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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At the end of my vNIC 2018 keynote speech I made a statement along these lines:
The moment you start using GUI with an SDN product you’re back to square one.
That claim confused a few people – Mark left this comment on my blog:
Read more ...Approximately two years ago I tried to figure out whether aggressive marketing of deep buffer data center switches makes sense, recorded a few podcasts on the topic and organized a webinar with JR Rivers.
Not surprisingly, the question keeps popping up, so it seems it’s time for another series of TL&DR articles. Let’s start with the basics:
Read more ...Remember the avoid duplicate data in network automation data models challenge and the restructuring we did to represent a network as a graph.
Well, I was not happy with the end result - I hated the complexity of supporting Jinja2 templates that had to check left- and right nodes of a link, so I generalized the data structure a bit, and all of a sudden I could model stub interfaces, P2P links and multi-access networks.
A while ago I had an interesting consulting engagement: a multinational organization wanted to migrate off global Carrier Ethernet VPN (with routers at the edges) to MPLS/VPN.
While that sounds like the right thing to do (after all, L3 must be better than L2, right?) in that particular case they wanted to combine the provider VPN with Internet-based IPsec VPN… and doing that in parallel with MPLS/VPN tends to become an interesting exercise in “how convoluted can I make my design before I give up and migrate to BGP”.
Read more ...Found a fantastic list of common logical fallacies. It's a must read for anyone having at least occasional interaction with non-Vulcans... and when you stop laughing (or screaming, or both) make sure you go through the companion web site to understand bugs in your wetware that sabotage your attempts at being perfectly logical.
I’m always amazed at how fast the time flies. I have no idea where May disappeared to, it seems like it was only yesterday when I was writing about webinar plans in 2019… and yet it’s only a month till ipSpace.net Summer Break™.
During June 2019 I’ll continue updating Designing the Private Cloud Infrastructure webinar, and start a new pet project: How Networks Really Work – I’m literally minutes away from traveling to a quiet spot in the middle of nowhere where I’ll work on the materials. In between these webinars you’ll find me in Zurich where I’ll run Microsoft Azure Networking workshop on June 12th in parallel with SIGS Technology Conference.
As you might expect we have plenty of things already lined up for autumn 2019… more about that in a week or two.
I hate listening to “this is what we were doing this year” podcasts as they usually turn into pointless blabbering, self-congratulations and meaningless plans (think New Year resolutions). The Full Stack Journey Episode 28 with Scott Lowe was an amazing deviation from this too-common template.
If you don’t have time to listen to the podcast (but you OUGHT TO do it) here’s what I loved most: “When faced with the onslaught of new technologies, don’t panic. Wait a few months to see which ones survive”.
Read more ...TL&DR: MIA
Six years ago, when I was talking about overlay virtual networks at Interop, I loved to joke that we must be living on a weird planet where Microsoft has the best overlay virtual networking implementation… at least as far as IPv6 goes.
Even then, their data plane implementation which was fully dual-stack-aware on both tenant- and underlay level was way ahead of what System Center could do.
Read more ...Last week I explained how you could take a typical first attempt at a network automation data model and reduce the amount of duplicate data… but the data model we used was still describing a set of seemingly disconnected boxes.
How about restructuring the whole thing and describing what networks really are - graphs made of nodes (network devices) and links?
More than a decade ago I decided to start a pet project: a blog describing interesting details of networking technologies. The idea quickly morphed into vendor-neutral webinars - the first one took place in February 2010. A year or two later I had my first guest speaker and as of today we had more than 50 industry experts participating in ipSpace.net webinars and online courses.
In the meantime the ipSpace.net team grew: I had video and audio editors for years, Irena Marčetič took over marketing, logistics, and production in 2018, and we got a team of webinar moderators that will help us with guest speaker webinars (last week we ran the first guest speaker webinar where I didn’t have to be involved - hooray ;)
Read more ...Kate Matsudaira wrote a nice article explaining how to deal with emotional attachment to a project you spent a lot of time working on. While she's focusing on software development, the same fallacies apply to networking - sometimes it's time to let the old pile of **** die and replace it with something created in this decade.
A few years ago we “celebrated” 512K day - the size of the full Internet routing table exceeded 512K (for whatever value of K ;) prefixes, overflowing TCAMs in some IP routers and resulting in interesting brownouts.
We’re close to exceeding 768K mark and the beware 768K day blog posts have already started appearing. While you (RFC 2119) SHOULD check the size of your forwarding table and the maximum capabilities of your hardware, the more important question should be “Why do I need 768K forwarding entries if I’m not a Tier-1 provider”
Read more ...This blog post was initially sent to subscribers of my SDN and Network Automation mailing list. Subscribe here.
Remember the “every device configuration is really an expression of our intent” discussion? Forgetting the wrong level of abstraction (we mostly don’t want to deal with all the idiosyncratic stuff network devices want to see in their configurations) and box-oriented thinking caused by device-level intent for the moment, let’s focus on another aspect: how hard is it to manage your intent?
Read more ...Remember how Arista promoted VXLAN coupled with deep buffer switches as the perfect DCI solution a few years ago? Someone took Arista’s marketing too literally, ran with the idea and combined VXLAN-based DCI with traditional MLAG+STP data center fabric.
While I love that they wrote a blog post documenting their experience (if only more people would do that), it doesn’t change the fact that the design contains the worst of both worlds.
Here are just a few things that went wrong:
Read more ...One of the toughest challenges in the hands-on part of Building Network Automation Solutions online course is the create a data model describing your service exercise.
Networking engineers never had to think about data models describing their networks or services, and the first attempt often results in something that looks like simplified device configuration in YAML or JSON format.
I wrote a long article describing how you can slowly redesign your box-focused data model into a network-focused one. The first parts describing the problem and initial deduplication are already online.
After a few weeks of venting my frustrations on Twitter I finally completed Microsoft Azure Networking slide deck last week and published the related demos on GitHub.
I will use the slide deck in a day-long workshop in Zurich (Switzerland) on June 12th and run a series of live webinar sessions in autumn. If you’re a (paid) subscriber you can already download the slides and it would be great if you’d have time to attend the Zurich workshop – it’s infinitely better to discuss interesting challenges face-to-face than to type questions in a virtual classroom.
Every time a new simple programming language is invented, we go through the same predictable cycle:
A few years ago we experienced the same cycle when OpenFlow was the-one-tool-to-bind-them all.
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Imagine a small bank deciding in their infinite wisdom (in reality: because their CIO attended a conference organized by a database vendor) to implement their banking software by teaching bank tellers how to type SQL transactions by hand.
For example, to transfer money from one account to another account, a bank teller could simply type:
Read more ...Russ White recently wrote an interesting blog post claiming how we should not ignore any particular technology just because it was invented by a hyperscaler illustrating his point with a half-dozen technologies that were first used by NASA.
However, there are “a few” details he glossed over:
Read more ...