Isolated Forwarding Strategy in Metro Ethernet Networks

The Spanning Tree Protocol (STP) is an approved standard that provides a loop-free active topology in Ethernet networks. The main idea in the STP is reducing the topology of a network to a tree topology by blocking the redundant ports. The lack of any traffic engineering mechanism for load balancing in the STP results in uneven traffic distribution and bottlenecks near the Root. This protocol causes a severe penalty on the performance of Metro Ethernet Networks, since it makes inefficient use of the links and switches. In our previous work, we proposed the Shortcut Switching Strategy (SSS) that uses some blocked ports to improve the load balancing and performance of the standard STP. In this paper, we propose a novel forwarding strategy named the Isolated Forwarding Strategy (IFS) that also uses blocked ports to forward frames but in a more sophisticated manner than SSS. In other words, the IFS is an extended version of the SSS. The IFS in comparison to the STP and SSS, decreases the average traffic load on links and switches, improves load balancing and reduces the average number of switching hops. We will show these improvements by using analytical and simulation methods.