I assume you have two networks in your home such as cable and DSL for you and your roommate and you want to use wired networking with access to both networks in common areas with only one Ethernet cable per room. VLANs are a great solution for this. Let's say your roommate needs a connection in the office and one for the downstairs TV for her entertainment device (XBOX, AppleTV, etc), thus you two need to share the Ethernet cable for common rooms. For this scenario, we will split the trunk into a Y configuration, bridging two physically separate cables together with VLAN tagging and trunking sending both LANs to two floors in the home.
|Home Network Carrying multiple VLANs|
We will assign your roommate VLAN7 in the basement distribution switch (switch2), but we'll exclude the Netgear WNDR3800 basement router since which serves the cable modem. In the prior article, you see the basement switch (switch2) as a VLAN distribution point, but it will become a VLAN access point for VLAN7.
Switch 2 changes from the previous build by adding a second trunk to the first floor switch (switch3). Port 3 is now tagged and includes both VLAN1 for the homeowner LAN, and VLAN7 the DSL LAN. Port 2 is assigned to VLAN7's DSL modem which is simulated with a laptop in the video Switch2 doesn't include VLAN7 in the Wan port (W) column excluding it from being able to receive VLAN7 traffic.
|DD-WRT VLAN Trunks and Ports on Linksys e3000|
This is the first floor DD-WRT router using the venerable Linksys WRT54GS router. In this configuration, port 4 is assigned to VLAN7, while the remaining ports stay on VLAN1 except for the WAN port which is the trunk line from the basement. This router supports the roommate's living room device on port 4. The video uses my receiver to simulate the roommate's device.
|Linksys WRT54GS VLAN Trunk|
Electric wiring or wireless technologies can also be used to connect different networks to devices around the home and these solutions tend to be the the star attraction when you inquire at places like Micro Center or Best Buy for help, but you have another very powerful technique in VLANs which can be used with the inexpensive equipment you or others have discarded. You can also find many managed switches under $100 U.S. if you wish to purchase hardware dedicated to VLAN networks.