guess the definitive difference between a router and a switch would be that switches use application-specific integrated circuits to "switch" traffic rather than using a typical CPU to "route" traffic.
->A hub is a multiport repeater of broadcast information (it receives on any port) to all ports hence is called non-intelligent or dumb. A hub repeats a message to all the nodes connected to its ports.
Hubs translate any signal from one PC to all others in the same network. Switches translate from one PC only to a certain PC, not to all of them as is the case with hubs.
HUB works on Physical layer whereas SWITCH works on data link layer, HUB based networks are on one collision domain, whereas in Switch-based networks, a switch divides networks into multiple collision domains. Switch also maintains MAC address tables.
A Simple Simile
Hub - Think of a postman with a letter to deliver in a row of houses, none of the houses have numbers so he has to visit each house and ask the owner if the letter is for them.
Switch - All the houses are numbered, so the postman knows where to go, and doesn't have to bother any other homeowners.
That is the reason a HUB is called a Dumb Device (or Dumb Postman).
->A “switch” can be thought of as a smart hub. It is able to send information directly to the computer that needs it, rather than broadcasting everything out every port. It does this by reading the destination and source “MAC” or “Media Access Control” addresses on messages that it receives, and building a database linking its physical ports to the MAC addresses that are sending information on those ports.
->A “router” doesn't just read destination and source MAC addresses, but in an IP network it can also read IP addresses, and forward traffic based on that information. While switches can connect computers within a network, routers can connect multiple networks together. They can also run “routing protocols”, or mechanisms for routers to learn about each other, and decide as a group how to best send traffic from source to destination.
So, these three pieces of hardware work on different “layers”. Hubs are purely physical devices with no intelligence, and thus can be referred to as “physical layer” or “layer 1” devices. Switches can forward information based on the first header, or the “frame encapsulation” of a network message, and so they are “layer 2” devices. Routers can route traffic based on the next (typically IP) header, so they can be considered “network layer” or “layer 3” devices. Just think of networking like an onion.
This answer is long, but still a little simplified. There are multi-layer switches, and modular devices with routing and switching modules, but the above gives you a pretty good idea. I guess the definitive difference between a router and a switch would be that switches use application-specific integrated circuits to "switch" traffic rather than using a typical CPU to "route" traffic.
->A hub is a multiport repeater of broadcast information (it receives on any port) to all ports hence is called non-intelligent or dumb. A hub repeats a message to all the nodes connected to its ports.
Hubs translate any signal from one PC to all others in the same network. Switches translate from one PC only to a certain PC, not to all of them as is the case with hubs.
HUB works on Physical layer whereas SWITCH works on data link layer, HUB based networks are on one collision domain, whereas in Switch-based networks, a switch divides networks into multiple collision domains. Switch also maintains MAC address tables.
A Simple Simile
Hub - Think of a postman with a letter to deliver in a row of houses, none of the houses have numbers so he has to visit each house and ask the owner if the letter is for them.
Switch - All the houses are numbered, so the postman knows where to go, and doesn't have to bother any other homeowners.
That is the reason a HUB is called a Dumb Device (or Dumb Postman).
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