Accton Technology VS4512DC Management Manual page 18

Introduction
Virtual LANs – The switch supports up to 255 VLANs. A Virtual LAN is a collection
of network nodes that share the same collision domain regardless of their physical
location or connection point in the network. The switch supports tagged VLANs
based on the IEEE 802.1Q standard. Members of VLAN groups can be manually
assigned to a specific set of VLANs. This allows the switch to restrict traffic to the
VLAN groups to which a user has been assigned. By segmenting your network into
VLANs, you can:
• Eliminate broadcast storms which severely degrade performance in a flat network.
• Simplify network management for node changes/moves by remotely configuring
VLAN membership for any port, rather than having to manually change the network
connection.
• Provide data security by restricting all traffic to the originating VLAN.
• Use private VLANs to restrict traffic to pass only between data ports and the uplink
ports, thereby isolating adjacent ports within the same VLAN, and allowing you to
limit the total number of VLANs that need to be configured.
Traffic Prioritization – This switch prioritizes each packet based on the required
level of service, using four priority queues with strict or Weighted Round Robin
Queuing. It uses IEEE 802.1p and 802.1Q tags to prioritize incoming traffic based on
input from the end-station application. These functions can be used to provide
independent priorities for delay-sensitive data and best-effort data.
This switch also supports several common methods of prioritizing layer 3/4 traffic to
meet application requirements. Traffic can be prioritized based on the priority bits in
the IP frame's Type of Service (ToS) octet. When these services are enabled, the
priorities are mapped to a Class of Service value by the switch, and the traffic then
sent to the corresponding output queue.
Multicast Filtering – Specific multicast traffic can be assigned to its own VLAN to
ensure that it does not interfere with normal network traffic and to guarantee
real-time delivery by setting the required priority level for the designated VLAN. The
switch uses IGMP Snooping and Query to manage multicast group registration.
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