Migrating Cisco FabricPath and Classic Ethernet Environments to VXLAN BGP/EVPN over a 400Gb-based Clos Topology, part 1 – the why

During the past three years, I have spent a good portion of my time testing, planning, designing, and then migrating our DC network from Cisco FabricPath and Classic Ethernet environments to VXLAN BGP/EVPN. And simultaneously, from a hierarchical classic two-tier architecture to a more modern Clos 400Gb-based topology. The migration is not yet 100% completed, but it is well underway. And I have gained significant experience on the subject, so I think it’s time to share my knowledge and experiments with our community.

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Cisco DCAUTO exam study resources

I just passed the Cisco DevNet DCAUTO (300-635) exam (Yay!). This is my 3rd Cisco exam on network automation after NPDESI in 2018 (replaced now by the DevNet program), and DevNet CORE (DEVCOR) in 2020. But this time, I documented everything I read, so I could report it here and build a Cisco DCAUTO exam study resources. By doing this, I hope to help anyone who wants to study for this certification. And, as I have already passed the DevNet CORE exam, I am now Cisco certified DevNet Professional.

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How to simulate a host in a real network?

Like some other posts, I didn’t think I would write this one because it seemed obvious. But, after talking to a lot of engineers and customers, I realized that not everyone knows this trick. So here it is. The question is this: how to simulate a real host in a physical network environment when you don’t have computer at your disposal? Well, let’s take an example.

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NVMe, NVMe over Fabrics and RDMA for network engineers

In the past, the evolution of network-based storage was not really a problem for network engineers: the network was fast and the spinning hard drives were slow. Natural network upgrades to 10Gb, 40Gb, and 100Gb Ethernet were more than sufficient to meet the networking needs of storage systems. But now, with the introduction of ultra-fast solid-state disks (SSDs) and Non-Volatile Memory Express (NVMe), this is no longer true! Storage teams now have the ability to potentially saturate the network with incredibly fast devices.

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Automate file uploads to your Cisco Nexus switches

If you have more than three Cisco Nexus switches in nx-os mode, and you are not using Cisco DCNM or any other similar tool, you probably already have encountered this question: How to automate file uploads to your Cisco Nexus switches? Here is a turnkey Python script using Netmiko’s SCP function to do this.

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Cisco NX-OS Graceful Insertion and Removal (GIR)

If you operate a data-center network with Cisco Nexus, you’ve probably already faced the problem of how to perform a maintenance on one of the two switches of a vPC pair, with minimum impact and risks for the production network. Cisco NX-OS contains a feature called “Graceful Insertion and Removal” or GIR to help you for that. Here is how it works.

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Shutdown thousands access ports with Python and Netmiko

When people ask me “what a network engineer should do to start in network automation?”, my first answer is: start with small things. Try to automate basic and repetitive tasks you do every day. Go after the low-hanging fruits first. Then, step by step, you can do more and more complex things. This is how I learn the best. In the same vein, I want to share with you my recent experience of automating a very basic and repetitive task: shutdown thousands of unused network access ports.

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100Gb Ethernet transceivers, modules and form factors on Cisco products

At the time of the 400Gb Ethernet interfaces introduction, here is a summary of the different form-factors, transceivers and modules available for 100Gb Ethernet on Cisco devices. As you will see below, there are many different types of 100Gb Ethernet transceivers. And each type have its own functional mode. In a next article, I will try to explain the differences between them and will give more details about the most common: the QSFP-28.

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