Collapsed Core Cisco Architecture

The Collapsed Core Cisco Architecture, also called the Two-Tier Architecture, is a network design model commonly used for small to medium-sized enterprise networks.

It simplifies the network structure by reducing the number of layers compared to the traditional Three-Tier Architecture.

Here's what a typical Collapsed Core Cisco network looks like;

Figure 1 – Collapsed Core: Core and Distribution merged into one layer

As you can see the Collapsed Core Architecture is made up of two layers:

• Collapsed Core Layer

• Access Layer

To help you understand this architecture, let’s compare it to a traditional three-layer design:

Figure 2 – Comparison between Three-Tier and Collapsed Core designs

• On the left: Three-Tier Architecture separates the network into Core, Distribution, and Access layers.

• On the right: Collapsed Core Cisco Architecture combines the Core and Distribution layers into a single layer.

This new design reduces the number of layers, simplifying the network.

This leads to an important question:

It’s a good question, let’s break it down together !

The Collapsed Core Cisco Architecture offers several key advantages, but it also has some limitations that you need to consider:

When is Collapsed Core Architecture a good choice ?

This kind of design is perfect for:

• Small and medium-sized businesses that don’t expect massive network growth.

• Simple campus networks with a limited number of users and devices.

• Organizations on a tighter budget that want solid performance without overspending.

In short: if you want a network that’s easy to build, affordable and manageable, the Collapsed Core Cisco Architecture is a great fit.

Now that you have the big picture, let’s dive into the details, starting with the Access Layer.

If you’ve already heard about the Access Layer in the Three-Tier Architecture, you’ll find it’s pretty much the same here.