VLANs

Access Ports

Sections: 

Overview: 

  • An access port is a port on a switch that is assigned to a single VLAN or logical subnet that are used by connected endpoints of that port 
  • By default all ports on a switch are assigned to VLAN 1 where each VLAN is segmented into it's own broadcast domain 
  • There are two ranges of VLANs that can be used and defined on a Cisco switch 
    • Standard VLAN Range: 1-1005
    • Extended VLAN Range: 1006-4094
  • When a switchport belongs to a VLAN, the switch learns and manages the addresses associated with the port on a per-VLAN basis
  • It's important to note that end devices assigned to a VLAN on a switchport have no understanding of the VLAN concept and is therefore strictly a network layer concept that are managed by switches and routers/firewalls 

Lab Topology

Scenario:

  • In this lab topology scenario we will configure the specified VLANs on all switches
  • When all VLANs are configured, next step would be to assign the correct interfaces of HQ-Access-SW1 and HQ-Core-SW1 in their respective VLAN tag

VLAN Configuration

HQ-Access-SW1 

HQ-Distro-SW1

HQ-Distro-SW2

HQ-Core-SW1

To summarize the VLAN configuration scenario, the same 4 VLANs have been defined and named on all 4 switches

  • Global Configuration Commands
    • To define a VLAN 
      • vlan <vlanID> 
    • To name a VLAN
      • name <descriptive-name>
    • To verify defined VLANs
      • show vlan brief

Interface VLAN Assignment

Scenario:

  • Up to this point we have defined the 4 VLANs on the 4 switches within the lab topology
  • Next step would be to assign the appropriate interfaces a VLAN tag for the connected devices off of HQ-Access-SW1 and HQ-Core-SW1

HQ-Access-SW1 

HQ-Core-SW1

To summarize the scenario, the interfaces Gi3/1, Gi3/2, and Gi3/3 of the access switch have been assigned to their respective VLAN in addition to interface Gi1/1 of the core switch

  • Interface Configuration Commands
    • To assign interface to a VLAN
      • switchport access vlan <vlanID>