In athree-stage IP fabric(also known as a Clos fabric), traffic between any two points (ingress to egress) in the fabric isonly two hops away.
Step-by-Step Breakdown:
* Three-Stage IP Fabric:
* Leaf Layer: Leaf switches connect directly to servers and edge devices.
* Spine Layer: Spine switches provide connectivity between leaf switches but do not connect to each other directly.
* Two-Hop Communication:In this architecture, every leaf switch is connected to every spine switch.
Therefore, when a packet enters the fabric via an ingress leaf switch, it is forwarded to a spine switch, which then directs the packet to the correct egress leaf switch. This path always involves exactly two hops:
* Ingress leaf # Spine # Egress leaf.
* Benefits:This consistent two-hop path ensures predictable latency and makes the network highly scalable while maintaining low complexity.
Juniper Reference:
* IP Fabric Architecture: This two-hop property of Clos fabrics is a hallmark of spine-leaf designs, as supported by Juniper's QFX and EX switches in data centers.