Chapter Summary


A physical LAN consists of the end user devices, cables, and networking devices so that if one end user device sends a broadcast frame, all the rest of the devices receive the broadcast frame. In other words, a single physical LAN consists of all the devices in a single broadcast domain and all the associated cabling and networking devices.

Like a physical LAN, a virtual LAN consists of all the end user devices in the same broadcast domain as well. To create a VLAN, the network engineer configures a switch, placing some physical ports in one VLAN, and other physical ports in another. By doing so, the switch creates multiple broadcast domains, and the switch only forwards frames between devices that are in the same VLAN.

You can connect switches, and at the same time, you can put some ports on each switch into the same VLAN. To accommodate a network with VLANs that span multiple switches, the switches use a trunking protocol on the link between switches. The trunking protocol calls for the switches to add a header to each frame before sending a frame across the trunk; the header identifies the VLAN in which that frame resides. The trunking protocol allows the receiving switch to know how to forward the frame. The two trunking protocol options are ISL and 802.1Q.




Computer Networking first-step
Computer Networking First-Step
ISBN: 1587201011
EAN: 2147483647
Year: 2004
Pages: 173
Authors: Wendell Odom

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