  Due to the requirement of hosting tens of thousands of hosts in today's data
centers, data center networks strive for scalability and high throughput on the
one hand. On the other hand, the cost for networking hardware should be
minimized. Consequently, the number and complexity (e.g. TCAM size) of switches
has to be minimized. These requirements led to network topologies like Clos and
Leaf-Spine networks only requiring a shallow hierarchy of switches---two levels
for Leaf-Spine networks. The drawback of these topologies is that switches at
higher levels like Spine switches need a high port density and, thus, are
expensive and limit the scalability of the network.
  In this paper, we propose a data center network topology based on De Bruijn
graphs completely avoiding a switch hierarchy and implementing a flat network
topology of top-of-rack switches instead. This topology guarantees logarithmic
(short) path length. We show that the required routing logic can be implemented
by standard prefix matching operations in hardware (TCAM) allowing for using
commodity switches without any modification. Moreover, forwarding requires only
a very small number of forwarding table entries, saving costly and
energy-intensive TCAM.
