Inside Flat Networks

Virtualization causes significant changes in network traffic, forcing IT to reconsider the traditional three-tier network approach. Tiered networks were designed to route traffic flows from the edge of the network through the core and back, which introduces choke points and delays while providing only rudimentary redundancy.

Enter the flat network. Also called a fabric, this approach allows for more paths through the network and is better suited to the data center's requirements, including the need to support virtualized networking and virtual machine mobility. A flat network aims to minimize delay and maximize available bandwidth while providing the multitude of network paths demanded in a virtual world.

But a flat network also requires some trade-offs, including the need to rearchitect your data center LAN and adopt either new standards such as TRILL (Transparent Interconnection of Lots of Links) and SPB (Shortest Path Bridging) or proprietary, vendor-specific approaches. We'll look at how a flat network differs from a traditional tiered infrastructure and examine potential shortcomings. (For a look at flat network security, see "How To Secure Your Flat Network".)

How We Got Here

Ethernet won the battle for the LAN more than a decade ago, but it still suffers significant limitations. One prominent problem is the forwarding mechanism. When an Ethernet switch doesn't ...