ConnectGear gs-1124 Betriebsanweisung

 

What is a VLAN? 

It is a subset of a LAN. Before we discuss VLAN, we must understand what 

LAN is. In general, a LAN is composed of different physical network segments 
bridged by switches or bridges which attach to end stations in the same broadcast 
domain. The traffic can reach any station on the same LAN. Beyond this domain, 
the traffic cannot go without router’s help. This also implies that a LAN is limited. If 
you need to communicate with the station outside the LAN, a router is needed 
which always lies on the edge of the LAN. 

For a layer 2 VLAN, it assumes it is a logical subset of a physical LAN 

separated by specific rules such as tag, port, MAC address and so on. In other 
words, they can communicate with each other between separated small physical 
LANs within a LAN but can not be between any two separated logical LANs. 

 

 

 

In the figure above, all stations are within the same broadcast domain. For 

these stations, it is obviously that the traffic is getting congested while adding more 
stations on it. With the more and more users joining the LAN, broadcast traffic will 
rapidly decrease the performance of the network. Finally, the network may get down. 

Fig. 3-7