1 Version 3.0 Module 8 Virtual LANs

2 Version 3.0

3 What is a Virtual LAN (VLAN)? Logical grouping not dependent on physical location Operate at layer 2 & 3 VLANS do not forward broadcasts

4 Version 3.0 TO IMPLEMENT VLANS: 1.PORT-CENTRIC make port 1 VLAN 1, port 2 VLAN 2, etc. Easier to administer, easier to set-up not secure cause you can physically move cable EACH VLAN IS A SEPARATE BROADCAST DOMAIN 2.DYNAMIC VLANS based on intelligent mgmt. Software more work up front admin has to type in addresses based on MAC, logical addr., or protocol type even w/ a hub on 1 port w/ workstations, they are all on 1 VLAN

5 Version 3.0 VLANS SWITCHES ARE CORE COMPONENT OF VLANS VLANS can’t talk to each other, have to use router

6 Version 3.0 VLAN Configuration and Topology Trend: Growing use of switches and virtual LANs (VLANs) VLANs require switches that have Layer 3 (IP) addressing capabilities

7 Version 3.0 What Is a Virtual LAN (VLAN)? Logical networks independent of their members’ physical location Administratively defined broadcast domain Users reassigned to different VLAN using software Administration Engineering Marketing

8 Version 3.0 VLAN Benefits Reduces administration costs Manages broadcast domain sizes Offers security because routers provide communication and firewalls between VLAN groups Logical groupings of users VLAN Group 1 VLAN Group 2

Switches and routers each play an important role in VLAN design. Switches are the core device that controls individual VLANs while routers provide interVLAN communication

10 Version 3.0 The Role of the Router in VLANS Policy-based control Broadcast management Route processing & distribution Provide the communication between VLANs. Provide VLAN access to shared resources, such as servers & hosts.

11 Version 3.0 Benefits of VLANs Create broadcast domains Control network traffic Increased security Workstations can be moved without needing reconfiguration

12 Version 3.0 VLAN Membership Port based MAC addressed based Protocol based Any VLAN is a layer 3 broadcast domain VLAN traffic between switches (trunks) is tagged (802.1q) or encapsulated (ISL) to identify VLAN membership

13 Version 3.0 VLAN IOS Configuration Example Switch#vlan database Switch(vlan)#vlan 2 Switch(vlan)#name marketing Switch(vlan)#exit Switch(config)#interface fastethernet 0/9 Switch(config-if)#switchport mode access Switch(config-if)#switchport access vlan 2

14 Version 3.0 Other VLAN/Switching Commands Switch#show vlan Switch#show vlan brief Switch#show spanning-tree Switch#Show interface

15 Version 3.0 Module 8 Virtual LANs END