Building network automation solutions

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Category: SDN

Can We Make REST API Transactional Across Multiple Calls?

I got interesting feedback from one of my readers after publishing my REST API Is Not Transactional blog post:

One would think a transactional REST interface wouldn’t be too difficult to implement. Using HTTP1/1, it is possible to multiplex several REST calls into one connection to a specific server. The first call then is a request for start a transaction, returning a transaction ID, to be used in subsequent calls. Since we’re not primarily interested in the massive scalability of stateless REST calls, all the REST calls will be handled by the same frontend. Obviously the last call would be a commit.

I wouldn’t count on HTTP pipelining to keep all requests in one HTTP session (mixing too many layers in a stack never ends well) but we wouldn’t need it anyway the moment we’d have a transaction ID which would be identical to session ID (or session cookie) traditional web apps use.

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Net2Text: Natural-Language Interface to Network Operations

Sick-and-tired of intent-based GUIs that are barely better than CiscoWorks on steroids? How about asking Siri-like assistant queries about network state in somewhat-limited English and getting replies back in full-blown sentences?

Warning: you might be reentering the land of unicorns driving flying DeLoreans... but then keep in mind what Arthur Clarke had to say on this topic ;).

Welcome to Net2Text, another proof-of-concept tool created by the group led by Laurent Vanbever… who joined us for a short chat to discuss it, resulting in Episode 105 of Software Gone Wild.

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Beware the Marketing Magic of GUI-Based Programming

Someone working for a network automation startup desperately tried to persuade me how cool their product is. Here’s what he sent me:

We let network engineers build their own network automation solutions in no time without requiring coding or scripting knowledge. It’s all GUI based, specifically geared towards network engineers - they can simply model services or roll-out networks “as-designed”.

The only problem: I’ve seen that same argument numerous times…

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If You Have to Simulate Your Whole Network, You're Doing It Wrong

This blog post was initially sent to subscribers of my SDN and Network Automation mailing list. Subscribe here.

Have you ever seen a presentation in which a startup is telling you how awesome their product is because it allows you to simulate your whole network in a virtual environment? Not only that, you can use that capability to build a test suite and a full-blown CI/CD pipeline and test whether your network works every time you make a change to any one box in the network.

Sounds awesome, right? It’s also dead wrong. Let me explain why that’s the case.

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Device Configuration Synthesis with NetComplete on Software Gone Wild

When I was still at university the fourth-generation programming languages were all the hype, prompting us to make jokes along the lines “fifth generation will implement do what I don’t know how

The research team working in Networked Systems Group at ETH Zurich headed by prof. Laurent Vanbever got pretty close. The description of their tool says:

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Impact of Controller Failures in Software-Defined Networks

Christoph Jaggi sent me this observation during one of our SD-WAN discussions:

The centralized controller is another shortcoming of SD-WAN that hasn’t been really addressed yet. In a global WAN it can and does happen that a region might be cut off due to a cut cable or an attack. Without connection to the central SD-WAN controller the part that is cut off cannot even communicate within itself as there is no control plane…

A controller (or management/provisioning) system is obviously the central point of failure in any network, but we have to go beyond that and ask a simple question: “What happens when the controller cluster fails and/or when nodes lose connectivity to the controller?”

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As Expected: Where Have All the SDN Controllers Gone?

Roy Chua (SDx Central) published a blog post titled “Where Have All the SDN Controllers Gone” a while ago describing the gradual disappearance of SDN controller hype.

No surprise there - some of us were pointing out the gap between marketing and reality years ago.

It was evident to anyone familiar with how networking actually works that in a generic environment the drawbacks of orthodox centralized control plane SDN approach far outweigh its benefits. There are special use cases like intelligent patch panels where a centralized control plane makes sense.

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Programmable Packet Forwarding Pipelines Using P4 on Software Gone Wild

Every time a new simple programming language is invented, we go through the same predictable cycle:

  • Tons of hype;
  • Unbounded enthusiasm when people who never worked in target environment realize they could get something simple done in a short time;
  • Ever-worsening headaches as the enthusiasts try to get a real job done with the shiny new tool;
  • Disappointment;
  • A more powerful language is invented to replace the old one.

A few years ago we experienced the same cycle when OpenFlow was the-one-tool-to-bind-them all.

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Using Faucet to Build SC18 Network with OpenFlow

Remember how Nick Buraglio tried to use OpenDaylight to build a small part of SuperComputing conference network… and ended up with a programmable patch panel?

This time he repeated the experiment using Faucet SDN Controller – an OpenFlow controller focused on getting the job done – and described his experience in Episode 101 of Software Gone Wild.

We started with the usual “what problem were you trying to solve” and quickly started teasing apart the architecture and got geekily focused on interesting things like:

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From CCNA to SDN: Interview with David Bombal

A few weeks ago, I had an interesting video chat with David Bombal in which we covered a wide variety of topics including

  • What would you do if you started networking today?
  • How do you increase the value of your knowledge?
  • Networking hasn’t changed in the last 40 years and whatever you learn about networking will still be valid 20 years from now;
  • Why should I learn and implement network automation?
  • When should I start learning about network automation?

Note: David posted the whole list of topics with timestamps in the pinned comment under the video.

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Lock-In and SD-WAN: a Match Made in Heaven

This blog post was initially sent to subscribers of my SDN and Network Automation mailing list. Subscribe here.

I made a statement along these lines in an SD-WAN blog post and related email sent to our SDN and Network Automation mailing list:

The architecture of most SD-WAN products is thus much cleaner and easier to configure than traditional hybrid networks. However, do keep in mind that most of them use proprietary protocols, resulting in a perfect lock-in.

While reading that one of my readers sent me a nice email with an interesting question:

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Smart NICs and Related Linux Kernel Infrastructure

A while ago we did a podcast with Luke Gorrie in which he explained why he’d love to have simple, dumb, and easy-to-work-with Ethernet NICs. What about the other side of the coin – smart NICs with their own CPU, RAM and operating system? Do they make sense, when and why would you use them, and how would you integrate them with Linux kernel?

We discussed these challenges with Or Gerlitz (Mellanox), Andy Gospodarek (Broadcom) and Jiri Pirko (Mellanox) in Episode 99 of Software Gone Wild.

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