Blog Posts in August 2015
My first ride with Uber was a love at first sight – the amount of friction they managed to remove from using-a-taxi process is unbelievable.
However, every love story eventually faces real-life issues, and what really matters is how you handle them at that point.
Robin Harris described an interesting problem in his latest blog post: while you can reduce the storage access time from milliseconds to microseconds, the whole software stack riding on top still takes over 100 milliseconds to respond. Sometimes we’re optimizing the wrong part of the stack.
A link on Bruce Schneier’s blog pointed me to the latest article by the truly awesome James Mickens, this time making great fun of security researchers. Exactly what you need with your coffee on a Saturday morning. Enjoy!
After introducing the concepts of Cumulus Linux in the Data Center Fabrics update session, Dinesh Dutt described the typical data center architectures implemented with Cumulus Linux and the lessons everyone should learn from large-scale web properties.
SDN will give more control and flexibility over the network to the customer/user/network-admin. They will be able to program their equipment themselves, they will be able to tweak routing algorithms in the central controller. They get APIs to hook into the heart of the intelligence. They get more config-knobs. It's gonna be awesome.
However, he thinks (and I agree) that this vision doesn’t make sense:
Open Networking Foundation has this nice and crisp definition of SDN:
[SDN is] The physical separation of the network control plane from the forwarding plane, and where a control plane controls several devices.
Using this definition it was easy to figure out whether certain architecture complies with ONF definition of SDN. It was also easy to point out why it was ridiculous.
In the Can Virtual Routers Compete with Physical Hardware blog post I mentioned that SSL termination remains one of the few bastions of hardware acceleration.
Based on the comment made by RPM, it looks like I was wrong.
Here’s his reasoning:
One of my readers wondered how long my NFV webinar is supposed to take (and I forgot to add that information to my web site), so he sent me this question: “How long is this webinar? An hour? Two hours? If it says "webinar" does that imply a 60 minute duration, so I shouldn't ask?”
Short answer: live webinar sessions usually take between 90 minutes and 2 hours depending on the breadth of the topic, however…
With the advent of layer-3 leaf-and-spine data center fabrics, it became (almost) possible to build pure layer-3-only data center networks… if only the networking vendors would do the very last step and make every server-to-ToR interface a layer-3 interface. Cumulus decided to do just that.
One of my readers sent me a heartfelt email that teleported me 35 years down the memory lane. He wrote:
I only recently stumbled upon your blog and, well, it hurt. It's incredible the amount of topics you are able to talk about extensively and how you can dissect and find interesting stuff in even the most basic concepts.
May I humble ask how on earth can you know all of the things you know, with such attention to detail? Have you been gifted with an excellent memory, magical diet, or is it just magic?
Short answer: hard work and compound interest.
A few weeks ago I decided to join the SDN group on LinkedIn and quickly discovered the biggest problem of SDN – many people, who try to authoritatively talk about it, have no idea what they’re talking about. Here’s a gem (coming from a “network architect”) I found in one of the discussions:
The SDN local controller can punt across to remote datacenters using not only IP, but even UDP over MPLS
Do I have to explain how misguided that statement is?
Whenever you talk to a new startup evaluating whether you’d consider including their products in your network, don’t forget to ask them a fundamental question: “does your product support IPv6?”
If they reply “Nobody has ever asked for it”, it’s time to turn around and run away.
As expected, he started with the big picture: what is Cumulus Networks and Cumulus Linux all about?
It’s hard to visit an IT journal web site without stumbling upon an SDN fairy tale. Here’s another one:
The idea is to cut away the manual process of setting up new firewalls, load balancers and other network appliances, and instead open the door to provisioning a new network infrastructure within a few minutes.
And why exactly is it that you can’t do that today?
35 years ago, mainframes, single-protocol networks (be it SNA or DECnet), and centralized architectures that would make hard-core SDN evangelists gloat with unbridled pride were all the rage. If you’re old enough to remember IBM SNA, you know what I’m talking about.
A few years later, everything changed.
These presentations focus more on the application-level technologies (client- and server side), but I’m positive you’ll find some useful content in the caching and scale-out applications with load balancing sections.
Gartner has updated their networking hype cycle. Not surprisingly:
- Ethernet switching fabrics are on the slope of enlightenment (finally – we’ve been educating networking engineers on what they really are for half a decade);
- SDN is well on its way into the trough of disillusionment (shameless plug: I guess not enough people attended real-life SDN workshops) and whitebox switching is going the same way;
- SD-WAN is nearing the peak of inflated expectations;
- FCoE and Long-Distance vMotion will be dead before they reach the plateau.
One of the participants of the Carrier Ethernet LinkedIn group asked a great question:
When we install a virtual-router of any vendor over an ordinary sever (having general-purpose microprocessor), can it really compete with a physical-router having ASICs, Network Processors…?
Short answer: No … and here’s my longer answer (cross-posted to my blog because not all of my readers participate in that group).