Configuring VLANs 64521Configuring VLANsThis chapter describes how to configure VLANs, including port-basedVLANs, protocol-based VLANs, double-tagged VLANs, subnet-based VLANs,and Voice VLANs.The topics covered in this chapter include:• VLAN Overview• Default VLAN Behavior• Configuring VLANs (Web)• Configuring VLANs (CLI)• VLAN Configuration ExamplesVLAN OverviewBy default, all switchports on a Dell Networking N2000, N3000, and N4000series switches are in the same broadcast domain. This means when one hostconnected to the switch broadcasts traffic, every device connected to theswitch receives that broadcast. All ports in a broadcast domain also forwardmulticast and unknown unicast traffic to the connected host. Large broadcastdomains can result in network congestion, and end users might complain thatthe network is slow. In addition to latency, large broadcast domains are agreater security risk since all hosts receive all broadcasts.Virtual Local Area Networks (VLANs) allow you to divide a broadcast domaininto smaller, logical networks. Like a bridge, a VLAN switch forwards trafficbased on the Layer 2 header, which is fast, and like a router, it partitions thenetwork into logical segments, which provides better administration, security,and management of multicast traffic.Network administrators have many reasons for creating logical divisions, suchas department or project membership. Because VLANs enable logicalgroupings, members do not need to be physically connected to the sameswitch or network segment. Some network administrators use VLANs tosegregate traffic by type so that the time-sensitive traffic, like voice traffic, has
