Author Archives: Ivan Pepelnjak
Author Archives: Ivan Pepelnjak
Here’s another interesting talk from RIPE77: Routing Attacks in Cryptocurrencies explaining how BGP hijacks can impact cryptocurrencies.
TL&DR: Bitcoin is not nearly decentralized enough to be resistant to simple and relatively easy BGP manipulations.
Read more ...You know that time of year when snowflakes mean more than description of uniqueness of your networking infrastructure? Some people love to complain about that season and how the weather hinders them, others put on sturdy winter boots and down jackets, change tires on their car, and have tons of fun.
Network automation is no different. Sometimes you can persuade your peers that it makes sense to simplify and standardize the infrastructure to make it easier to abstract and automate (consider that an equivalent of going to a tropic island with shiny beaches and everlasting summer), other times you have to take out your winter boots and make the best out of what you got.
Read more ...In spring 2018 I started collecting real-life automation wins reported by the attendees of my Building Network Automation Solutions online course. I presented them at Troopers, and as a set of network automation use cases that are available to all ipSpace.net subscribers, some of them even with free subscription.
Today let’s start with how did it start story.
One of my readers sent me this question:
It would be nice to have a blog post or a webinar describing how to implement container networking in case when: (A) application does not tolerate NAT (telco, e.g. due to SCTP), (B) no DNS / FQDN, is used to find the peer element and (C) bandwidth requirements may be tough.
The only thing I could point him to is the Advanced Docker Networking part of Docker Networking Fundamentals webinar (available with free subscription) where macvlan and ipvlan are described.
Read more ...A lightning talk at the recent RIPE77 conference focused on shortcomings of VXLAN and rise of Geneve.
So what are those perceived shortcomings?
No protocol identifier – a single VXLAN VNI cannot carry more than one payload type. Let me point out that MPLS has the same shortcoming, as does IPsec.
Read more ...This blog post was initially sent to subscribers of my SDN and Network Automation mailing list. Subscribe here.
After publishing the Manual Work Is a Bug blog post, I got this feedback from Michele Chubirka explaining why automating changes in your network also increases network security:
Read more ...After explaining the basics of SD-WAN, Pradosh Mohapatra, the author of SD-WAN Overview webinar focused on SDWAN reference network design.
You need at least free ipSpace.net subscription to watch the video.
The “everyone should be a programmer” crowd did a really good job of scaring network engineers (congratulations, just what we need!). Here’s a typical question I’m getting:
Do I need to be good in scripting to attend your automation course.
TL&DR: Absolutely not.
Read more ...Here’s a question I got from someone attending the Building Next-Generation Data Center online course:
Cisco NCS5000 is positioned as a building block for a data center MPLS fabric – a leaf-and-spine fabric with MPLS and EVPN control plane. This raised a question regarding MPLS vs VXLAN: why would one choose to build an MPLS-based fabric instead of a VXLAN-based one assuming hardware costs are similar?
There’s a fundamental difference between MPLS- and VXLAN-based transport: the amount of coupling between edge and core devices.
Read more ...The last two months of 2018 will be jam-packed with webinars and on-site events:
December will be a storage, EVPN and SDN month:
Read more ...Yves Haemmerli, Consulting IT Architect at IBM Switzerland, sent me a thoughtful response to my we need product documentation rant. Hope you’ll enjoy it as much as I did.
Yes, whatever the project is, the real added value of an IT/network architect consultant is definitely his/her ability to create models (sometimes meta-models) of what exists, and what the customer is really looking for.
Read more ...I long while ago I stumbled upon an excellent resource describing why distributed systems are hard (what I happened to be claiming years ago when OpenFlow was at the peak of the hype cycle ;)… lost it and found it again a few weeks ago.
If you want to understand why networking is hard (apart from the obvious MacGyver reasons) read it several times; here are just a few points:
Read more ...A few years ago I got cornered by an enthusiastic academic praising the beauties of his cryptography-based system that would (after replacing the whole Internet) solve all the supposed woes we’re facing with BGP today.
His ideas were technically sound, but probably won’t ever see widespread adoption – it doesn’t matter if you have great ideas if there’s not enough motivation to implementing them (The Myths of Innovation is a mandatory reading if you’re interested in these topics).
Read more ...In early October I had a chat with Dinesh Dutt discussing the outline of the webinar he’ll do in November. A few days later Fastly published a blog post on almost exactly the same topic. Coincidence? Probably… but it does seem like observability is the next emerging buzzword, and Dinesh will try to put it into perspective answering these questions:
Read more ...In recent years Linux networking started evolving at an amazing pace. You can hear about all the cool new stuff at netdev conference… or listen to Episode 94 of Software Gone Wild to get a CliffsNotes version.
Roopa Prabhu, Jamal Hadi Salim, and Tom Herbert joined Nick Buraglio and myself and we couldn’t help diverging into the beauties of tc, and the intricacies of low-latency forwarding before coming back on track and started discussing cool stuff like:
Read more ...This blog post was initially sent to subscribers of my mailing list. Subscribe here.
In his Intent-Based Networking Taxonomy blog post Saša Ratković mentioned real-time change validation as one of the requirements for a true intent-based networking product.
Old-time networkers would instinctively say “sure, we need that” while most everyone else might be totally flabbergasted. After all, when you create a VM, the VM is there (or you’d get an error message), and when you write to a file and sync the file system the data is stored, right?
As is often the case, networking is different.
Read more ...After four live sessions we finished the VMware NSX Technical Deep Dive webinar yesterday. Still have to edit the materials, but right now the whole thing is already over 6 hours long, and there are two more guest speaker sessions to come.
Anyways, in the previous sessions we covered all the good parts of NSX and a few of the bad ones. Everything that was left for yesterday were the ugly parts.
Read more ...One of my friends reviewing the material of my AWS Networking webinar sent me this remark:
I'm always interested in hearing more about how AWS network works under the hood – it’s difficult to gain that knowledge.
As always, it’s almost impossible to find out the behind-the-scenes details, and whatever Amazon is telling you at their re:Invent conference should be taken with a truckload of salt… but it’s relatively easy to figure out a lot of things just by observing them and performing controlled experiments.
Read more ...This blog post was initially sent to subscribers of my mailing list. Subscribe here.
Following on his previous work with Cisco ACI Dirk Feldhaus decided to create an Ansible playbook that would create and configure a new tenant and provision a vSRX firewall for the tenant when working on the Create Network Services hands-on exercise in the Building Network Automation Solutions online course.
Read more ...Earlier this month I got this email from someone who had attended one of my online courses before and wanted to watch another one of them:
Is it possible for you to bundle a 1 year subscription at no extra cost if I purchase the Building Next-Generation Data Center course?
We were planning to do something along these lines for a long time, and his email was just what I needed to start a weekend-long hackathon.
End result: Expert ipSpace.net Subscription. It includes:
Read more ...