FAT-Tree Network Topology

A Fat-Tree network topology is a popular and scalable data center design. It's called a "Fat-Tree" because it's fat on every level, which means it has a lot of nodes and redundant paths. High availability and fault tolerance are ensured by this redundancy. A tree-like structure with numerous layers of switches underpins the topology. Let's take a closer look at a Fat-Tree network:

Benefits

Redundancy: Multiple paths between any pair of devices ensure redundancy. If one link or switch fails, there are alternate paths available. Scalability: Fat-Tree networks can be easily scaled by increasing the parameter k and adding more switches and links. Non-blocking: Due to the redundant paths, Fat-Tree networks provide non-blocking, full-bandwidth communication.

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Topology Overview

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A Fat-Tree network is often depicted as a k-ary tree, where k is the number of switch ports. The network is divided into three layers: core, aggregation, and edge. Each switch has k ports.

Core Layer

At the top of the hierarchy are the core switches. There are k core switches in total in a Fat-Tree network. Each core switch is connected to k aggregation switches, forming a full mesh in the core layer.

Aggregation Layer

Below the core layer are the aggregation switches. Each aggregation switch is connected to k/2 core switches and k/2 edge switches. Aggregation switches provide a connection between core and edge switches.

Edge Layer

At the bottom layer are the edge switches. Each edge switch is connected to k/2 aggregation switches and k/2 hosts (servers or devices). Edge switches are directly connected to end devices like servers, providing access to the network.

Hosts

Hosts (servers or end devices) are connected to edge switches. Each edge switch connects to k/2 hosts.

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Connections

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Core Switch Connections

Each core switch is connected to k aggregation switches, forming a full mesh.

Aggregation Switch Connections

Each aggregation switch is connected to k/2 core switches and k/2 edge switches.

Edge Switch Connections

Each edge switch is connected to k/2 aggregation switches and k/2 hosts.

Host Connections

Hosts are connected to edge switches.

Happy Exploring!