Barullo CCNA – CCENT Certification Exam Training – Broadcasts, Hubs, Routers, And Buttons

In a previous Cisco CCENT qualification exam tutorial, we all discussed broadcasts plus the potential associated with a broadcast thunderstorm. (If you skipped that one, check out my website’s Lessons section. ) Found in today’s tutorial, most of us discuss several different normal network devices and how they assistance to limit broadcast distribution – or in some instances, how they perform not help!
Inside the “do certainly not help” department, we’ll find hubs in addition to repeaters. These a couple of devices operate at Layer 1 of the OSI model (the Physical layer), and their sole purpose is to strengthen the power signals sent over the cable. They will not have anything to do with switching or routing, and even they never assist to limit messages. (A hub is actually just a repeater with increased ports. )
One the other side of the coin end of the spectrum, we have routers. Routers operate at Part 3 of the OSI model (the Network layer), and by default routers do not forwards broadcasts. They can be configured in order to “translate” certain broadcast types into unicasts, but you’ll study more about of which inside your CCNA scientific studies.
Since routers do not forward broadcasts, there’s a misconception that routers have nothing to conduct with broadcasts. Routers can indeed generate messages, and they can recognize them – although they will never frontward them. That’s a good important distinction.
Between these two extremes, we find switches. Switches operate at Layer 2 of typically the OSI model (the Data Link layer), and the arrears behavior of a switch is to accept a transmit and forward this out every some other single port about that switch except the port that will first received the particular broadcast.
If that will feels like a lot of broadcast forwarding, it is! If we come with an 80-port switch and one interface receives a transmission, by default a duplicate of that send out will be forwarded out the other 79 ports. More than likely, not all of those hosts connected to be able to those switchports will need to see that will broadcast, and sending unnecessary broadcast effects in an unnecessary use of community resources, particularly band width.
Luckily for us all, there is a way in order to configure a Gresca switch to restriction which ports obtain that broadcast, in addition to we’ll take some sort of look at that will method in typically the next installment associated with my Cisco CCENT certification exam article series!
Chris Bryant, CCIE #12933, is usually the owner of The Bryant Edge, home of totally free Carbonilla CCENT Certification and even CCNA Certification Test tutorials, The best CCNA Study Package, and even Ultimate CCNP Analyze Packages.
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