In this illustration, we first see (from bottom to top) sixteen server racks positioned side-by-side. The first eight of these are numbered and the second eight are not, and the architecture above the first eight is mirrored in the architecture of the second. At the top of each server rack is a TOR switch. The first four switches connect to a second link-layer switch labeled A; switches 5-8 connect to a switch labeled C; the next eight switches similarly connect to two separate switches. These switches are labeled "Tier-2 switches."

Switch A and C connect to switch labeled B. Similarly, the two switches above racks 9-16 connect to a single switch. These switches are labeled "Tier-1 switches." Each tier-1 switch is connected to a server, labeled "Load balancer," as well as to an access router. Both access routers connect to a single router, labeled "Border router." The border router connects to the Internet.