6:15 PM -- When the Nexus 7000 came out, every competitor zoomed in on the same factor: Cisco Systems Inc. (Nasdaq: CSCO) had to introduce a new operating system with the box.

Cisco already has multiple versions of its Internetwork Operating System (IOS) floating around its installed base. It had introduced another, IOS-XR, for the CRS-1 core router, and acquired SAN-OS by buying Andiamo. And here was yet another OS to juggle. (See Cisco's Nexus Targets Data Center's Future.)

Cisco has since fired some comebacks at its competitors, mainly Juniper Networks Inc. (NYSE: JNPR). Speaking at the Cisco Partner Summit on Tuesday, Doug Gourlay, Cisco's senior director for data center products, responded to a question about operating systems:

Translation: It's not worth the time to make sure everything runs on the same OS. Gourlay followed that up with:

That's great, but Cisco built the Nexus 7000 by itself, and officials say they knew from square one that they'd have to build it with a new OS. It's not an acquisition story, regardless of the Nuova deal.

Moreover, Juniper agrees with Gourlay's points. That's why the ERX series and the Netscreen boxes have maintained their respective operating systems, without a goal of unifying them all.

Go back to the beginning: The dig against Cisco has always been that that it's taken one operating system and splintered it into dozens of versions. Prodding Cisco for NX-OS might be unfair, then -- but so is a comparison between Cisco's and Juniper's multiple OSs. Junos, the Juniper equivalent to IOS, still comes in a single flavor that's updated on a strict schedule.

Then, of course, you've got Alcatel-Lucent (NYSE: ALU). The former TiMetra, now AlcaLu's IP division, has only built one box and keeps adding to or subtracting from it. So by definition, it's really got only one OS.

— Craig Matsumoto, West Coast Editor, Light Reading