Arista is hoping to drastically expand its reach in the enterprise market with a one-tier architecture based on new switches being announced Monday.

The company has made its mark in data centers and financial-trading networks, especially with high-density, low-latency gear. Now it's going after more normal networks. Specifically, it's targeting the Catalyst 6500, the mainstream heart of Cisco's lineup.

Collectively named the X-series, the new switch lines are the 7300 line of modular switches and the 7250X fixed-configuration switches.

Arista has spent five years pushing the two-tiered leaf-spine architecture in data centers, a collapsing of the top-of-rack/aggregation/core setup that had been common. Now it wants to merge the leaf and spine into a one-tier architecture the company is calling a "spline." (Suggested motto: "Hey, it's better than 'speaf.'")

Near as we can tell, the spline is not named after polynomial functions nor after fleshy, spherical aliens.

The spline is deployed by putting switches in the middle of a row, where it speeds up (or at least simplifies) traffic between racks, because every endpoint is one hop away from all others. Intended to connect up to 2,000 servers, the spline is a smaller-scale alternative to the leaf/spine architecture, which was designed to let operators expand cloud networks by just attaching more server racks to the spine. Here, expansion comes by adding more line cards to a rack.

In that sense, the spline gives Arista a pitch for normal-sized networks. "I don't believe the data center would use the spline at all. This is for the enterprise that has not moved to the next-generation data center," says Anshul Sadana, a senior vice president at Arista.

"It all comes down to density. You can't say everybody is Facebook or Google," says Christian Renaud, an analyst with 451 Research.

(Renaud points out that Arista must already be selling substantially to enterprises, because he doubts that data centers alone could account for Arista's revenues -- which should exceed $300 million in 2013, according to analyst Brian Marshall of ISI Group, quoted in Barron's.)

If Arista is going after the wider enterprise market at all, it should follow these first X-series switches with a lot more, to cover more of the market, Renaud says. "Jayshree's not dumb. If she's going to get in that market, she's going to do it in a big way, not go whimpering at the back door," he says.

The 7250X series are fixed-configuration boxes. Arista is announcing only one in this family: The 7250 QX-64, a box 2 rack units high that can support 64 40-Gb/s ports or 256 10-Gb/s ports.

The 7300X series, due to ship in the first quarter of 2014, are the modular switches for the spline, with models fitting four, eight, or 16 line cards. The largest, the 7316, can support 512 40-Gb/s ports or 2,048 10-Gb/s ports in half a rack, Arista says.

That's apparently Arista's highest-density switch, beating out the 7508 spine switch, which can fit 288 40-Gb/s ports or 1,152 10-Gb/s ports. But that doesn't push Arista's 7500E out of a job, Sadana says.

That's because the 7316 is less advanced. The 7500E has almost 100 times more memory, for example — literally. It can hold 144 GBytes worth of packet buffers compared with the 7316's 384 MBytes.

The 7500E is also intended for users that are more obsessed with not losing packets. It uses cell-based switching internally, eking out every last bit of efficiency by avoiding any collisions. The 7300 doesn't quite go that far. It uses bandwidth-aware load balancing internally, assigning new flows to underutilized fabric links, but that still ranks at about 90 percent efficiency compared with what the 7500E does, Sadana says.

The spline switches are based on Broadcom's Trident II chips.