AboutNetworks.net https://aboutnetworks.net Let's talk About Networks, by Jerome Tissieres Wed, 23 Sep 2020 06:25:18 +0000 en-US hourly 1 https://wordpress.org/?v=5.5.1 https://aboutnetworks.net/wp-content/uploads/2018/01/new-logo_router_only_120x120.png AboutNetworks.net https://aboutnetworks.net 32 32 RDMA over Converged Ethernet (RoCE) on Cisco Nexus 9300 https://aboutnetworks.net/rocev2-on-nexus9k/ https://aboutnetworks.net/rocev2-on-nexus9k/#comments Tue, 04 Aug 2020 12:32:19 +0000 https://aboutnetworks.net/?p=3215 On a previous post, I made an introduction about NVMe, NVMe-oF and RDMA for network engineers. In this post, I’m going to talk about RDMA over Converged Ethernet (RoCE) and more specifically how to implement and configure the QoS part of RoCEv2 on the Cisco Nexus 9300 series. What is RoCE? RDMA over Converged Ethernet (RoCE – pronounced “Rocky”) is a network protocol that allows Remote Direct Memory Access (RDMA) over an Ethernet network. It does this by an encapsulation of an InfiniBand transport packet over Ethernet. There are two…

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NVMe, NVMe over Fabrics and RDMA for network engineers https://aboutnetworks.net/nvme-and-nvmeof/ https://aboutnetworks.net/nvme-and-nvmeof/#comments Tue, 04 Aug 2020 12:32:10 +0000 https://aboutnetworks.net/?p=3154 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. Network-based storage (SANs) using NVMe technology –…

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Basic Linux Networking tips and tricks part-4: curl command https://aboutnetworks.net/linux-networking-part-4/ https://aboutnetworks.net/linux-networking-part-4/#comments Fri, 29 May 2020 07:33:59 +0000 https://aboutnetworks.net/?p=3062 Here is another post of the series on basic network troubleshooting and tools under Linux. In this post, I will talk about the cURL command.   Others posts of the series This post is part of a series about basic Linux Networking tips and tricks. The others posts of this series are: The ip and nmcli commands The mtr command The ss and netstat commands The curl command   What is cURL? cURL is a Linux command-line tool for getting or sending data and files, using an URL syntax. Since cURL…

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Automate file uploads to your Cisco Nexus switches https://aboutnetworks.net/automate-file-uploads-nx-os/ https://aboutnetworks.net/automate-file-uploads-nx-os/#comments Tue, 05 May 2020 12:55:54 +0000 https://aboutnetworks.net/?p=3036 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. This script is very simple, it relies only on Netmiko functions and SCP. But it does its job very well and I share it here because it can certainly help you to save time.   What…

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Basic Linux Networking tips and tricks part-3: ss and netstat commands https://aboutnetworks.net/linux-networking-part-3/ https://aboutnetworks.net/linux-networking-part-3/#respond Mon, 04 May 2020 14:55:10 +0000 https://aboutnetworks.net/?p=2633 Here is the third post of the series on basic network troubleshooting and tools under RHEL / CentOS. In this post, I will talk about the netstat and ss commands.   Others posts of the series This post is part of a series about basic Linux Networking tips and tricks. The others posts of this series are: The ip and nmcli commands The mtr command The ss and netstat commands The curl command   netstat The netstat command is a network utility used to display network connections, protocol  or interfaces…

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Cisco Live US 2020: To CLUS or not to CLUS? [updated] https://aboutnetworks.net/to-clus-or-not-to-clus/ https://aboutnetworks.net/to-clus-or-not-to-clus/#respond Tue, 10 Mar 2020 14:43:03 +0000 https://aboutnetworks.net/?p=2702 Update March 16, 2020: The in-person event is “relaunched” as an online event. Here is a copy of the information email I just received: The health and well-being of our customers, partners, employees and communities is of utmost importance to us. As a result, during this unprecedented time of the COVID-19 pandemic, Cisco Live, our premier in-person customer and partner experience of the year, is being relaunched as a complimentary, full-scale digital event, enabling remote participation from anywhere in the world. We’re dedicated to making sure that the experience at…

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Cisco Certifications changes: a short summary https://aboutnetworks.net/new-cisco-certs/ https://aboutnetworks.net/new-cisco-certs/#respond Wed, 26 Feb 2020 01:02:10 +0000 https://aboutnetworks.net/?p=2862 Unless you’ve been living in a cave during the last nine months, specifically since Cisco Live US 2019, you should know that last Monday, February 24th, was the D-day for big changes in Cisco certifications. Here is a short summary of the major changes and what to remember about them. Changes on current certifications Associate level The various CCNA certifications have been consolidated to only one now. And the CCDA also disappears. Remaining certs at associate level are: CCNA DevNet Associate (I will talk about DevNet certs more in details…

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Cisco NX-OS Graceful Insertion and Removal (GIR) https://aboutnetworks.net/cisco-nx-os-graceful-insertion-and-removal-gir/ https://aboutnetworks.net/cisco-nx-os-graceful-insertion-and-removal-gir/#respond Fri, 10 Jan 2020 16:38:20 +0000 https://aboutnetworks.net/?p=2798 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. Scenario Let’s take the example below: (click on the image to see a larger version) We have two Nexus (in nx-os mode) in vPC. Doing layer-2 aggregation and …

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Last year review and resolutions for 2020 https://aboutnetworks.net/2019-review-2020-resolutions/ https://aboutnetworks.net/2019-review-2020-resolutions/#respond Fri, 20 Dec 2019 12:44:29 +0000 https://aboutnetworks.net/?p=2549 As the end of the year approaches, it is time to make a review of the past year and see what I would like to do, what I must do, and what I can improve in 2020. In brief, here’s my last year review and resolutions for 2020. 2019 Review New position This year was really intense for me; not only did I change company, but I also changed my main technology as a network engineer. I went from being a consultant in enterprise networking, doing routing, switching, wireless and…

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Basic Linux Networking tips and tricks part-2: the mtr command https://aboutnetworks.net/linux-networking-part-2/ https://aboutnetworks.net/linux-networking-part-2/#respond Fri, 22 Nov 2019 13:26:55 +0000 https://aboutnetworks.net/?p=2581 Here is the second post of the series on basic network troubleshooting and tools under RHEL / CentOS. In this post, I will talk about the Linux mtr command.   Others posts of the series This post is part of a series about basic Linux Networking tips and tricks. The others posts of this series are: The ip and nmcli commands The mtr command The ss and netstat commands The curl command     Ping and traceroute for basic network troubleshooting We all know the ping and traceroute commands to…

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2019 IT Blog Awards finalist! https://aboutnetworks.net/2019-blog-awards-finalist/ https://aboutnetworks.net/2019-blog-awards-finalist/#respond Thu, 21 Nov 2019 22:56:23 +0000 https://aboutnetworks.net/?p=2652 I have the honor of having my blog selected as a finalist in the Most Educational category of the 2019 IT Blog Awards, hosted by Cisco. Please, click here to vote and choose the winner, voting is open from November 22nd to December 13th. You will find this blog (About Networks) is under the category: Most Educational Thank you in advance for voting and for your support! Did you like this article? Please share it…

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Basic Linux Networking tips and tricks part-1: ip and nmcli commands https://aboutnetworks.net/linux-networking-part-1/ https://aboutnetworks.net/linux-networking-part-1/#comments Fri, 18 Oct 2019 13:03:31 +0000 https://aboutnetworks.net/?p=2568 We have all heard, at one time or another, a system administrator blaming the network. Then, it is up to the network engineers to prove that the network is not in cause. To do this, a minimum of network troubleshooting skills on Linux systems could be required. For the first post in the series: many examples of how to use the ip and nmcli commands.   Others posts of the series This post is part of a series about basic Linux Networking tips and tricks. The others posts of this…

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Cisco Nexus NX-OS tips and tricks https://aboutnetworks.net/cisco-nxos-tips-and-tricks/ https://aboutnetworks.net/cisco-nxos-tips-and-tricks/#comments Fri, 20 Sep 2019 15:17:56 +0000 https://aboutnetworks.net/?p=2458 As you can see here, I have been using Cisco Nexus NX-OS for many years. And even more intensively since a few months, as I work for a data center now. During all this time, I accumulated a nice collection of NX-OS tips and tricks. Here it is. I hope this can help you to improve your daily work. Hexadecimal / Decimal conversion The dec and hex commands can convert hexadecimal to decimal and the inverse. For example: n9k# hex 255 0xff n9k# dec 0x100 256 n9k#   Executing multiple CLI commands in one command Example: n9k# show clock ; show…

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New bookshelf page https://aboutnetworks.net/new-bookshelf-page/ Fri, 26 Jul 2019 10:17:53 +0000 https://aboutnetworks.net/?p=2439 I just created a new bookshelf page to list all the IT / networking / programming books that I have read or I am currently reading. Available here: My Network Engineer Bookshelf   Please, have a look and if you have questions about any of these books, feel free to post a comment. I will answer with pleasure.  

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Shutdown thousands access ports with Python and Netmiko https://aboutnetworks.net/shutdown-thousands-access-ports-with-python-and-netmiko/ https://aboutnetworks.net/shutdown-thousands-access-ports-with-python-and-netmiko/#comments Thu, 23 May 2019 15:49:55 +0000 https://aboutnetworks.net/?p=2370 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. The environment This…

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