Cisco Systems Inc.'s (Nasdaq: CSCO) super core router, dubbed the HFR, isn't commercially available yet, but the beast already has an offspring.

Even while Cisco is out talking to analysts far and wide about its upcoming HFR announcement, now expected between late May and the beginning of Supercomm, Light Reading has learned that another router -- a half-size version of the HFR -- is in development.

The strategy, say sources familiar with Cisco's plans, is to do something similar to what Juniper Networks Inc. (Nasdaq: JNPR) did when it released its T320 router last summer (see Juniper Shrinks Its SuperCore Router). Juniper's T320 is half the capacity of the company's biggest core router, the T640, while still having more horsepower than its older M160 core line. It gave customers something between the limited M160 and the monstrous T640.

In 2002, Avici Systems Inc. (Nasdaq: AVCI; Frankfurt: BVC7), another big-iron competitor of Cisco's, found it could grab a larger router market share by building a behemoth, then scaling it down proportionally (see Avici's Incredible Shrinking Router).

For Cisco, the plan appears to be the same. The upcoming HFR will address the largest of the large core networks, such as the one run by Sprint Corp. (NYSE: FON). But the HFR may be too large for many current Cisco 12000 series customers looking to upgrade. They'll need something in between the 12000 series, but not necessarily as large as the 6 Tbit/s of capacity that the HFR provides (see Cisco Sprints Ahead With HFR).

The Son of HFR will be noteworthy in that, like HFR, it will run Cisco's new routing software. The project has been through several names, sources say, a testament to the stop/start attempts at revamping IOS, Cisco's routing code. At one time, the half-rack router was called "Half Q," according to a source close to Cisco.

Whatever it's called, the new, modular, more stable IOS will be a welcome addition to Cisco's routing family. One of the knocks against IOS in the past has been its lack of consistency across product lines.

"Cisco’s IOS is not one consistent piece of code -- it’s a brand," wrote Geoff Bennett in a Heavy Reading analysis of Cisco last year. "Any code that Cisco acquires is immediately branded as IOS, regardless of the functions, user interface consistency, etc."

Consistent code and scaleable code, however, are two different things. And, while Cisco is adept at building larger and larger routers, it faces a challenge in bridging the gap between its coming HFR and its aging 12000 series.

"The main question from here will be can they scale the box down to put out a 'Son of HFR' -- the equivalent of Juniper's T320 to its T640," says Stephen Kamman, an analyst at CIBC World Markets. "Cisco's GSR [Gigabit Switch Router] series is getting long in the tooth, and we'd look to the HFR platform for a replacement."

Cisco declines to comment on its unannounced products.

— Phil Harvey, News Editor, Light Reading