8 And Switch

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Traditional LANs are defined by location. Virtual LANs, on the other hand, are not constrained by any geographic or physical limitations. While a LAN may make sense for small networks, it makes expansion or reorganization difficult. Under a LAN setup, all the devices and equipment are located physically near each other and directly connected to a router, which is why a physically disjointed organization can't use a single network address space. To put those users on the same broadcast domain, the organization needs a VLAN.

The Test Center redefined an existing LAN to take advantage of VLANs for bandwidth and security purposes. The network, designed to approximate the kind of environment found in small businesses, consisted of several servers, desktops and laptops, all running either Microsoft Windows XP, Windows Vista or Debian Linux. The LAN included both wired and wireless networks. For this VLAN setup, Test Center staff used the NetGear Inc. Prosafe 48-Port Gigabit Stackable Smart Switch GS748TS. Here's how it should go:

Step 1: Design the VLAN on paper and assign ports
For this step, Test Center staff conceptually laid out exactly what the network would consist of. Depending on usage, number of users and type of devices, the network design can vary in its level of complexity. For this setup, staff identified four different groups: the broadband connection, the wired network, wireless connectivity and an isolated testing network.

With the various groups identified, staff divided up the ports and assigned them to each group. To allow traffic to pass from one group to the other, or access the Internet, the broadband router had to be connected to a port that was a member of all of the VLANs. Port 1 was set aside to be part of VLAN1, VLAN2, VLAN3 and VLAN4 since that is where routers would go. Ports 2 to 7 also would be part of VLAN2 for other sources of broadband. The bulk of the ports, from ports 8 to 36, were allocated for the internal wired network, VLAN1. The wireless VLAN3 had ports 37 to 42. And finally, the design assigned VLAN4, the testing network, to ports 43 to 48.

Step 2: Set up the switch
Test Center staff plugged a laptop directly into the switch and powered up both the switch and the laptop. Both the NetGear Smart Wizard Discovery program and the Web browser interface can be used to configure the switch. The Smart Wizard Discovery program can find all the switches on the network without using the IP address. The Web browser interface can be accessed from any location via the switch's IP address, supports password protection and allows more extensive configuration and backup of the settings. The switch has been preconfigured from the manufacturer with a default IP address of 192.168.0.239 and subnet mask of 255.255.255.0.

A static and valid IP address can be manually assigned to the switch using the Smart Wizard Discovery program. For networks with DHCP, the program can "discover" the switch and have the DHCP assign a dynamic address. After the switch has received a new address, clicking on Web Access from the program opens up the browser-based interface.

Test Center staff manually configured the laptop to be on the switch's default subnet and opened up the Web configuration tool. Changing the machine's subnet is necessary to access the Web configuration tool without using the Smart Wizard Discovery program. The default password is "password."

At this point, a better IP address that fits the rest of the network can be assigned. If a static address has already been assigned, there's no need to put in a new IP address. For security reasons, staff changed the password to the Web-based configuration.

Step 3: Create VLANs
From the Web tool, there's a section in the left pane for VLAN. Click on Properties to open the VLAN Properties Page. All existing VLANs, the ID, name and type are listed in a table. There's also the option for deleting VLANs. Clicking on the button marked Add opens the Add VLAN Page where a number (for the ID) and a name (any text) is entered to create a new VLAN. This is done three times to create VLAN2, VLAN3 and VLAN4. VLAN1 comes in default.

Next: Step 4: Assign the ports

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