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Category Archives for "ipSpace.net"

Smart NICs with Silvano Gai on Software Gone Wild

A while ago we discussed a software-focused view of Network Interface Cards (NICs) with Luke Gorrie, and a hardware-focused view of them with Or Gerlitz (Mellanox), Andy Gospodarek (Broadcom) and Jiri Pirko (Mellanox).

Why would anyone want to implement features in hardware and not in software, and what would be the best hardware implementation? We discussed these dilemmas with Silvano Gai in Episode 110 of Software Gone Wild podcast.

Feedback from Another SD-WAN Fan

I don’t know what’s wrong with me, but I rarely get emails along the lines of “I deployed SD-WAN and it was the best thing we did in the last decade” (trust me, I would publish those if they’d come from a semi-trusted source).

What I usually get are sad experiences from people being exposed to vendor brainwashing or deployments that failed to meet expectations (but according to Systems Engineering Director working for an aggressive SD-WAN vendor that’s just because they didn’t do their research, and thus did everything wrong).

Here’s another story coming from Adrian Giacometti.

Do We Need Bare Metal Servers in Public and Private Clouds?

Whenever I was comparing VMware NSX and Cisco ACI a few years ago (in late 2010s in case you’re reading this in a far-away future), someone would inevitably ask “and how would you connect a bare metal server to a VMware NSX environment?

While NSX-T has that capability since release 2.5 (more about that in a later blog post), let’s start with the big question: why would you need to?

Feedback: How Networks Really Work

In early April 2020 I ran another live session in my How Networks Really Work webinar. It was supposed to be an easy one, explaining the concepts of packet forwarding and routing protocols… but of course I decided to cover most solutions we’ve encountered in the last 50 years, ranging from Virtual Circuits and Source Route Bridging to Segment Routing (which, when you think about it, is just slightly better SRB over IPv6), so I never got to routing protocols.

That webinar was supposed to be an introductory one, but of course I got pulled down all sorts of rabbit trails, and even as I was explaining interesting stuff I realized a beginner would have a really hard time following along… but then I silently gave up. Obviously I’m not meant to create introduction-to-something material.

What If… There Would Be an Easy Way to Run Your Network

Imagine a life where you would be able to…

  • Find all interfaces that have VRRP configured but no useful VRRP neighbor;
  • Find all OSPF adjacencies that should be up but are not;
  • Get an alert every time the default IP route is lost;
  • Find all MTU mismatches in your network;
  • List all VXLAN-to-VLAN mappings across your data center, and find if two different VLANs map into the same VXLAN VNI;
  • Compare IP routes in your data center to those you had yesterday;
  • Verify that IP routing tables on all spine switches contain the same prefixes;
  • Do the same comparison before and after a software upgrade;
  • Identify changes in IP routing tables or ARP tables that happened between yesterday evening and this morning;

… and be able to do all that in a multi-vendor environment without writing tons of Ansible playbooks or Python code.

Interesting: Hugo with Docsy and AWS Amplify

Mat Jovanovic decided to follow my lead and migrate his blog from Blogger to Hugo, using Docsy theme, AWS Amplify as the CI/CD pipeline, and AWS S3 as the hosting platform.

Nice job… but he did way more than that - he documented the whole process, including tool selection, setup, and Blogger migration.

Thank you Mat! Every time I see someone publishing blog posts about open-source tools on Medium I’ll send them a link to your blog (with a comment “this is how you should blog about open-source solutions").

Video: Internet Has More than One Administrator

It’s amazing how many people assume that The Internet is a thing, whereas in reality it’s a mishmash of interconnected independent operators running mostly on goodwill, misplaced trust in other people’s competence, and (sometimes) pure dumb luck.

I described a few consequences of this sad reality in the Internet Has More than One Administrator video (part of How Networks Really Work webinar), and Nick Buraglio and Elisa Jasinska provided even more details in their Surviving the Internet Default-Free Zone webinar.

You need Free ipSpace.net Subscription to watch the video, and the Standard ipSpace.net Subscription to watch the Surviving in the Internet Default-Free Zone webinar.

Example: Deploy a Web Server in AWS

The third hands-on exercise in our Networking in Public Cloud Deployments online course asks the students to deploy a web server in a public cloud of their choice using infrastructure-as-code principles.

Not surprisingly, Erik Auerswald created another fantastic writeup when solving that exercise, including exploring the problem space, detailed description of his Terraform-based solution, and testing procedures. Enjoy!

AWS Networking 101

There was an obvious invisible elephant in the virtual Cloud Field Day 7 (CFD7v) event I attended in late April 2020. Most everyone was talking about AWS, how their stuff runs on AWS, how it integrates with AWS, or how it will help others leapfrog AWS (yeah, sure…).

Although you REALLY SHOULD watch my AWS Networking webinar (or something equivalent) to understand what problems vendors like VMWare or Pensando are facing or solving, I’m pretty sure a lot of people think they can get away with CliffsNotes version of it, so here they are ;)

Explore: BGP in Data Center Fabrics

Got mentioned in this tweet a while ago:

Watching @ApstraInc youtube stream regarding BGP in the DC with @doyleassoc and @jtantsura.Maybe BGP is getting bigger and bigger traction from big enterprise data centers but I still see an IGP being used frequently. I am eager to have @ioshints opinion on that hot subject.

Maybe I’ve missed some breaking news, but assuming I haven’t my opinion on that subject hasn’t changed.

When EVPN EBGP Session between Loopbacks Makes Sense

One of the attendees of our Building Next-Generation Data Center online course submitted a picture-perfect solution to scalable layer-2 fabric design challenge:

  • VXLAN/EVPN based data center fabric;
  • IGP within the fabric;
  • EBGP with the WAN edge routers because they’re run by a totally different team and they want to have a policy enforcement point between the two;
  • EVPN over IBGP within the fabric;
  • EVPN over EBGP between the fabric and WAN edge routers.

The only seemingly weird decision he made: he decided to run the EVPN EBGP session between loopback interfaces of core switches (used as BGP route reflectors) and WAN edge routers.

Webinars in May 2020

Being stuck at home like most everyone else we’re continuing the increased pace of content production in May 2020:

  • I’ll continue the Introduction to Containers and Docker update. We got through the basics the last time and will cover Linux namespaces and how Docker uses them on May 5th.
  • We finally found an independent guest speaker familiar with Cisco ACI. Mario Rosi will start the Cisco ACI series with an introductory webinar on May 12th.
  • Dinesh Dutt will continue his Network Automation Tools update on May 19th.
  • Hoping to get through Introduction to Docker on May 5th, I plan to do a deep dive into Docker Networking on May 26.
  • Finally, I’m positive I won’t cover all the bridging and routing material I created in today’s webinar, so we’ll continue with routing protocol basics on May 28th.

Network Automation and Hammer of Thor

Imagine that you just stumbled upon the hammer Thor carelessly dropped, and you’re so proud of your new tool that everything looks like a nail even though it might be a lightbulb or an orange.

That happens to some people when they get the network automation epiphany: all of a sudden CLI and manual configuration should be banned, and everything can be solved by proper incantation of Git and Ansible commands or whatever other workflow you might have set up… even though the particular problem might have nothing to do with what you have just automated.

I’m not saying we should keep using box-by-box CLI for daily operations or mundane configuration tasks. I’m just saying that the world is not as binary as some people want it to be.

MUST READ: When Programming a System with High Kinetic Energy

Kode Vicious (aka George V. Neville-Neil ) wrote another brilliant article on reducing risk in systems that can do serious harm. Here are just two of the gems:

The risks involved in these systems come from three major areas: marketing, accounting, and management.

There is a wealth of literature on safety-critical systems, much of which points in the same direction: toward simplicity. With increasing complexity comes increasing risk …

For whatever reason most networking- and virtualization vendors joined a lemming-like run in the opposite direction years ago.

Overlay Networking with Ouroboros on Software Gone Wild

This podcast introduction was written by Nick Buraglio, the host of today’s podcast.


As private overlays are becoming more and more prevalent and as SD-WAN systems and technologies advance, it remains critical that we continue to investigate how we think about internetworking. Even with platforms such as Slack Nebula, Zerotier, or the wireguard based TailScale becoming a mainstream staple of many businesses, the question of “what is next” is being asked by an ambitious group of researchers.

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