Networking equipment giant Cisco Systems Inc. (Nasdaq: CSCO) is building a router of colossal proportions, according to one source familiar with the product. The behemoth core routing platform supposedly links to up to 18 different chassis, weighs more than 1,300 pounds per chassis, and has a total system capacity of 11.5 Tbit/s.

Sound farfetched? It may well be. Light Reading couldn't independently verify our source's data, but those familiar with Cisco's plans -- analysts and other sources -- say the findings sound authentic based on their past meetings with carriers reviewing the product.

If true, these few details that have leaked out are significant, given that Cisco won't even publicly acknowledge that the product exists. Folks have speculated about Cisco's Huge Fast Router (HFR) for years. Most recently, some were expecting its debut at Supercomm 2003, then again at the International Telecommunication Union's ITU Telecom tradeshow in Geneva.

"We know it’s out there," says Stephen Kamman, an analyst with CIBC World Markets. "Everyone’s just waiting for Cisco to tell us what we already know."

Several analysts say the product is in trials with at least six carriers, two of which are believed to be AT&T Corp. (NYSE: T) and Sprint Corp. (NYSE: FON), and at least one major regional Bell operator.

The long-awaited router is interesting, in part, because Cisco has spent an exorbitant amount of time and money developing the beast, sources say. For example, the company has built an entirely new operating system to run the thing.

Kevin Mitchell, an analyst with Infonetics Research Inc., says that most carriers are still only testing the software. Consequently, he doesn’t expect the product to be commercially deployed for at least another 12 months.

Here are some other details one Light Reading source was able to uncover after reviewing documents that Cisco itself circulated about its product:

Specifics about line-card densities on individual HFR chassis aren't known yet, but its scaleability recalls the Juniper Networks Inc. (Nasdaq: JNPR) T640 core chassis, which was introduced in 2002 (see Juniper Goes Terabit With the T640). At the time, Juniper outlined details of a new optical core it called the TX, which could be used to link together up to eight T640's. Cisco's scaleable router, deployed in a dual-core configuration, can supposedly link together up to 18 different chassis. Even though Juniper has introduced the concept of the TX, it hasn't formally launched the product, nor has it announced any customers that are using it.

"Considering that Juniper hasn’t released the TX core connection for the T640, it's really a matter of just comparing PowerPoint [presentations]," says Infonetics' Mitchell.

Avici is the only vendor that has a working multichassis implementation. The company announced in the second quarter of this year that AT&T had hooked two of its TSR routers together.

Cisco did not respond to requests for comment on this article. — Marguerite Reardon, Senior Editor, Light Reading