How to Build a Bus Network

A bus network is defined as one in which systems interconnect using a common media pathway with equal rights to that pathway. This article looks at how to deploy an inexpensive bus network and identifies some advantages in doing so.

Things You'll Need

• Two or more Ethernet computers
• Wi-Fi or
• Ethernet hub and Unshielded Twisted Pair (UTP) Ethernet cables

Instructions

Common Access

1. Select your interconnect.
   Because the principle behind a bus network is common access among peers with equal rights to the medium, an Ethernet hub is the most typical means of creating a bus topology for a local area network (LAN). A wireless network, however, may also be considered a bus architecture, as all the clients on a wireless network, may send and receive without limitation to the medium.

2. Plug in--wired.
   In the typical wired LAN, each client computer plugs an Unshielded Twisted Pair cable into the Ethernet connection of her computer, and into a network hub port as well. In office settings, the physical connection from the client computer may well be to a faceplate in a wall, but the cables running through the walls are likely to terminate in a centralized wiring closet or computer room with a network hub or switch as a final destination.

3. Plug in--wireless.
   Though there aren't wires in a wireless connection, there is still the notion of "plugging in." Of all the potential wireless communications targets in the area, you must select one your computer will elect to converse with. By joining or selecting a given Wi-Fi network, you are plugging effectively into the wireless hub for that virtual LAN.

4. 

   Test your success.
   Is your network really a bus topology? It's not complicated to test. One key feature of a bus topology is the idea that the transmission medium is common to all the systems on it. This means that when one system "speaks," all the others hear the message. Whether they pay attention or not is a different issue, but all should hear the message. To test, fire up a protocol analyzer on one of the systems, then see if traffic for other systems can be seen going by on the network.

5. 

   Consider alternatives.
   A bus network is typically lower cost than some alternatives, but the fact that all systems see all the traffic for one another may drive you to consider alternatives. A switched network isolates traffic between systems such that messages are only seen by systems specifically targeted. If Systems A, B, and C are all on a switched network, System C will not physically receive packets System A sends to System B. This can have some performance and security benefits and is at least nominally more expensive as a result.

Tips & Warnings

• It may or may not be desirable to have all systems connected able to witness the packet traffic of their peers. Consider the potential security implications of a bus network topology.

Resources

• Advantages and Disadvantages of Ethernet Hubs and Switches