D-Link DES-5200, Руководство пользователя

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Fast Ethernet Switching System User’s Guide
Web Management
128
VLAN Port Management
A Virtual Local Area Network (VLAN) is a logical subgroup within a LAN that is
created with software rather than physical connections. The purpose of a VLAN is
to prevent broadcast storms and ease congestion on the network.
Each VLAN created is a broadcast domain. A broadcast is a packet that is sent to
all nodes on the network. A broadcast domain is a domain in which every node in
the domain receives the broadcast packet. The advantage of creating VLANs is
that they permit you to group LAN segments together in order to get the most out
of your network.
VLANs become more important as the network grows and traffic increases.
VLANs are usually used on high traffic networks. You should consider a VLAN
on a smaller network if a department or workgroup routinely does tasks that take
up a lot of bandwidth and they are not already on their own LAN segment.
VLANs can be used to subdivide the network. The DES-5200 supports port based
VLAN. Port based VLAN means that the VLAN is grouped by port. If a VLAN is
created using three ports, then those ports become a separate broadcast domain.
By using the VLANs, members of a particular department or workgroup can be
partitioned from the rest of the network. For example, the marketing department
can be on one VLAN and the accounting department can be on another. If a
workstation in marketing sends a broadcast packet to another workstation in
marketing the packet will remain in the marketing VLAN.