LAS VEGAS With an emphasis on cost per port, Marvell has expanded the low end of its Prestera gigabit switch lineup with the introduction of an unmanaged 8-/16-/24-port device for small- to medium-size businesses. The company has also debuted the Link Street 5- and 8-port gigabit switch for the small office/home office (SOHO) and consumer applications.
Descended from the company's Prestera EX and MX families for the enterprise and metro-access markets, the new Prestera DX strips away many of the control and classification features of those families. However, it still includes fully integrated 4000-address media access control with embedded buffer memory and an integrated RGMII serializer/deserializer (serdes) on each port. It has full wire-speed switching with quality of service (QoS) features that include IEEE 802.1p, DiffServ, and four priority levels per port.
"The 24-/16-/8-port market is the 'sweet-spot' right now," said Tony Hsu, senior product marketing manager at Marvell, "and we're leveraging our switch and physical-layer technology to go after it." Marvell is pairing the Prestera with its Alaska 4-port gigabit PHY and together, according to Hsu, the full solution can come in at $8 per port.
All the switches operate off 1.2 and 2.5 V and include a single integrated 25-MHz clock reference. The 8-port switch (-DX81) consumes 1.5 W, said Hsu, while the 24-port version (-DX241) consumes 3.5 W. Both the 24-port and 16-port (-DX161) are pin compatible.
According to Hsu, the company opted for a four-pin MGMII serdes as an interface to the PHY to avoid the routing and separation issues associated with other interfaces, such as the 12 or 14-pin RGMII interface used in the recently announced 24-port Stapleton family from Vitesse. "With a four-pin interface we can keep the design to four layers, versus six to eight for others," he said. "Two layers can add 25 percent to the cost."
All three devices in the Prestera-DX lineup start sampling in June with production slated for August. While Hsu said he doesn't see an immediate need for a managed solution for the applications the switch is targeting, the company is working on including an ARM7 CPU to allow management functions in the future. For now, an interface to an external CPU is provided.
The devices are manufactured in a 0.15-micron CMOS process. The DX-81 comes in a 128-pin LQFP while the DX161 and DX241 16- and 24-port devices both come in a 458-pin, 31- x 31-mm BGA.
The Link Street 88E6151 and 88E6181 5- and 8-port gigabit switches for home and small office use much the same technology as the Prestera line. However, according to Bill Windsor, director of product marketing for the Link Street family, the differentiation will come in the distribution channels, ODMs and OEMs which will be targeted.
"Our goal with Link Street is to speed time to market and simplify installation," he said.