Текст страницы
Version 1.0
8 VLAN management
8.1 Overview
VLAN (Virtual Local Area Network) is a technology that divides devices in LAN into different
logical, instead of physical, network segments to form virtual working groups. VLANs allow a
network station constituted by switches to be logically segmented into different domains for
broadcast isolation. All members in a VLAN are treated as in the same broadcast domain and
communicate as if they were on the same network segment, regardless of their physical
locations. Different VLANs cannot intercommunicate directly. Inter-VLAN communication can
only be achieved using a router or other layer-3 devices that are able to perform layer-3
forwarding.
The switch supports 802.1Q VLAN and can communicate with devices that support 802.1Q
VLAN in VLAN as well.
As defined by IEEE 802.1q protocol, one 4 bytes 802.1Q VLAN tab is bound to be wrapped
behind the destination MAC address and the source MAC address of the Ethernet frame for
identifying the relevant information of VLAN. As shown below, the Ethernet frame with 802.1Q
tag is produced by adding an 802.1Q VLAN tag behind the destination MAC address and the
source MAC address of the standard Ethernet frame.
Chapter 8 VLAN management 21