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.
A reader of my blog sent me this question:
Do you think we can trust DSCP marking on servers (whether on DC or elsewhere - Windows or Linux )?
As they say “not as far as you can throw them”.
Does that mean that the network should do application recognition and marking on the ingress network node? Absolutely not, although the switch- and router vendors adore the idea of solving all problems on their boxes.
One of the hands-on exercises in our Networking in Public Cloud Deployments online course asks the attendees to deploy a full-blown virtual networking solution with a front-end (web) server in a public subnet, and back-end (database) server in a private subnet.
The next (optional) exercise asks them to add IPv6 to the mix for a full-blown dual-stack deployment.
Two weeks ago I started with a seemingly simple question:
If a BGP speaker R is advertising a prefix A with next hop N, how does the network know that N is actually alive and can be used to reach A?
… and answered it for the case of directly-connected BGP neighbors (TL&DR: Hope for the best).
Jeff Tantsura provided an EVPN perspective, starting with “the common non-arguable logic is reachability != functionality".
Now let’s see what happens when we add route reflectors to the mix. Here’s a simple scenario:
We started March 2020 with the second part of Cisco SD-WAN webinar by David Peñaloza Seijas, continued with Upcoming Internet Challenges update, and concluded with 400 GE presentation by Lukas Krattiger and Mark Nowell.
You can access all these webinars with Standard or Expert ipSpace.net subscription. The Cisco SD-WAN presentation is already available with free ipSpace.net subscription, which will also include the edited 400 GE videos once we get them back from our video editor.
However, there’s a slight gotcha if you use Git with Markdown: whenever you change something, the whole line (and using tools like IA Writer a whole paragraph is a single line) is marked as changed, for example:
Maybe it’s time to build our own network monitoring systems from open-source components instead of paying vendors big bucks for slick PowerPoint slides.
David Penaloza decided to demystify Cisco’s SD-WAN, provide real world experience beyond marketing hype, and clear confusing and foggy messages around what can or cannot be done with Cisco SD-WAN.
One of the attendees of my Building Network Automation Solutions online course quickly realized a limitation of Ansible (by far the most popular network automation tool): it stores all the information in random text files. Here’s what he wrote:
I’ve been playing around with Ansible a lot, and I figure that keeping random YAML files lying around to store information about routers and switches is not very uh, scalable. What’s everyone’s favorite way to store all the things?
He’s definitely right (and we spent a whole session in the network automation course discussing that).
Let’s agree for a millisecond that you can’t find any other way to migrate your workload into a public cloud than to move the existing VMs one-by-one without renumbering them. Doing a clumsy cloud migration like this will get you the headaches and the cloud bill you deserve, but that’s a different story. Today we’ll talk about being clumsy the right and the wrong way.
There are two ways of solving today’s challenge:
I’d like to bring back EVPN context. The discussion is more nuanced, the common non-arguable logic here - reachability != functionality.
Numerous online companies are using the COVID-19 crisis to make their products better known (PacketPushers collected some of them). Nothing wrong with that - they’re investing into providing free- or at-cost resources, and hope to get increased traction in the market. Pretty fair and useful.
Then there are others… Here’s a recent email I got:
It’s amazing how many people still believe in Security Fairy (the mythical entity that makes your application magically secure), fueling the whole industry of security researchers who happily create excruciatingly detailed talks of how you can use whatever security oversight to wreak havoc (even when the limitations of a technology are clearly spelled out in an RFC).
In the Networks Are Not Secure (part of How Networks Really Work webinar) I described why we should never rely on network infrastructure to provide security, but have to implement it higher up in the application stack.
Andrea Dainese added REST (Web) API to his Automation for Cisco NetDevOps article. You might love his explanation of the screen scraping methods used by legacy implementations. He was too polite to throw around any names, but I could immediately think of NETCONF or RESTCONF implementation on Cisco IOS.
One of our subscribers sent me this email when trying to use ideas from Ansible for Networking Engineers webinar to build BGP route reflector configuration:
I’m currently discovering Ansible/Jinja2 and trying to create BGP route reflector configuration from Jinja2 template using Ansible playbook. As part of group_vars YAML file, I wish to list all route reflector clients IP address. When I have 50+ neighbors, the YAML file gets quite unreadable and it’s hard to see data model anymore.
Whenever you hit a roadblock like this one, you should start with the bigger picture and maybe redefine the problem.