8 CONFIGURING VLANSVLANs are logical subgroups with a Local Area Network (LAN) whichcombine user stations and network devices into a single unit, regardlessof the physical LAN segment to which they are attached. VLANs allownetwork traffic to flow more efficiently within subgroups. VLANs usesoftware to reduce the amount of time it takes for network changes,additions, and moves to be implemented. VLANs restrict traffic within theVLAN.VLANs have no minimum number of ports, and can be created per unit,per device, or through any other logical connection combination, sincethey are software-based and not defined by physical attributes.VLANs function at Layer 2. Since VLANs isolate traffic within the VLAN, aLayer 3 router working at a protocol level is required to allow traffic flowbetween VLANs. Layer 3 routers identify segments and coordinate withVLANs. VLANs are Broadcast and Multicast domains. Broadcast andMulticast traffic is transmitted only in the VLAN in which the traffic isgenerated.VLAN tagging provides a method of transferring VLAN informationbetween VLAN groups. VLAN1is the default VLAN and always containsuntagged ports. All ports are members of VLAN1 by default. If theuntagged port is moved to a new VLAN, the port is removed fromVLAN1. For example: If an untagged port 24 is moved to VLAN 5. Theport will no longer be a member of VLAN1. However, if the port is addedto VLAN5 as a tagged port it then remains untagged in VLAN1.This section contains the following topics:■ Viewing VLAN Details■ Viewing VLAN Port Details■ Creating VLANs■ Modifying VLAN Settings■ Modifying Port VLAN Settings■ Removing VLANs
