Nuage Networks, the Alcatel-Lucent subsidiary, is augmenting its software-defined networking (SDN) architecture by adding a gateway — a physical, touchable, droppable box — that reaches out to physical networks, including bare-metal switches.

It's the piece that rounds out Nuage's network virtualization offering and makes it truly end-to-end, says Dimitri Stiliadis, Nuage's CTO and chief architect.

It's also something that's been in the works for two years. Nuage officials are emphasizing that the gateway has always been considered as a part of their Virtualized Services Platform (VSP); it's not a last-minute kludge. (Although with a fourth-quarter shipment target, it's arriving a little later than the other pieces, which began shipping in May.)

The 7850 Virtualized Services Gateway, Nuage's first hardware product, is based on a merchant switch chip, but it's far from a white box. It supports 96 10G ports, a density so high that the faceplate didn't have room for the Nuage logo, officials say.

The idea of reaching physical endpoints has gotten a lot of attention in SDN circles lately. It's why VMware lined up a clutch of hardware partners to go with the NSX announcement in late August; most of them were switch vendors talking about NSX's ability to provision a network connection into their gear.

The 7850 supports multiple encapsulation formats and the Open vSwitch Data Base management protocol (OVSDB), which is what VMware's NSX controller uses to configure hardware switches.

A white-box switch could serve as the gateway, but the 7850 offers several extras. Possibly most important is that the 7850 handles Layer 3 routing, which comes in handy for creating virtual-network connections that cross subnets.

White boxes don't do Layer 3 because their off-the-shelf switch chips don't. To get around that, Nuage added the technology itself; whether via software, an FPGA, or magic pixie dust, the company isn't saying.

Nuage also outfitted the 7850 with a Linux sandbox for housing applications — a security monitoring app or a troubleshooting script, for instance. It's another distinction from a white-box switch, although Stiliadis thnks it's a trend that will be spreading. "You start treating these gateways as servers, not as network elements," he says.

Of course, rather than use a 7850 or a white box, one could use an all-software gateway running in a virtual machine. Nuage already offers that with its VRS-G module. But this becomes impractical for large installations, where that virtual machine needs to handle bandwidth levels of 10G and higher; the resulting server costs, in power and money, vastly outrun those of a white-box switch, Stiliadis says.