Allied Telesis AT-GS950/8 manual VLAN Features

Chapter 6: VLANs

VLAN Features

Increased Performance

Improved Manageability

Increased

Security

A Virtual Local Area Network (VLAN) is a logical grouping of devices on different physical LAN segments that allows users to communicate as if they were physically connected to a single LAN, independent of the physical configuration of the network.

With VLANs, you can segment your network and group end-nodes with related functions into their own separate, logical LAN segments. For example, the marketing personnel in your company may be spread throughout a building. Assigning marketing to a single VLAN allows marketing personnel to share resources and bandwidth as if they were connected to the same segment. The resources of other departments can be visible to the marketing VLAN members, accessible, or accessible only to specified individuals.

A few benefits of a VLAN architecture are described in the following sections.

In traditional Layer 2 switched networks, broadcast packets are sent to each and every individual port. Grouping users into logical networks limits broadcast traffic to users performing similar functions or users within individual workgroups. High traffic, the danger of broadcast storms, router latency, and data collisions are significantly reduced, and the efficiency of the entire network is improved.

VLANs provide a fundamental improvement in the design, administration, and management of LANs. Before VLANs, physical changes to a network were made at the switch in the wiring closet.

For example, if an employee transferred to a new department, changing that employee’s LAN segment assignment often required a physical wiring change at the switch.

As a software-base solution, VLANs eliminate the restriction of existing network design and cabling infrastructure and allow the centralized configuration of switches located in many different locations. VLAN memberships are changed quickly and efficiently from the management console rather than in a wiring closet.

VLANs provide additional security not available in a shared media network environment. Because a switched network only delivers frames to intended recipients, and only broadcast frames to other members of the VLAN, a network administrator can segment users requiring access to sensitive information into separate VLANs from the rest of the general user community.

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