TCP in the Data Center and Beyond on Software Gone Wild

In autumn 2016 I embarked on a quest to figure out how TCP really works and whether big buffers in data center switches make sense. One of the obvious stops on this journey was a chat with Thomas Graf, Linux Core Team member and a founding member of the Cilium project.

Running vSphere on Cisco ACI? Think Twice…

When Cisco ACI was launched it promised to do everything you need (plus much more, and in multi-hypervisor environment). It was quickly obvious that you can’t do all that on ToR switches, and need control of the virtual switch (the real network edge) to get the job done.

To YANG or Not to YANG, That’s the Question

Yannis sent me an interesting challenge after reading my short “this is how I wasted my time” update:

We are very much committed in automation and use Ansible to create configuration and provision our SP and data center network. One of our principles is that we do rely solely on data available in external resources (databases and REST endpoints), and avoid fetching information/views from the network because that would create a loop.

You can almost feel a however coming in just a few seconds, right?

SDN Use Cases: Featured Webinar in March 2017

The featured webinar in March 2017 is the SDN Use Cases webinar describing over a dozen different real-life SDN use cases. The featured videos cover four of them: a data center fabric by Plexxi, microsegmentation (including VMware NSX), SDN-based Internet edge router built by David Barroso, and Fibbing - an OSPF-based traffic engineering developed at University of Louvain.

To view the videos, log into my.ipspace.net, select the webinar from the first page, and watch the videos marked with star.

Worth Reading: Building an OpenStack Private Cloud

It’s uncommon to find an organization that succeeds in building a private OpenStack-based cloud. It’s extremely rare to find one that documented and published the whole process like Paddy Power Betfair did with their OpenStack Reference Architecture whitepaper.

I was delighted to see they decided to do a lot of things I was preaching for ages in blog posts, webinars, and lately in my Next Generation Data Center online course.

Highlights include:

Video: Out-of-Band SDN Management Network

One of the challenges of designing a controller-based solution is the transport network used to exchange information between controller and controlled devices. Can you do that in-band or is it better to have an out-of-band network (built with traditional components)? Terry Slattery explained some of the pros and cons in the Monitoring SDN Networks webinar.

NETCONF Transactional Consistency on Cisco IOS XE

During the Tech Field Day Extra event at Cisco Live Europe 2017 Fabrizio Maccioni, Technical Marketing Engineer at Cisco, described enhanced programmability available in Cisco IOS XE release 16.x. What really got my attention was the claim that they made NETCONF on Cisco IOS transactional (and Fabrizio mentioned the candidate config and commit).

Here's my initial reaction:

Are You Ready for Building Next-Generation Data Center Course?

I often get questions from engineers wondering whether my webinars or courses would be too tough for them. Here’s a question I got from an engineer who wanted to attend my Building Next-Generation Data Center course: “What specific prior experience do you expect for this workshop?”

The Ever-Increasing Complexity

Eyvonne Sharp wrote a great blog post describing Cisco’s love of complexity and how SD-WAN vendors proved things don’t have to be that complex.

I know Cisco (and every other vendor) loves making ever-more-complex solutions that lock you into their morass for the rest of your life (long-distance vMotion anyone?).

Worth Reading: Agile Development and Security

Matthias Luft (a good friend of mine, and a guest speaker in the upcoming Building Next-Generation Data Center course) wrote a great post about the (lack of) security in software development.

The parts I like most (and they apply equally well to networking):

CloudScale ASICs on Software Gone Wild

Last year Cisco launched a new series of Nexus 9000 switches with table sizes that didn’t match any of the known merchant silicon ASICs. It was obvious they had to be using their own silicon – the CloudScale ASIC. Lukas Krattiger was kind enough to describe some of the details last November, resulting in Episode 73 of Software Gone Wild.

For even more details, watch the Cisco Nexus 9000 Architecture Cisco Live presentation.

Nerd Knobs Save the Day: NSSA Saga Continues

Remember the OSPF NSSA Forwarding Address kludge and its consequences? Let’s figure out whether the nerd knobs available in Cisco IOS can save the day.

TL&DR: Don’t use OSPF areas if you can avoid them. Don’t use NSSA areas.

Guest Speakers in the Building Next-Generation Data Center Course

I managed to get another awesome lineup of guest speakers for the Spring 2017 Building Next-Generation Data Center course (starting in less than a month):

Scott Lowe will open the course with a presentation on the impact of open source software in data center environments.

Navigating Complex Data Structures in Ansible Playbooks

Have you ever tried to navigate complex data structures within Ansible playbooks using awkward looping constructs and convoluted map filters?

It might be easier to munge the data structure into a more appropriate format first and then use the munged data in subsequent tasks. Wondering how to do it?

Leaf-and-Spine Fabrics versus Fabric Extenders

One of my readers wondered what the difference between fabric extenders and leaf-and-spine fabrics is:

We are building a new data center for DR and we management is wanting me to put in recommendations to either stick with our current Cisco 7k to 2k ToR FEX solution, or prepare for what seems to be the future of DC in that spine leaf architecture.

Let’s start with “what is leaf-and-spine architecture?”

Newer Docker Networking Options

In the last part of the free Docker Networking Fundamentals webinar Dinesh Dutt described the newer high-performance networking options (Macvlan and Ipvlan) introduced in Docker version 1.12.

Facebook Backpack Behind the Scenes

When Facebook announced 6-pack (their first chassis switch) my reaction was “meh” (as well as “I would love to hear what Brad Hedlund has to say about it”). When Facebook announced Backpack I mostly ignored the announcement. After all, when one of the cloud-scale unicorns starts talking about their infrastructure, what they tell you is usually low on detail and used primarily as talent attracting tool.

NextGenDC: Securing a Hybrid Cloud with Matthias Luft

Imagine you were asked to migrate some of the workloads running in your data center into a public (or managed) cloud. These workloads still have to access the data residing in your data center – a typical hybrid cloud deployment.

Next thing you know you have to deal with your (C)ISO and his/her usual concerns as well as the variety of articles on tech sites stating that "security is the biggest challenge of cloud adoption".

Network Automation and Undifferentiated Heavy Lifting

I got this tweet after publishing the “use Ansible to execute a single command on all routers” blog post (and a few similar comments on the blog post itself)

Or use Python, Netmiko and a simple For loop

I never cease to be amazed by the urge to do undifferentiated heavy lifting in the IT industry.

Q&A: Migrating to Modern Data Center Infrastructure

One of my readers sent me a list of questions after watching some of my videos, starting with a generic one:

While working self within large corporations for a long time, I am asking myself how it will be possible to move from messy infrastructure we grew over the years to a modern architecture.

Usually by building a parallel infrastructure and eventually retiring the old one, otherwise you’ll end up with layers of kludges. Obviously, the old infrastructure will lurk around for years (I know people who use this approach and currently run three generations of infrastructure).