A collapsed backbone network, also known as a “flat backbone,” is a type of network topology where all the network segments connect directly to a central device. This central device could be a router, switch, or hub, depending on the design of the network. The term “collapsed” is used because the traditional multi-tiered hierarchy of a network is reduced or “collapsed” into a single tier.

Key Features of a Collapsed Backbone Network:

  1. Single Central Device: In a collapsed backbone design, all devices and segments (like LANs) connect to a single central device.
  2. Simplified Topology: The design is straightforward and is typically easier to manage than more complex hierarchical designs, especially for smaller networks.
  3. Centralized Management: Given that all connections terminate at a single point, network management, troubleshooting, and monitoring become centralized.
  4. Ease of Expansion: Adding additional devices or segments to the network typically involves connecting them to the central device.

Advantages of a Collapsed Backbone Network:

  1. Cost: It can be less expensive than more complex designs because it requires fewer devices and interconnections.
  2. Performance: Since traffic between segments only has to pass through the central device (and not multiple devices), latency can be minimized and performance might be optimized.
  3. Management: With fewer devices and connections to manage, it can simplify network management and troubleshooting.
  4. Scalability: It’s easy to expand the network by adding more connections to the central device.

Disadvantages of a Collapsed Backbone Network:

  1. Single Point of Failure: If the central device fails, all connected segments could lose connectivity.
  2. Bandwidth Limitations: As all traffic flows through a single device, it might become a bottleneck if the network grows too large.
  3. Less Redundancy: Compared to distributed backbone designs which may have multiple paths between segments.

Collapsed backbone designs are particularly common in small to medium-sized organizations or within specific areas of a larger enterprise, like a single building or floor. However, for larger networks spread out over multiple locations, a more distributed or hierarchical backbone design might be preferred to optimize performance and reliability.