The deployment of physical redundancy is the simplest way to establish stable and uninterrupted communication between devices within an enterprise network. It is crucial to ensure that a network is reliable, performs well, and can recover quickly from failures or disasters such as a fire or a flood.
Physical redundancy in a network refers to the practice of duplicating network components such as switches, routers, and cables. This ensures that if one component fails, another can seamlessly take over the network's operation, minimizing downtime and maintaining network availability.
As such, redundancy plays an essential role in network design, particularly for critical applications that require high availability and reliability, such as real-time voice and video services.
It also improves network performance by reducing the traffic that any single component has to handle. This helps to prevent bottlenecks and congestion on the network, leading to faster data transfer speeds and better overall performance.
For example, if a network uses a single router to connect to the internet, a failure of that router could lead to a complete network outage. However, if the network includes a redundant router that can take over in case of a failure, the network can continue to operate without interruption.
The Drawback of Physical Redundancy
While physical redundancy increases network reliability and availability, it can also create loops in the network. This usually happens when physical redundancy is implemented without proper configuration or management. A loop occurs when there are multiple paths between two devices, and data packets are forwarded between them endlessly, resulting in a switching loop.
For example, consider the network in the image above, where three switches are connected to provide redundancy. If all links are active simultaneously without proper configuration, the switches will forward packets in a loop between each other, causing a broadcast storm and eventually crashing the network.
The same applies in the case of two switches connected using two physical links to provide link redundancy. It will result in a switching loop. Once created, the loops lead to network instability, decreased functionality, and increased overhead. Over time, these loops make the network slow, idle, or even non-functional.