ZyXEL Communications ES-4024A manual Vlan Overview

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ES-4024A Series Switch Support Notes

Separating a physical network into many virtual networks

What is Virtual LAN?

•VLAN Overview

A VLAN (Virtual Local Area Network) allows a physical network to be partitioned into multiple logical networks. Stations on a logical network belong to one group called VLAN Group. A station can belong to more than one group. The stations on the same VLAN group can communicate with each other. With VLAN, a station cannot directly talk to or hear from stations that are not in the same VLAN group(s); the traffic must first go through a router.

In MTU or IP-DSLAM applications, VLAN is vital in providing isolation and security among the subscribers. When properly configured, VLAN prevents one subscriber from accessing the network resources of another on the same LAN, thus a user will not see the printers and hard disks of another user in the same building.

VLAN also increases network performance by limiting broadcasts to a smaller and more manageable logical broadcast domain. A VLAN group is a broadcast domain. In traditional Layer-2 switched environments, all broadcast packets go to each and every individual port. With VLAN, all broadcasts are confined to a specific broadcast domain.

There are two most popular VLAN implementations, Port-based VLAN and IEEE 802.1q Tagged VLAN. ES-4024A series supports both VLAN implementations. The most difference between both VLAN implementations is Tagged VLAN can across Layer-2 switch but Port-based VLAN cannot.

•Port-based VLAN

Port-based VLANs are VLANs where the packet forwarding decision is based on the destination MAC address and its associated port.

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