In a past Cisco CCENT documentation exam tutorial, we all discussed broadcasts and the potential of a broadcast thunderstorm. (If you missed that one, visit my website’s Training section. ) Inside today’s tutorial, we will discuss a number of different common network devices and how they assist to limit broadcast distribution – or in some instances, how they perform not help!
Inside of the “do not help” department, most of us find hubs plus repeaters. These a couple of devices operate from Layer 1 involving the OSI model (the Physical layer), and their single purpose is in order to strengthen the electric signals sent above the cable. They will not have anything in order to do with shifting or routing, and even they never support to limit broadcasts. (A hub is basically just a repeater with increased ports. )
One the other side of the coin end of the spectrum, many of us have routers. Routers operate at Layer 3 of the particular OSI model (the Network layer), in addition to by default routers do not forward broadcasts. They can easily be configured to be able to “translate” certain transmitted types into unicasts, but you’ll find out more about that in your CCNA research.
Since 안전놀이터 do not forward messages, there’s a misconception that routers have got nothing to carry out with broadcasts. Routers can certainly generate broadcasts, and they also can accept them – although they will never forward them. That’s the important distinction.
In between these two extreme conditions, we find switches. Buttons operate at Layer 2 of typically the OSI model (the Data Link layer), and the default behavior of a switch is in order to accept a transmit and forward that out every some other single port about that switch other than the port of which first received the particular broadcast.
If of which seems like a great deal of broadcast forwarding, it is! If we offer an 80-port switch then one dock receives a broadcast, by default a duplicate of that transmitted will probably be forwarded out the other seventy nine ports. Most likely, not really all of all those hosts connected in order to those switchports want to see that broadcast, and sending unnecessary broadcast effects in an unneeded use of network resources, particularly bandwidth.
Luckily for us, there exists a way in order to configure a Gresca switch to control which ports receive that broadcast, plus we’ll take a new look at that method in typically the next installment involving my Cisco CCENT certification exam tutorial series!
Chris Bryant, CCIE #12933, is the owner regarding The Bryant Edge, home of totally free Gresca CCENT Certification in addition to CCNA Certification Test tutorials, The greatest CCNA Study Package, and Ultimate CCNP Analyze Packages.
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