XFP progress casts doubt on the future of other modules

Observers point to the evolution of the OC-48 (2.5-Gbit/sec) module market—which started with transponders and now sees transceivers making gains in all applications but long-haul—as an illustration of where the 10-Gbit/sec market will head. Thus, they say, many applications that 300-pin transponders (and, in the datacom world, XENPAK) now serve will shift to transceivers such as XFP. The question in their minds is, when will this change occur—and will it happen quickly enough to sweep the XPAK and X2 off the playing field before they even enter the game?

Vendors that support more than one MSA appear divided on the question. For example, Merge Optics (Berlin) markets X2 and XFP devices. But Dag Neumeuer, the company's chief executive, sees only "limited activity" for the X2 and its XPAK competition as system houses switch quickly from 300-pin transponders to XFP transceivers. On the other hand, Howard Pan, senior product manager in the Optical Platform Division of Intel's Communications Group (Newark, CA), predicts success for his company's XPAK and XENPAK modules, with XFP a long-term option for designers.

Ed Cornejo, director of product marketing at Opnext (Eatontown, NJ), agrees with Pan that there's room for a variety of 10-Gbit/sec devices. To illustrate this point, Opnext announced at March's OFC that its 10-Gbit/sec line will include 300-pin, XENPAK, X2, and XFP options.

Pan and Cornejo base their predictions on the fact that several system houses have already designed boards using the XAUI interface common to XENPAK, XPAK, and X2. XFP uses a 10-Gbit/sec serial interface called XFI. Thus, the question of when system houses will revamp their board designs to replace XAUI with XFI or design new products with XFI at the start should prove the deciding factor in determining whether X2 and XPAK will have their moments in the sun.

Cisco Systems' Catalyst 6500 system, for example, uses XENPAK transponders. The company has passed the word to the module community that it wants to use X2 devices for its next round of enterprise systems. Cornejo believes it will be another three or four design cycles—and at least that number of years—before Cisco decides to revisit these decisions.

Still, the change from XAUI-based board designs to XFI has already begun, according to Steffen Koehler, vice president, marketing at XFP vendor Ignis Optics (San Jose, CA). "By and large, new designs are all looking at XFP. And I don't see the X2s and XPAKs winning a lot of new business. They're capitalizing on the business they've won in the last year," he claims.

One way to speed the transition to XFP would be to incorporate XFI support within the Layer 2 chips for which board space is already reserved. Pan doesn't see that happening until 2004 or 2005. But for designers who have a few square millimeters of extra space, chip companies have begun to roll out XAUI-to-XFI bridge devices. For instance, Aeluros (Mountain View, CA) says its new Puma IC transceiver will provide such a bridge. Meanwhile, BitBlitz Communications (Milpitas, CA) also has released a quad XAUI to serial 10-Gbit/sec transceiver IC, the BBTX400. Intel also has an XAUI-to-serial device, the LXT12101.

However, Cornejo sees plenty of life in competing modules. "We have actual demand, we have actual orders on most things," he says. "And that's why we're working on what we're working on."

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