Q&A: Big Switch SDN

Got this set of questions from one of my readers:

I just met up with DELL guys for Big Switch SDN. They claim there is no routing running on leaf switches, the BCF is purely OpenFlow.

Almost true. It is based on OpenFlow, but they use tons of their own OpenFlow extensions to get stuff to work. That’s also why you have to install their agent on the switches.

First Speakers in Building Network Automation Solutions Online Course

Like with the Next-Generation Data Center course, the live sessions in the Building Network Automation Solutions course include guest speakers, Q&A discussions, and solutions to sample challenges that you’ll be able to use to complete your homework assignments.

The guest speakers for the January 2016 course include:

Video: Docker Networking Options

After introducing the fundamentals of Docker networking, Dinesh Dutt focused on various Docker networking options, including multi-host networking with overlays.

After watching the video, you might also want to listen to Episode 49 of Software Gone Wild with Brent Salisbury, Dave Tucker and Madhu Venugopal.

Can VMware NSX and Cisco ACI Interoperate over VXLAN?

I got a long list of VXLAN-related questions from one of my subscribers. It started with an easy one:

Does Cisco ACI use VXLAN inside the fabric or is something else used instead of VXLAN?

ACI uses VXLAN but not in a way that would be (AFAIK) interoperable with any non-Cisco product. While they do use some proprietary tagging bits, the real challenge is the control plane.

Network Automation Course for Environments Using $Vendor Platform

One of my readers wondered whether it makes sense to attend my Building Network Automation Solution course even if they plan to deploy a $Vendor platform.

It depends, this time on how fast and how far you want to proceed with network automation.

Worth Reading: DNS Is Part of the TCP/IP Stack

Another great blog post by Russ White: DNS is part of the TCP/IP stack, get used to it.

You might also want to tell application developers hard-coding IP addresses or anyone else believing in using /etc/hosts files instead of DNS that those things stopped being sexy around 1980.

Reliability of Clustered Solutions: Another Data Point

A while ago I wrote:

I haven’t seen any hard data, but intuition suggests that apart from hardware failures a standalone firewall might be more stable than a state-sharing firewall cluster.

Guillaume Sachot (working for a web hosting company) sent me his first-hand experience on this topic:

Becoming a Programmer on Software Gone Wild

During our summer team-building podcast we agreed it would be fun to record a few episodes along the “how do I become a programmer” theme and figured out that Elisa Jasinska would be a perfect first candidate.

A few weeks ago we finally got together and started our chat with campfire stories remembering how we got started with networking and programming.

L3 Virtualization and VRFs

I got into an interesting discussion with Johannes Luther on the need for VRFs and he wrote:

If VRF = L3 virtualization technologies, then I saw that link. However, VRFs are again just a tiny piece of the whole story.

Of course he’s right, but it turns out that VRFs are the fundamental building block of most L3 virtualization technologies using a shared infrastructure.

Network Automation: Lego Bricks and Death Stars

One of the challenges traditional networking engineers face when starting their network automation journey is the “build or buy” decision: should I use a plethora of small open-source or commercial tools and components and build my own solution, or should I buy a humongous platform from a reassuringly-expensive $vendor.

Most of us were used to buying platforms ranging from CiscoWorks to HP OpenView (oops, Business Technology Optimization Software) or now Cisco’s NSO, so it’s natural that we’re trying to map this confusing new world into old patterns, leading to interesting discussions like the one I had during one of my workshops:

New Webinar Series: Network Automation Use Cases

In June 2016 I got an interesting idea: let’s create a webinar series with numerous guest speakers that would describe several widely-used network automation use cases.

It took me almost half a year to get there, but finally the first session is scheduled for November 22nd.

Could You Use IS-IS Instead of BGP for Routing on Hosts?

One of my readers sent me an interesting question a while ago:

Isn’t IS-IS a better fit for building L3-only networks than BGP, particularly considering that IS-IS already has a protocol to communicate with the end systems (ES-IS)?

In theory, he’s correct (see also this blog post).

Optimize Your Data Center: How Far Did We Get?

Our Data Center optimization journey has finished. We virtualized the workload, got rid of legacy technologies, reduced the number of server uplinks, replaced storage arrays with distributed file system and replaced physical firewalls and load balancers with virtual appliances.

Let’s see what’s left: it turns out you really don’t need more than two switches in most data centers.

Optimal Inter-AS Routing Challenge

I encountered an ancient problem during one of my ExpertExpress engagements:

• Customer network is split into two autonomous systems (core and access);
• Links within access network are way slower than links within core network;
• Customer would like to have optimal core-to-access traffic flow.

Challenge: what’s the simplest possible configuration to get it done?

Breaking News: I’m a Vendor Shill

Got this comment on my Network Automation RFP Requirements blog post:

Looks like you are paid shill for Brocade based on the quote earlier in your blog "The Pass/Fail information included below was collected to the best of my knowledge with extensive help from Jason Edelman, Nick Buraglio, David Barroso and several Brocade engineers (THANK YOU!)."

Hooray, one more accolade to add to my list of accomplishments. And now for a few more details:

First Speakers in the Spring 2017 Data Center Course

It’s only two weeks since the last live session of the Autumn 2016 Data Center course in which Mitja Robas did a fantastic job describing a production deployment of VMware NSX on top of Cisco Nexus 9000 network, and we already have the first speakers for the Spring 2017 event:

• Scott Lowe (now at VMware) will talk about the role of open source in data center infrastructure;
• Thomas Wacker (UBS AG) will talk about their fully automated data center deployments;
• Andrew Lerner and Simon Richard (Gartner) will participate in a panel discussion on data center and networking trends.

NAPALM Update on Software Gone Wild

We did a podcast describing NAPALM, an open-source multi-vendor abstraction library, a while ago, and as the project made significant progress in the meantime, it was time for a short update.

NAPALM started as a library that abstracted the intricacies of network device configuration management. Initially it supported configuration replace and merge; in the meantime, they added support for diffs and rollbacks

To API or Not To API

One of my readers left this comment (slightly rephrased) on my Network Automation RFP Requirements blog post:

Given that we look up to our *nix pioneers as standard bearers for system automation, why do we demand an API from network devices? The API requirement would make sense if the vendor OS is a closed system. If an open system vendor creates APIs for applications running on their system (say for BGP configs) - kudos to them, but I no longer think that should be mandated.

He’s right - API is not a mandatory prerequisite for reliable network automation.

Do Enterprises Need MPLS?

Continuing the Do Enterprises Need VRFs discussion, let’s see which enterprise networks might need MPLS.

Do you need VRFs?

Read the previous blog post. If the answer is NO, you can stop reading. Otherwise, carry on.

New Webinar: Networks, Buffers and Drops

Do you need large buffers in data center switches or not? If you’re a vendor your take obviously depends on whether you have them or not, and then there are people saying “it’s bullshit” (mostly agree) and “look, I have a shinier toy” (get lost).

Unfortunately, it’s really hard to get someone who would know what he’s talking about, and be relatively unbiased.