Category: Software Defined Datacenters

What is Cisco ACI?

Hello World

This is an overview of what I think Cisco ACI actually is. It uses some examples from the lab environment to show you how the things look like when you start to work with ACI. There are other articles in the works which will be online soon and which will go in details through the real configuration of ACI and best practices while doing it.

What is this Cisco ACI Fabric?

Cisco ACI is a datacenter network Fabric. It actually means that it is a networking system of more networking L3 switches that have a modified, next-generation OS which enables them to be centrally provisioned and configured through APIC controller to work as one device from access port perspective.

ACI APIC GUI Topology

The view at Cisco ACI APIC GUI where we see complete ACI Fabric Topology

| Continue Reading.. |

CLOS Topology

Edson Erwin invented this highly scalable and optimized way of connecting network nodes in the 1930s and Charles Clos made the telephone nodes interconnection design using that solution. It was even before we had IP networks. He invented it in order to optimize the architecture of telephony network systems back then.

It was not used in IP based network for last few decades but it experienced a big comeback with new datacenter design in the last few years. It was first invented only for scalability requirements that it solved beautifully. In new datacenter design, CLOS topology of interconnecting network devices scalability is also the first requirement that gets solved, but it also greatly helps with improving resiliency and performance.

In today’s datacenters, CLOS topology is used to create Leaf’n’Spine system of interconnecting Leaf switches (datacenter access switches or ToR switches) together through Spine switches. It is created in a way that each Leaf switch is redundantly connected to all Spine switches directly.

As it is shown in the picture below, in this way, using CLOS topology, we are interconnecting Leaf switches in a way that they always have only two hops between each other and this done redundantly as two hops through each Spine switch. Spines are not directly connected and Leafs are also not directly connected.

CLOS

| Continue Reading.. |