Category: SDN

An anonymous commenter wrote this comment to my initial SD-WAN post:

I can still hardly imagine the business case behind SD-WAN. Any thoughts?

This question is really easy to answer. There’s a huge business case that SD-WAN products are aiming to solve: replacing traditional MPLS/VPN networks with encrypted transport over public Internet. However…

After I wrote a comment on a LinkedIn discussion in the Carrier Ethernet group (more details here), Vishal Sharma wrote an interesting response, going into more details of distinction between centralized control and centralized control plane.

One of the Software Defined Evangelists has declared 2015 as the Year of SD-WAN, and my podcast feeds are full of startups explaining how wonderful their product is compared to the mess made by legacy routers, so one has to wonder: is SD-WAN really something fundamentally new, or is it just another old idea in new clothes?

Elisa Jasinska, Bob McCouch and I were scheduled to record a NetOps podcast with a major vendor, but unfortunately their technical director cancelled at the last minute. Like good network engineers, we immediately found plan B and focused on Elisa’s specialty: open-source tools.

One of the potential attendees of my SDN workshop sent me a long list of questions. Almost every networking engineer, team leader or CIO asks the first one:

What will happen, if we don´t follow the SDN hype (in the short term, in the medium term and in the long term)?

Answering this question is the whole idea of the workshop.

The up-to-date list of scheduled SDN workshops is available on my web site.

Every other week I stumble upon a high-level SDN article that repeats the misleading SDN is centralized control plane mantra (often copied verbatim from the Wikipedia article on SDN, sometimes forgetting to quote the source).

Yesterday, I had enough and decided to respond.

A while ago someone working for an IT-focused media site approached me with a short list of high-level questions. Not sure when they’ll publish the answers, so here they are in case you might find them interesting:

What can enterprises do to ensure that their infrastructure is ready for next-gen networking technology implementations emerging in the next decade?

Next-generation networks will probably rely on existing architectures and forwarding mechanisms, while being significantly more uniform and heavily automated.

What happens when network engineers with strong programming background and focus on open source tools have to implement network automation in a multi-vendor network? Instead of complaining or ranting about the stupidities of traditional networking vendors and CLI they write an abstraction layer that allows them to treat all their devices in the same way and immediately open-source it.

Packet Pushers podcast is a constant source of inspiration for my blog posts. Recently I stumbled upon Rob Sherwood’s explanation of how they package Big Cloud Fabric:

It’s a vertically integrated solution, from Switch Light OS to our SDN controller and Big Cloud Fabric application.

Really? What happened to openness and disaggregation?

A while ago Chris Young sent me a few questions about network management in the brave new SDN world. I never focused on network management, but I know a few people who do, including Terry Slattery and Matt Oswalt. Interop brought us all together, and we sat down one evening after the presentations to chat about the challenges of monitoring and managing SDN networks.

We started with easy things like comparing monitoring results from virtual and physical switches (and why they’ll never match and do we even care), and quickly diverted into all sorts of potential oscillations caused by overly-dynamic load balancing caused by flow label-based ECMP and flowlets.

With all the hype around Segment Routing we said: “let’s chat about it, what could possibly go wrong”. The result: Episode 33 of Software Gone Wild. We didn’t get very far into the technical details, but you might still find the overview useful (or not – do tell me how good or useless it is).

In June 2013 I wrote a rant that got stuck in my Evernote Blog Posts notebook for almost two years. Sadly, not much has changed since I wrote it, so I decided to publish it as-is.

In the meantime, the only vendor that’s working on making generic network deployments simpler seems to be Cumulus Networks (most other vendors went down the path of building proprietary fabrics, be it ACI, DFA, IRF, QFabric, Virtual Chassis or proprietary OpenFlow extensions).

Arista used to be in the same camp (I loved all the nifty little features they were rolling out to make ops simpler), but it seems they lost their mojo after the IPO.

Security groups (or Endpoint Groups if you’re a Cisco ACI fan) are a nice traffic policy abstraction: instead of dealing with subnets and ACLs, define groups of hosts and the rules of traffic control between them… and let the orchestration system deal with IP addresses and TCP/UDP port numbers.

When preparing for my Simplifying Application Workload Migration workshop (coming in webinar format in autumn) I tried to find a solution that would allow me to recreate existing enterprise virtual network infrastructure in a cloud environment. Soon I stumbled upon Ravello Systems, remembered hearing about them on a CloudCast.net podcast, and got in touch with them to figure out whether they could help me solve that challenge.

It turned you might use Ravello Systems’ solution to implement disaster recovery, but I got way more excited about the possibility to use their solution for labs or testing. To learn more about that, listen to Episode 32 of Software Gone Wild.

From the automation perspective, the RIPE conference is a dream come true – 30 seconds after you upload your presentation, it appears on the RIPE web site, it’s automatically updated on the podium computer, and the video recording of your talk is published before you even manage to get off the podium – so you can already watch my “SDN - 4 years later (aka Quo Vadis, SDN?)” presentation if you missed it yesterday.