Sources on Friday were suddenly buzzing that a major software-defined networking (SDN) acquisition is imminent. Mashing the theories together, we have: Big Switch Networks or Pluribus is supposedly going to be bought by a big OEM either Monday or Tuesday.

We're digging for more specific information, including who the buyer would be. (PLUMgrid's name had come up as well, but a source-who-would-know hadn't heard of anything in the works.)

A major SDN deal wouldn't be so surprising at this juncture. One interesting twist in SDN's short history was that once a few startups emerged — Big Switch in particular — the big OEMs ran off to build their own SDN strategies.

Cisco and Alcatel-Lucent set up their own "SDN" shops, namely  Insieme, which was reportedly a different project converted to the SDN cause, and Nuage Networks. HP went all-in with OpenFlow, attaching it to all its switches. And Brocade built up an architecture starting from the Vyatta open-source router, casting its lot with OpenDaylight more enthusiastically than most others.

The exception is Juniper, which, from what we were told, resisted SDN and then, when the company capitulated, snubbed its internal projects in favor of acquiring Contrail Systems.

Consider those to be first-round attempts at SDN empire-building. Most of them have had some time to settle and to be digested by key customers — Insieme, for instance, got launched last November, but you know some big customers were privy to the plan much earlier than that.

As one vendor executive pointed out to me Friday, that means it could be time to start patching holes in these strategies. That's when the checkbooks would come out.

Now for the rampant speculation.

HP, with its server heritage, could well be interested in Pluribus, which combines switching and compute into one entity. But it's intriguing to think HP might acquire Big Switch. Both companies bet big on OpenFlow at first, and both are having to rethink strategy now that overlay networks have stolen most of the SDN thunder.

That's not as big a deal to HP. Big Switch, though, had to refocus beyond building an OpenFlow controller; it's expanded that story to encompass software for bare-metal switching. Now that its Big Cloud Fabric is shipping, Big Switch might make an interesting acquisition candidate for a company looking at OpenFlow Phase II. (Big Switch declined to comment for this story.)

While I'm at it, I might as well mention: It sure seems like Embrane ought to get bought by Cisco eventually. Founding CEO Dante Malagrinò came from Cisco, which invested in the startup earlier this year. One glitch in the theory is that Malagrinò stepped aside earlier this year for a CEO without Cisco ties. I don't think this deal would be the source of Friday's rumors.

What combination do you like? Juniper and Big Switch? HP and PLUMgrid? Colonel Mustard in the Hall with the Candlestick? Let us know in the comments.