A Brief Introduction to Network Bridging Loops In networking, a bridging loop occurs when two network devices have multiple (parallel) paths for communicating with one another. These multiple paths can create a loop over which the network will continually send the same data again and again. Such a bridging loop creates a severe drain that can cause your network to "freeze up" or to become intermittently unreliable. With powerline networking, users may frequently create unintentional bridging loops when connecting the powerline adapters to an existing home network - whether Cat5 cables in the walls, extended wireless networks, or another medium. In general, to avoid bridging loops you should make sure that only ONE of your powerline adapters is connected to the building or wireless LAN. When you plug a powerline adapter into the wall and then the network comes to a standstill, please first verify that you do not have a bridging loop. Below are two simple examples of how users may unintentionally create a bridging loop: Example 1: Bridging loop created over the powerline network and the Cat 5/Cat 6 building LAN Example 2: Bridging loop created over the powerline network and an extended wireless LAN.

The adapter cannot communicate over the existing wiring without power. On the front of the Plaster Networks PLN3 adapter, a green LED indicates that the adapter is receiving power.

 

 

In order to establish a powerline network, the adapters must (a) be able to "hear" one another over the powerline, and (b) share the same network password for sending encrypted data from one unit to the next. A green LED labeled "PL" on the front of the Plaster Networks PLN3 adapter indicates that an adapter is successfully communicating with one or more additional adapters on the powerline.

 

The HomePlug AV technology provides a very robust powerline networking standard. As a result, adapters will be unable to "hear" one another in only the most rare circumstances - for example, communicating across very large buildings.

 

More commonly, adapters aren't able to establish a network connection because they have different network passwords. Plaster Networks provides three different ways to reset the network password for an adapter:

• Press the reset button on the front of each PLN3 adapter: Insert a paper clip in the small hole labeled "RST" and hold for approximately three seconds. The adapter will reset configuration settings to factory default values, including the network password. The default value for the network password is HomePlugAV (the same as the default value for most HomePlug AV adapters from other vendors).
• Use Plaster Networks Service to add (join) a disconnected adapter to the existing powerline network. This process will reset the password of an adapter to match the password on other unit(s) that you have installed. For more information, please see the Plaster Networks Service Tutorial at support.plasternetworks.com.
• Use the PLN3 Administration Console to reset the adapter for one or more adapters in your building using the "Change Network Password of This Adapter" or "Change Network Password of a Different Adapter" commands. You will need to assign a common password to each of the adapters one at a time. For more information, please see the PLN3 User Guide at support.plasternetworks.com.

The LEDs labeled "1" and "2" on the front of the PLN3 adapter indicate that traffic is flowing through the corresponding network ports on the bottom of the unit. If you have an Ethernet cable connected to one of the ports, and if the corresponding LED is not illuminated (either steady or flashing), then the attached device is not communicating with the adapter. Verify that the attached network device is powered on, that the device is enabled for networking, and that the Ethernet cable is securely connected at one end to the appropriate port of the network device and at the other end to the powerline adapter.

Once you have verified that your adapters are communicating over the powerline network (and the PL LED is illuminated on each of the units), you can now view the maximum network throughput enabled between any two adapters. Plaster Networks provides two alternatives for viewing the network throughput.

• Plaster Networks Service offers remote management and configuration of the powerline network through a central site that you may access over the Internet using a standard web browser. One feature of the service provides graphical and tabular views of network throughput across the entire powerline network, so you can easily identify and diagnose underperforming links.
  
  Before logging into the service, first confirm that the adapters are communicating with the server by verifying the "*" LED is illuminated on the front of the PLN3 adapter(s). If the LED is not illuminated, then check to ensure that one (and only one) PLN3 unit is connected to the Internet through your modem/router combination.
  

  

  
  Next, log into the service (you will need to create an account if you have not already done so) and select "Network Status" from the Network Tools menu. Then, click the "Tabular View" link toward the bottom of the page to view performance across the entire network. You will see a table similar to the one below listing all of the adapters in your powerline network, and the throughput in each direction between any two nodes in the network. In this particular example, the network has four adapters installed across the home.
  

  
  
  For the PHY numbers displayed in the example above, a typical broadband connection will require a value of at least 24Mbps to support high definition video and 15Mbps for standard definition video. In many cases, a PHY value of 6Mbps or higher will be sufficient for e-mail and web browsing. In the example above, all of the connections well exceed these minimum levels.
  
  
  
• The PLN3 Administration Console provides another way to view the powerline network throughput to/from a specific adapter. NOTE: To access the console for an adapter, the adapter must be networked to the same router as your PC (over the powerline network, WiFi, or a cabled connection). 
  
  Start by entering the following URL into your browser of choice: PLNXXXXXX.local (where XXXXXX is the PLNID displayed on the top and sides of the PLN3 adapter). Your browser will now display the main menu of the administration console. From this menu, select the "View Network Performance" option to display the network throughput statistics for the adapter.
  

  
  
  

  For the PHY numbers displayed in the example above, a typical broadband connection will require a value of at least 24Mbps to support high definition video and 15Mbps for standard definition video. In many cases, a PHY value of 6Mbps or higher will be sufficient for e-mail and web browsing. In the example above, all of the connections well exceed these minimum levels.