Category: Tags

AI

Artificial Intelligence (AI) and Machine Learning (ML) are the next big hype in networking following Software-Defined Everything and Intent-Based Everything. Like with the previous hype bubbles it’s worth figuring out

  • How much of the hype is real (TL&DR: not much)?
  • Whether the technology is ready to be used in production networks (TL&DR: some of it)
  • How you could use the technology to make your life easier

How Real Is It?

Like with the previous hype tsunamis I’ll do my best to help you figure out the answers to the above questions with a hefty dose of skepticism and snark1, starting with:

I also decided to “kick the tires” and document my (often less-than-stellar) experience with the most-overhyped products:

AI/ML in Networking: The Good, the Bad and the Ugly

Javier Antich created a wonderful AI/ML in Networking in 2021. If you know nothing about AI/ML and wonder whether you should care about it, you MUST watch these videos from his webinar:

In 2023, Javier published a book covering the same set of topics in way more details. I would highly recommend you read it if you want to know more.

What Others Are Saying

I keep collecting interesting articles talking about AI in general and (lately) ChatGPT. I found these interesting enough to mention them in worth reading blog posts:

These are not bad either:

Finally, a few real-life uses of large language models:

Blog Posts I Forgot to Categorize

  1. Please don’t blame me for pointing out the ever-lasting validity of Sturgeon’s law. Contrary to what some people think, I’m not trying hard to pick up dismal examples of AI failures, I’m just good at looking in the wrong places. Also, I’m too old to be wearing rosy glasses and drinking Kool-Aid. ↩︎

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OSPF

OSPF is like a traffic director for the internet. Imagine a city with many roads - OSPF helps routers (the traffic directors) figure out the best paths for data to travel from one place to another. It’s like a smart GPS for computers, making sure information takes the shortest and fastest routes. OSPF routers talk to each other, share maps of the internet, and decide the best ways to send data. It’s a cool system that keeps the internet running smoothly!

ChatGPT explaining OSPF to a high-school kid

Configuration Tips

This blog started as a collection of (hopefully) helpful configuration tricks, and I documented numerous Cisco IOS configuration tips in the early 2000s.

Implementation Details

Let’s start with the elephant in the room: OSPF areas – a simple concept that got way too convoluted when OSPF started accreting nerd knobs like NSSA areas:

OSPF default routes are another confusing topic. You could have inter-area default routes (used in stub areas) or external default routes that could be conditional or unconditional.

OSPF adjacencies are another fun troubleshooting topic:

The inimitable forwarding address in type-5 LSA will make your head explode when combined with the NSSA areas.

Want even more OSPF details? I documented way too many of them since I started blogging, including:

Deploying OSPF

Creative networking engineers often forget an unpleasant truth: OSPF is a single security domain. You should never run it with less-trusted peers, be it your customers, data center servers, or virtual machines.

OSPF by itself is complex enough, but the real fun starts when you combine it with other protocols (for example, BGP and LDP):

Running OSPF in large hub-and-spoke networks (for example, large DMVPN networks) is another tough challenge:

While you could use OSPF to get unequal-cost multipathing, you might be tripped by numerous caveats; no wonder there are few implementations of this concept.

Finally, you can run OSPF over unnumbered interfaces, be it point-to-point serial links or Ethernet segments:

Rants

Now and then, I couldn’t resist writing an OSPF-related rant:

What Others Are Writing About OSPF

Other OSPF Blog Posts

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LISP

LISP is a networking technology that has been searching for a relevant problem for a decade and a half (the LISP IETF working group started in the spring of 2009). Initially, I was cautiously optimistic. However, as LISP pivoted from an IPv6-over-IPv4 solution to a multihoming solution, then VM mobility and IP endpoint mobility solution, until it finally landed in Cisco Campus BU as the foundational technology of Software-Defined Access, I lost all hope.

LISP started as a DNS-like cache-based packet forwarding technology. Eventually, reality intervened, and the LISP believers rediscovered the flaws of cache-based forwarding. It looks like LISP pivoted to become a topology-driven PUB-SUB protocol. Assuming that’s correct, there’s little conceptual difference between LISP and EVPN. It’s just a question of defining a suitable set of policy mechanisms and developing an optimal implementation.

Discussing the benefits and drawbacks of LISP or EVPN thus makes as much sense as debating the number of angels dancing on the head of a pin, but that has never stopped people from doing one or the other.

Just in case you want to know more, you will find some details in the LISP-related blog posts I wrote since 2010:

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