Despite all the hoopla over network processors, they just aren't making much money yet. Meanwhile, there's another processor market that's less glamorous but more lucrative.

Control-plane processors are a high-end offshoot of the mainstream microprocessor market, and, in networking alone, they tallied about $250 million in sales last year.

PMC-Sierra Inc. (Nasdaq: PMCS) continues to hold an upper hand in the market, although it's left room open for competitors to sneak in, according to "A Guide to Control-Plane Processors," a report being released later this week by The Linley Group.

Because control-plane processors get lumped into other microprocessor sales, it's tough to get exact market figures. But PMC appears to be leading with roughly $75 million in processor sales last year, says Bob Wheeler, analyst with Linley.

A control-plane processor is just a really big microprocessor. Like a Pentium, it acts as the brains of a system and executes the operating system. Being microprocessors, they can be used in applications beyond networking -- laser printers are a big market, for example.

The market falls into two types of processors. PMC and Broadcom Corp. (Nasdaq: BRCM) use the MIPS architecture, which is licensed out by MIPS Technologies Inc. (Nasdaq: MIPS). Both got into the game via acquisitions, with PMC purchasing Quantum Effect Devices Inc. (QED) and Broadcom acquiring SiByte Inc. (see PMC-Sierra to Buy Quantum for $2.3B and Broadcom's on a Buying Spree).

MIPS's traditional rival is the PowerPC architecture, with parts sold by IBM Corp. (NYSE: IBM) and Motorola Inc. (NYSE: MOT).

MIPS continues to rule the market for two reasons. First, it's got a headstart. High-end switch/router architectures favored MIPS in the past. Moreover, Cisco Systems Inc. (Nasdaq: CSCO) made QED the processor of choice for its IOS software. "MIPS chips have definitely dominated at the high end," Wheeler says.

Cisco has ported IOS to the PowerPC, he says, so the wealth could get spread out a bit. But then, PowerPC has a second handicap -- it consumes too much power for many switch and router environments. That's because the PowerPC was designed for personal computing, its biggest application being the (dare we mention it?) Apple Computer Inc. (Nasdaq: AAPL) Macintosh.

Within the MIPS camp, PMC has the upper hand over Broadcom. QED is an older company and thus has a larger fan base. Moreover, the SiByte chip didn't quite live up to the gigahertz promises made just before the acquisition, Wheeler says.

Coincidentally, Broadcom just today pointed out that SiByte's chip has landed in several dozen designs (see Broadcom Claims 100 SiByte Wins). But none of the announced wins match up to a Cisco. "They're mostly second-tier and lower. Probably the most important ones are a Redback design win and a Samsung DSLAM design win," says Wheeler.

That's not to say PMC will reign forever. One area where the PowerPC camp is gaining some ground is integration. Most of the PMC processors still require an external system controller -- usually the Discovery chip sold by Marvell Technology Group Ltd. (Nasdaq: MRVL). By integrating that part -- as Motorola has begun to do -- one could speed up the processor a bit and save power and space to boot.

"PMC has been kind of slow to respond to that trend, outside of the RM9000," Wheeler observes. "That's left kind of an opening for Motorola and IBM at the midrange and Broadcom at the high end."

Other vendors such as Integrated Device Technology Inc. (IDT) (Nasdaq: IDTI) and NEC Corp. (Nasdaq: NIPNY) make control-plane processors but don't have much impact on the networking market, Wheeler says. Advanced Micro Devices (NYSE: AMD) has an entry here with its Alchemy chips, and Intel Corp. (Nasdaq: INTC) has tried selling Pentium and XScale processors into lower-end control-plane applications.

— Craig Matsumoto, Senior Editor, Light Reading