Network Topology refers to the manner in which nodes on a bus are interconnected.
The most common automotive network configurations are:
- Ring or loop
- Ring-star hybrid
An understanding of the topology of the vehicle network is critical when attempting to diagnose bus communications errors. The topology of the network can provide clues as to how various nodes interact with one another. Topology information is found in vehicle data line wiring schematics.
This diagram illustrates a ring network configuration. PC #1 is connected directly to the server. PC #2 connects to PC#1 and so on. PC #8 completes the ring by connecting directly to the server.
Benefits of the ring configuration include:
In this 2-wire network if one wire fails, communication can continue on the second wire.
The data transmission is amplified as it passes from node to node
In a star configuration, all of the nodes are connected to a central point. This can be a node on the bus, a splice pack, a junction block or simply a hard splice in the wiring. A star configuration is typically found ion a single wire bus.
Benefits of the star configuration include:
- Ease of diagnosis using the spice pack
- All nodes on the bus are connected at one or more junctions
- Easily expandable
The star topology is one of the simplest network configurations and is easily expandable, as additional nodes can simply be plugged into the bus.
Disadvantages of the star configuration include:
- More wiring is necessary to connect each node to the central node
- The star configuration offers no redundancy
- If one wire to a node fails, that node drops off the bus
- If the central node fails, the entire network fails