Picking a "Top 10" in software-defined networking (SDN) is a dangerous business, because the whole sector is in flux. Some major players' products aren't even finished (ahem), and while carriers are interested, it's too early to say how widespread an effect SDN will have.

But with so many vendors jockeying for position, we decided to take a stab at ranking them and even got carried away and included 11 entries. We tried to give extra weight to carrier-minded efforts, although those are still quite the minority.

Here's our take. Be sure to let us know what yours is. And remember, this could all change tomorrow.

1. OpenDaylight
Yes, it's cheating to put a non-company atop the list, but the OpenDaylight consortium consists of theoretically everyone, thanks to the peace/love/freedom of open-source code. The reality is less harmonious, of course. Big Switch Networks (see below) has already pulled back from the consortium, and there's a lingering suspicion that corporate politics could taint OpenDaylight's SDN framework. For now, everybody will be watching OpenDaylight for any sudden moves.

2. VMware/Nicira
The touchstone for overlay-based networking, Nicira Networks Inc. started by relying on OpenFlow, then changed its mind for purposes of scaling. As Nicira gains traction, VMware Inc. becomes more of a foil for Cisco.

3. Juniper/Contrail
Juniper Networks Inc. is trying hard to get its name blended into the SDN discussion. Most of its talk has been closer to network functions virtualization (NFV), but on the SDN side, it's acquired Contrail, a startup whose primary focus was to bring OpenFlow up to a scale suitable for carriers. Using standard protocols -- BGP and XMPP -- Contrail is pitching a distributed control plan that's analogous to the Internet's distributed routing table. Nuage Networks, the Alcatel-Lucent subsidiary, has a very similar plan -- so similar, in fact, that we docked them points for coming on the scene later than Contrail.

4. ConteXtream
You have to give credit to a company that's already got Comcast Corp. and Verizon Communications Inc. interested. Both are investors, and one of them appears to be a customer.

5. Big Switch Networks
The OpenFlow startup seems like a veteran on the scene now. Big Switch Networks's spotlight has been stolen by OpenDaylight for the moment, but the battle goes beyond the OpenFlow controller. While trying not to antagonize equipment vendors, Big Switch has made some moves toward helping white-box switches take more of the network.

6. Cyan
You've seen that 3D diagram of multilayer network modeling, right? If not, Cyan Inc. will be happy to show it to you, over and over. Admittedly, it's pretty cool, and it shows a level of software capability that was an early example of SDN. Those capabilities have attracted more than just attention.

7. Alcatel-Lucent/Nuage
As noted, we're giving Contrail credit for getting an earlier start on carrier-grade scaling. But Nuage has the power of Alcatel-Lucent's router division behind it. Given what that team has accomplished, and the fact that Nuage CEO Sunil Khandekar comes from there, it's hard to dismiss AlcaLu.

8. Cisco/Insieme
You can't ignore the presence of Cisco, especially since it's providing some seed technology for the OpenDaylight SDN controller. Cisco has also articulated a strategy around using APIs to program its own equipment. But saying something about Insieme's actual products might have elevated Cisco on this list. Maybe next time.

9. Plexxi
The team at Plexxi has an entire network planned, not just the architecture. You don't need to use every piece, which is the only prudent way to do this kind of thing, but it still means Plexxi's potential might take a while to reveal itself. Its concept of affinities -- combinations of network elements that a given application needs to use -- also seems to be getting co-opted by Insieme.

10. Ciena
Infinera Corp. is going to carp about being left off the list, but when it came to picking a transport-network representative, we liked Ciena Corp.'s installed base and deeper history with Layer 2. Either company could have made it here, though. The optical network is very much part of the SDN story, and both companies are working in standards bodies to make it happen.

11. Brocade/Vyatta
The market reach of Brocade Communications Systems Inc. can't match Cisco or VMware, and the buzz generated by Vyatta, the virtual-router startup, never got to the levels of Big Switch. These guys aren't an obvious choice to conquer the world, but everyone seems intrigued by what Brocade could do with Vyatta. For being worth watching, Brocade gets the wild card entry.

— Craig Matsumoto, former Managing Editor, Light Reading