Virtual LAN Overview

One problem with early flat networks is the amount of broadcasts that are sent to every networking device. Remember that a flat, bridged network sends all broadcast packets that are generated by any device in the network to all other devices in the network. The ambient level of broadcasts that are generated by the higher-layer protocols in the network, known as broadcast radiation, typically restricts the total number of devices that the network can support. In extreme cases, the effects of broadcast radiation can be so severe that an end station spends all of its CPU power on processing broadcasts.

The virtual LAN (VLAN) concept was designed to address the broadcast radiation problem, along with the following problems that ...

Get CCIE Practical Studies: Security (CCIE Self-Study) now with O’Reilly online learning.

O’Reilly members experience live online training, plus books, videos, and digital content from 200+ publishers.