One of my readers couldn’t figure out how to combine Link Aggregation Groups (LAG, aka Port Channel) with OpenFlow:

I believe that in LAG, every traditional switch would know how to forward the packet from its FIB. Now with OpenFlow, does the controller communicate with every single switch and populate their tables with one group ID for each switch? Or how does the controller figure out the information for multiple switches in the LAG?

As always, the answer is “it depends”, and this time we’re dealing with a pretty complex issue.

Last week we finished the last session of vSphere 6 Networking Deep Dive webinar – 6 hours of downloadable videos covering every single vSphere 6 networking topic are waiting for you.

As always, you get access to the webinar with your ipSpace.net subscription, or you can buy just this webinar, or one of the bundles that include it: Data Center track or Data Center Trilogy.

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.

Another question I got in my Inbox:

What is your opinion on NAC and 802.1x for wired networks? Is there a better way to solve user access control at layer 2? Or is this a poor man's way to avoid network segmentation and internal network firewalls.

Unless you can trust all users (fat chance) or run a network with no access control (unlikely, unless you’re a coffee shop), you need to authenticate the users anyway.

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.

Several of the conversations I had at the recent RIPE70 meeting were focused on career advice (usually along the lines of “which technology should I focus on next”) and inevitably we ended up discussing the benefits of T-shaped skills versus I-shaped skills… and I couldn’t resist drawing a few graphs illustrating them.

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.

Hank left a lovely comment on my Rearchitecting L3-Only Networks blog post:

What you describe is literally intra-area routing in CLNS.

He’s absolutely right (and I admitted as much during my IPv6 Microsegmentation presentations @ Troopers 15).

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.