3.1 VLAN Segmentation: VLANs (CCNA 2: Chapter 3) HD

Explain the purpose of VLANs in a switched network. Analyze how a switch forwards frames-based on VLAN configuration in a multi-switched environment. Configure a switch port to be assigned to a VLAN based on requirements. Configure a trunk port on a LAN switch. Configure Dynamic Trunk Protocol (DTP). Troubleshoot VLAN and trunk configurations in a switched network. Configure security features to mitigate attacks in a VLAN-segmented environment. Explain security best practices for a VLAN-segmented environment. One of the technologies used to improve network performance is the separation of large broadcast domains into smaller ones. Routers will, by default, accomplish this by blocking broadcast traffic at an interface. A VLAN is a logical partition of a Layer 2 network. The role of providing access into a LAN is normally reserved for an access layer switch. A VLAN can be created on a Layer 2 switch to reduce the size of broadcast domains, similar to that of a Layer 3 device. While VLANs are primarily used within switched local area networks, modern implementations of VLANs allow them to span MANs and WANs. Spanning VLANs is a method of connecting geographically distinct offices within an organization. This chapter describes how to configure, manage, and troubleshoot VLANs and VLAN trunks. This chapter also examines security considerations and strategies relating to VLANs and trunks, and best practices for VLAN design.