It's very common to see rack mount servers and storage wired to a fabric consisting of multiple tiers of switches all racked together in another part of the data center. Performance bottlenecks due to blocking is accepted as are large bundles of cables streaming through the floor or across the ceiling from each rack. Most data center administrators realized long ago they could not continue to scale up their capacity with blocking fabrics and if it meant a lot more cables through the floor or across the ceiling.
Many data center managers are solving these problems and lowering their costs by migrating to a two-tier network architecture consisting of top-of-rack switches and core switches.
There are still dense bundles of cables from the servers and storage to a top-of-rack switch or two, but the cabling mess is confined to the rack. And you get the throughput needed from a rack to a core switch with just a few cables for high bandwidth10-Gbps Ethernet.
What's needed at the core of two-tier network architectures are highly-scalable, non-blocking, 10-Gbps Converged Enhanced Ethernet (CEE) layer 2 switches. These capabilities in an Ethernet fabric allow data center administrators to interconnect huge server farms heavily loaded with virtual machines. They also provide the lossless IP-based SAN connectivity needed to support the massive aggregation of I/O created by these dense compute nodes.
Vendors are seizing the opportunity to cash in on these trends with products built from the ground up for scale-out in a two-tier network. A great example is the Vantage 8500, a 10 Gigabit Ethernet high-performance, high density, Layer 2 core switch just announced by Voltaire. The Voltaire Vantage 8500 features 288 wire-speed, 10-Gigabit Ethernet ports in a 15U high chassis. Voltaire claims it is the world's largest non-blocking Ethernet data center switch. The switch features a unique scale-out stacking option enabling more than 3,400 non-blocking ports in a single switching fabric. The Vantage 8500 is based on CEE technology to provide InfiniBand-like capabilities to the data center such as a lossless switching fabric, multi-pathing, virtualization, fabric-wide congestion management and QoS.
