In a past Cisco CCENT qualification exam tutorial, we all mentioned broadcasts plus the potential of a broadcast storm. (If you missed that one, check out my website’s Tutorials section. ) In today’s tutorial, most of us discuss many different normal network devices and how they help to limit broadcast propagation – or in some instances, how they do not help!
Found in the “do not really help” department, we’re going find hubs plus repeaters. These 2 devices operate from Layer 1 involving the OSI super model tiffany livingston (the Physical layer), and their bottom purpose is to be able to strengthen the electric signals sent over the cable. Indicate have anything in order to do with shifting or routing, plus they do not help to limit shows. (A hub is simply just a repeater with more ports. )
On the other end of the spectrum, many of us have routers. Routers operate at Part 3 of typically the OSI model (the Network layer), in addition to by default routers do not frontward broadcasts. They can certainly be configured to be able to “translate” certain broadcast types into unicasts, but you’ll learn more about of which inside your CCNA studies.
Since routers do not forward messages, there’s a misconception that routers include nothing to carry out with broadcasts. Routers can indeed generate broadcasts, and so they can recognize them – but they is not going to ahead them. That’s a good important distinction.
Involving these two opposites, we find switches. Switches operate at Layer 2 of the OSI model (the Data Link layer), and the standard behavior of some sort of switch is to accept a transmit and forward that out every additional single port about that switch other than the port that will first received typically the broadcast.
If sureman02 sounds like a whole lot of broadcast forwarding, it is! In case we have an 80-port switch then one slot receives a broadcast, by default a copy of that transmitted will be forwarded away the other 79 ports. Most likely, not all of these hosts connected in order to those switchports want to see that will broadcast, and giving unnecessary broadcast results in an unneeded use of system resources, particularly band width.
Luckily for all of us, you will find a way to configure a Gresca switch to limitation which ports acquire that broadcast, in addition to we’ll take a new look at that method in the next installment involving my Cisco CCENT certification exam tutorial series!
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