In Data Centers today there is one constant; perpetual change. That one element is what drives the limits of business and the foundational technologies that enable it. In a bold effort to keep pace with this concept of change, a very flexible and efficient Data Center is needed. A Data Center that can support scalable Layer 2 networks needed for high performance computing (HPC), resource pooling, workload flexibility and virtualization.
The truth is that today our Layer 2 domains are severely hampered by fundamental issues associated with their most basic governing element; spanning tree protocol (STP). In an effort to block links thus avoiding the creation of bridging loops STP is in effect limiting our scalability by creating bandwidth restriction. More often than not even the mechanism used by STP to converge can cause application disruption as STP maneuvers around failed links. This means that the typical approach to address this issue in most networks is to deploy smaller layer 2 domains with Layer 3 boundaries, thus affording STP more stability and scalability. This approach of scaling down the layer 2 domain however will not work in the Data Center because virtualization and HPC applications require larger Layer 2 domains in order to maintain server capacity and high availability in the same VLAN. This quandary was addressed with the creation of Cisco FabricPath.
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