Author Archives: Ivan Pepelnjak
Author Archives: Ivan Pepelnjak
When people started talking about OpenConfig YANG data models, my first thought (being a grumpy old XML/XSLT developer) was “that should be really easy to implement for someone with XML-based software and built-in XSLT support” (read: Junos with SLAX).
Here’s how my simplistic implementation would look like:
Read more ...One of the common taglines parroted by SDN aficionados goes along the lines of “The cost to acquire and manage server and storage architectures has declined over time while networking stays stubbornly expensive.” (I took it straight from an anonymous blog comment).
Let’s see how well it matches reality.
Read more ...Got this challenge from one of my readers:
I've recently changed jobs and I am currently working for a telco. The problem is that I have no idea of what they are talking about when they mention SGSN, GGSN, Gi, Gn, etc... I only know routing and switching stuff :(.
Obviously he tried to search for information and failed.
Read more ...When LinkedIn announced their Project Falco I knew exactly what one of my future Software Gone Wild podcasts would be: a chat with Russ White (Mr. CCDE, now network architect @ LinkedIn).
It took us a long while (and then the summer break intervened) but I finally got it published: Episode 62 is waiting for you.
Here are the outlines of an interesting ExpertExpress discussion:
Should they buy L2VPN and use MACsec on it or L3VPN and use GETVPN on it (considering they already have large DMVPN deployments in each region)?
Read more ...One of the oft-repeated messages of the Software-Defined Pundits is “Standard bodies are broken, (open) source code is king”… and I’d guess that anyone who was too idealistic before being exposed to how the sausage is being made within IETF has no problems agreeing with them. However…
Read more ...Matt Oswalt made two great points while tweeting about my Automation Gone Wild blog post:
However, life is not always rosy, so @stupidengineer asked:
Read more ...I love listening to Scott Lowe’s Full Stack Journey podcast, so I was totally delighted when he asked me to participate. The results: FSJ Episode#8. Enjoy!
While most readers, commenters, and Twitterati agreed with my take on the uselessness of OSPF areas and inter-area summarization in 21st century, a few of them pointed out that in practice, the theory and practice are not the same. Unfortunately, most of those counterexamples failed due to broken implementations or vendor “optimizations”.
Read more ...Does it make sense to run OpenStack on top of VMware infrastructure? How well does NSX work as a Neutron plug-in? Marcos Hernandez answered these questions (and a lot of others) in the Episode 61 of Software Gone Wild (admittedly after a short marketing pitch in the first 10 minutes).
One of my readers left this question on the blog post resurfacing the idea of running BGP between servers and ToR switches:
When using BGP on a VM for mobility, what is the best way to establish a peer relationship with a new TOR switch after a live migration? The VM won't inherently know the peer address or the ASN.
As always, the correct answer is it depends.
Read more ...Marcel Reuter sent me a few questions about my upcoming Network Automation workshop. You might find them interesting, so here they are:
We have a lab with virtual IOS-XE, IOS-XR and Junos (vMX) router. I would like to learn how to provisioning the Lab router.
Covered in the workshop. I’m focusing on vIOS (which is pretty close to IOS Classic and IOS-XE) and Nexus OS because that’s what I can get up and running quickly in VIRL.
Read more ...One of my ExpertExpress design discussions focused on WAN network design and the need for OSPF areas and summarization (the customer had random addressing and the engineers wondered whether it makes sense to renumber the network to get better summarization).
I was struggling with the question of whether we still need OSPF areas and summarization in 2016 for a long time. Here are my thoughts on the topic; please share yours in the comments.
Read more ...In the Leaf-and-Spine Fabric Designs webinar series we started with the simplest possible design: non-redundant server connectivity with bridging within a ToR switch and routing across the fabric.
After I explained the basics (including routing protocol selection, route summarization, link aggregation and addressing guidelines), Dinesh Dutt described how network architects use BGP when building leaf-and-spine fabrics.
Eluehike Chedu asked an interesting question after my explanation of why stretched ACI fabric (or alternatives, see below) is the least horrible way of stretching a subnet: What about OTV?
Time to go back to the basics. As Dinesh Dutt explained in our Routing on Hosts webinar, there are (at least) three reasons why people want to see stretched subnets:
Read more ...One of my readers sent me this question:
Have you written something about assessment and planning for migration of traditional in-premise data center network to private or public cloud? There would be hundreds of things to check during assessment and then plan accordingly.
Academically, that’s a wrong way of approaching the problem.
Read more ...When I talk about network automation with enterprise engineers I usually get responses along the lines of “That’s interesting, but it will never happen in my organization. That’s what startups or cloud providers do.”
They couldn’t be more wrong: Thomas Wacker from UBS (one of the top 20 global financial services companies in case you don’t recognize the name) will describe how UBS uses network automation in new data center deployments during our Network Automation DIGS SDN event on September 1st, and we’ll spend the rest of the afternoon focusing on how you could get started and what your first network automation project should be.
Read more ...Andrew wondered how one could scale the L3-only data center networking approach I outlined in this blog post and asked:
When dealing with guests on each host, if each host injects a /32 for each guest, by the time the routes are on the spine, you're potentially well past the 128k route limit. Can you elaborate on how this can scale beyond 128k routes?
Short answer: it won’t.
Read more ...Software Gone Wild podcast is well into its toddler years and it was time for a teambuilding exercise. Just kidding – we wanted to test new tools and decided to discuss the vacation experiences and podcast ideas while doing that.
On a more serious note: we’re always looking for cool projects, implementations and ideas. Contact us at podcast (-the weird sign-) ipspace.net.
My “this is why you need automation” blog post triggered numerous comments and tweets. I loved this one:
What if the mistake was embedded into the automation process/tool (designed by humans) in the first place? Now you have a video series titled "Automation Gone Wild".
I guess this tweet is a priceless answer to that question:
Read more ...