Conventional Core; Distributed Core - Dell Active Fabric Manager Deployment Manual

Conventional Core

A conventional core is a three-tier network that is typically chassis based and is composed of the following:
• Core — The core layer routes traffic to and from the internet and the extranet. Redundancy and resiliency are
the main factors for high availability, which requires chassis-based core routers.
• Aggregation layer — The aggregation layer connects with top of rack (ToR) switches and aggregates the traffic
into fewer high-density interfaces such as 10GbE or 40GbE. This layer aggregates the traffic to the core layer.
• Access layer (ToR) — The access layer typically contains ToRs. A ToR is a small form-factor switch that sits on
top of the rack and allows all the servers in the rack to be cabled into the switch. A ToR has a small 1 to 2 rack
unit (RU) form factor.

Distributed Core

A distributed core is a two-tier architecture composed of multiple switches interconnected to provide a scalable, high-
performance network that replaces the traditional and aggregation layers in a conventional core. Switches are
arranged as spines and leaves; the spines interlink (connect) the leaves together using a routing protocol. The leaves'
edge ports connect to the switches, ToR switches, servers, other devices, and the WAN. The spines move traffic
between the leaves bi-directionally, providing redundancy and load balancing. Together, the spine and leaf architecture
forms the distribute core fabric.
This two-tier network design allows traffic to move more efficiently in the core at a higher bandwidth with lower
latencies than most traditional three-tier networks. Because there is no single point of failure that can disrupt the entire
fabric, the distributed core architecture is more resilient and as a result, there is less negative impact on the network
when there is a link or node failure. The AFM views the distributed core as one logical switch.
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