VLAN benefits

• Traveling Users
– 20% to 40% of work force moves every year
• net admin’s biggest headache
• largest expense in managing networks. Moves may require...
– recabling
– readdressing and reconfiguration
– VLANs provide a way to control these costs. As long as the user still
belongs to the same VLAN...
• simply configure the new switch port to that VLAN
• router configuration remains intact
– Routers provide an effective firewall against broadcasts
– Adding VLANs can extend a router’s firewall capabilities to the “switch
– The smaller the VLAN, the smaller the number of users that are effected
by broadcasts
– Shared LANs are easy to penetrate...simply plug into the shared hub.
– VLANs increase security by ...
• restricting number of users in a VLAN
• preventing user access without authorization
• configuring all unused ports to the “Disabled” setting
• control access by
– addresses
– application types
– protocol types
• Hub Replacement & Segmentation
– The ports on a non-intelligent hub can only be assigned one VLAN.
– Replacing hubs with switches is relatively cheap compared to the benefit
– In the graphic, replacing the core hub in an extended star topology with a
VLAN capable switch effectively microsegments one shared LAN into six.