The morning after VMware Inc. announced its intended $1.2 billion acquisition of network virtualization company Nicira Networks Inc., my email inbox was packed with notes from giddy software defined networking players with two messages: 1. Cisco Systems Inc. is in big trouble. 2. SDN is here to stay.

What's clear is that VMware's acquisition of Nicira validates the future of SDN as a technology. That's important, considering SDN was more vendor vision than actual product until recently. Nicira's staggering sale price "puts a dollar value on the space," said Eric Hanselman, research director at 451 Research.

Whether Cisco is now facing mega trouble is less clear. It's probably fair to say that Cisco isn't in immediate danger but soon will be under the gun to lay out a much clearer SDN vision than the