Cisco CCNA Certification: Defining Broadcast Domains

If you are studying to take the CCNA exam and earn your certification, you will be introduced to a large number of terms that are either entirely new to you or seem familiar, but you’re not sure what they are. The term “broadcast domain” falls into this category, many CCNA candidates.

A broadcast domain is simply the group of hosts at the end of a consignment of a particular host will be sent. For example, if host devices are connected to a switch ten and one of them sends a broadcast, the other nine devices is to receive the shipment. All these devices are in the same broadcast domain.

Of course, we probably do not want all devices on a network receive each broadcast by any other device on the network sent! Therefore, we need to know which devices can create several smaller broadcast domains. This allows us to limit emissions in order to travel on our network – and you will be surprised how much traffic there is on some networks from unnecessary emissions.

With the help of the OSI model, there are devices such as hubs and repeaters to the first layer. It is the physical layer and the equipment at this level has no effect on broadcast domains.

The layer two, we have switches and bridges. Does knowing default, a switch has no effect on broadcast domains, CCNA candidates that a change in an emission unique to each port, except the one on which it was received provided. However, it allows Cisco switches to create virtual LANs, or VLANs, the logical segments of the network. A shipment sent from a host in one VLAN will not be transferred to all other switch ports. This problem will only be transferred through the ports that members of the same VLAN as the host device has been sent.

The good news is that broadcast traffic will not be forwarded between VLANs. The bad news is that no inter-VLAN traffic by default at all is allowed! You may really want that in some cases, but usually you will have inter-VLAN traffic. This necessitates the use of a router or other Layer 3 device such as a Layer 3 switch. (Layer 3 switches are becoming popular. Basically is a switch that can also run the routing protocols. These switches are not tested on the CCNA exam.)

This router also defines broadcast domains just mentioned. Routers forward any broadcasts, so broadcast domains are defined by the routers without additional configuration.

Know-emissions journey through your network, and how it can be controlled, is an important part of being a CCNA and a director of network quality. Good luck to you in both activities!