D-Link DWS-3227P - xStack Switch - Stackable Bedienungsanleitung PDF herunterladen (Seite 7)

Semaphore Technologies Pvt. Ltd. – (technolo[email protected]om)

Link aggregation allows you to use multiple ports for the same connection achieving

higher data transfer speeds. Creating VLANs can serve security and performance

goals by reducing the size of the broadcast domain.

Virtual LAN

A virtual LAN, commonly known as a VLAN, is a group of hosts with a common set

of requirements that communicate as if they were attached to the same wire,

regardless of their physical location. A VLAN has the same attributes as a physical

LAN, but it allows for end stations to be grouped together even if they are not

located on the same LAN segment. Network reconfiguration can be done through

software instead of physically relocating devices.

A VLAN can be thought of as a broadcast domain that exists within a defined set of

switches. Ports on a switch can be grouped into VLANs in order to limit traffic

flooding since it is limited to ports belonging to that VLAN and its trunk ports. Any

switch port can belong to a VLAN. Packets are forwarded and flooded only to stations

in the same VLAN. Each VLAN is a logical network, and packets destined for stations

that do not belong to the same VLAN must be forwarded through a routing device.

Each VLAN can also run a separate instance of the spanning-tree protocol (STP).

Cisco switches support an independent implementation of STP for each VLAN by

using per-VLAN spanning tree (PVST).

VLANs are created to provide the segmentation services traditionally provided by

routers in LAN configurations. VLANs address issues such as scalability, security, and

network management. Routers in VLAN topologies provide broadcast filtering,

security, address summarization, and traffic flow management. By definition,

switches may not bridge IP traffic between VLANs as it would violate the integrity of

the VLAN broadcast domain.

Virtual LANs are essentially Layer 2 constructs, whereas IP subnets are Layer 3

constructs. In a campus LAN employing VLANs, a one-to-one relationship often exists

between VLANs and IP subnets. Although it is possible to have multiple subnets on

one VLAN or have one subnet spread across multiple VLANs. Virtual LANs and IP

subnets provide an independent Layer 2 and Layer 3 constructs that map to one

another and this correspondence is useful during the network design process.

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D-Link DWS-3227P - xStack Switch - Stackable Bedienungsanleitung Seite 7