Hack the Route Start free Open app Switches and VLANs
Spine-leaf
A data center design where every leaf (rack) switch connects to every spine, so any two racks are two hops apart.
Servers plug into leaves (top of rack); each leaf has one uplink to every spine, and spines never connect to each other. Any rack reaches any other through any spine, at the same cost, so ECMP (equal-cost multipath) spreads flows over all of them, and adding a spine adds bandwidth. The links are usually routed (BGP or OSPF), with no spanning tree blocking anything. It suits east-west traffic (server to server inside the data center); north-south traffic enters and leaves through border leaves. The older three-tier design (access, distribution, core) suits campus north-south traffic; a collapsed core merges distribution and core for smaller sites.