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Switch Operation and Features
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Implementing VLANs on your network has three main advantages:
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Network administration personnel are required to make le ss physical
intervention when a workstation has to be moved. Within the VLAN
setup, a group of devices on different floors in a building can be
configured into a common communications group. If a workstation is
moved from VLAN 1 to VLAN 2 for example, the network administrator
only needs to know address informatio n for that device; the physical
location of the port is irrelevant.
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Use of network resources becomes much more efficient. Each VLAN
can be set up to contain only those devices which need to
communicate with each other. In this way, broadcast storms, the most
common cause of network congestion, can also be avoided.
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Network security is enhanced. Devices within each VLAN can only
communicate with member devices in the same VLAN. If a device in
VLAN 1 for example, needs to communicate with devices in VLAN 2, it
must be configured to cross the router between them.
Further information can be found in
Chapter 4
.
PACE
PACE (Priority Access Control Enabled) technology allows multimedia
applications using voice and video traffic to be carried over standard
Ethernet and Fast Ethernet Local Area Networks (LANs). PACE provides
the quality of service that t hese applications require, reducing latency
to a minimum and prioritizing the multimedia traffic.
Both multimedia and data traffic are improved con siderably by
introducing an Ethernet switch into the LAN and attaching each
end-station to its own dedicated 10Mb ps switch port. This removes any
contention between different end-stations for the Ethernet bandwidth.
However, when two-way traffic is passing between an end-station and
the switch port, access to the bandwidth can still be unfairly allocated
to traffic in one direction, resulting in poor quality vide o display. PACE
allocates the available bandwidth fairly to traffic in each direction. In
this way, existing Ethernet adapters and cabling can be used to run
high-quality multimedia sessions across the LA N.