Back when we first launched Oracle Solaris Express, I stumbled upon a couple hundred bikers who were building a bonfire in the woods with the timber from an old cabin, a dozen cans of gasoline, and a couple of Honda Priuses. To avoid a beating, I convinced them to let me explain how virtual networks work. They set down their gasoline and I rescued some upholstery from the fire.
In the good old days, I explained, a proper biker had only one bike, a hardtail Knucklehead with a kick-starter, 5" over forks, and apes with purty leather tassels fabricated from the remnants of a favorite biker momma's chaps. And one leather jacket. Well worn. Naturally, that proper biker wanted to go to many rallies. But because he only had one bike, he could only go to one rally at a time. And he wore the same jacket to each rally. I suggested they call that favorite leather jacket Solaris, and that hardtail knucklehead a NIC.
"Nick," they asked. "Who's Nick?"
"Well, N-I-C," I explained. "It's short for Network Interface Card."
That made them a little restless, but I quickly added that as a result of the one-jacket, one-bike rule, life was good, pipes were loud, and America ruled the world.
They liked that. I got several pats on the back.
Fast forward 50, maybe 60 years, I explained while drawing the diagram above, and now we call ourselves motorcyclists. We have multiple bikes. And they are all EPA-compliant. And in keeping with the sartorial splendor of the court of Louix the XIV, we have one outfit for each bike. I asked them to pretend that each outfit was a zone, and each motorcycle was a virtual NIC, or VNIC. They got restless at the mention of Nick again, particularly after I brought up France, but I held up a well-manicured hand so they would allow me to elaborate. When modern motorcyclists like me want to go to Sturgis, I explained, we get into our Sturgis zone (a 5-day shadow, leather chaps, and obligatory bandana), and throw a leg over our Sturgis VNIC (a blinged-out CVO Harley Davidson 110" Ultra Classic with the dual-tone paint job). When we want to go to Americade, we slip into our Americade zone (a clean shave, a heated vest, and a reflective yellow Aerostich waterproof suit with 10 large pockets), and hop onto our Americade VNIC (a BMW K1200LT with heated seats, cup holder, and GPS). And so on. One outfit for each motorcycle, one zone for each vnic.
That's as far as I got. They gave me a beating and tossed me, my Vespa, and my modster jacket into the lake.
I decided to get some help.
Nicolas Droux, who was part of the engineering team that developed network virtualization (project Crossbow), agreed to explain all this to me. After assuring me that he was not a biker, we got on the phone. And we turned our phone conversation into a nifty podcast.
This podcast is easier to absorb if you listen to it in two parts, each about 15 minutes long.
In the first half, Nicolas explains how the process of managing network traffic for multiple Solaris zones across a single Network Interface Card (NIC) naturally led to the development of virtual NICs. And then to the network-in-a-box concept, which allowed you for the first time to create complete network topologies and run them within a single host to experiment, simulate, or test.
In the second half, Nicolas provides more details about combining zones and VNICS to create a test environment. He explains how you can create a zone to function as a virtual network router, for instance, or a virtual load balancer. By isolating these network functions into zones, you can test how your application performs with different settings, and use DTrace to follow the application calls as they are routed through your virtual network. Once you have the optimum settings for the network and the application, you can deploy it in your data center.
Here are some more resources to help you understand network virtualization:
- Rick Ramsey