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©2004 Vitesse Semiconductor Corporation

Barrington™ – 24x10/100/1000 Ethernet MAC with SPI-4.2 System Interface

VSC7324

The Barrington family is based on Vitesse’s third

generation MAC architecture and includes the

flagship 24-port VSC7324, the 16-port VSC7325,

and the 12-port VSC7326. Each device has

advanced traffic over-subscription mechanisms

to ensure quality of service and high bandwidth availability

during periods of peak network utilization. Combining this

capability with extensive per port buffering, high-density

platforms such as Ethernet switches and routers can aggregate

up to 24 Gigabit Ethernet ports into a single 10 Gbps packet

processor. OEMs realize a substantial cost savings by reducing

system cost per user without impacting network performance.

Barrington (VSC7324) is an advanced 24-port Triple Speed

Ethernet MAC solution with Intelligent Over-subscription

enabling low cost, high-density, chassis-based linecards

ranging from 24 to 96 ports. Barrington, which is also available

in 12 and 16 port versions, is a versatile building block for a

range of high-density triple-speed Ethernet applications in the

Enterprise, Metro, and Core. Barrington integrates 24 triple-

speed MACs, advanced over-subscription mechanisms, an

extensive on-chip memory system, an OIF compliant SPI-4.2

interface with support for dynamic deskew, both a 16-bit

parallel and a 4-wire serial CPU interface, and dual MII

Management interfaces.

As the transition to triple-speed copper interfaces in the

Enterprise increases, the need for intelligent over-subscription

and control traffic protection functionality is critical to

efficient network operation and management. The Barrington

family includes advanced over-subscription mechanisms,

used to control the bandwidth on each Ethernet port in order to

prioritize traffic across all 24-ports. As part of the advanced over-

BLOCK DIAGRAM:

GENERAL DESCRIPTION:

prioritize traffic across all 24-ports. As part of the advanced over-

subscription mechanisms, the Barrington family also prioritizes and

protects Layer 2 and Layer 3 control frames to maintain overall network

management and efficiency during periods of peak network utilization.

Interfacing to the triple-speed MAC ports is accomplished using

the reduced pin count Reduced Gigabit Media Independent

Interface (RGMII).

On the system side Barrington utilizes an

industry standard SPI-4.2 system interface with 24 channels.

The internal ingress (Rx) and egress (Tx) FIFOs, which are

provisionable on a per-port basis in increments of 2 kB, are

capable of handling short-haul flow control and accommodating

bursty traffic between the Ethernet MACs and the SPI-4.2 system

interface. The FIFO structures are independently configurable for

either cut-through or store-and-forward modes.

The Barrington Family is supported in Vitesse’s MAC Application

Software (MAS) suite. The MAS is a library of generic ANSI C

functions for various Gigabit Ethernet (GbE) and Ten Gigabit

Ethernet (10GbE) Media Access Controllers in the Vitesse MAC

family.

The MAC Application Software provides a common

software solution for the Vitesse MAC family beginning with

Meigs-II™ and including Meigs-IIe™ and Campbell-I™. The MAC

Application Software simplifies the use of these MAC devices by

providing a well defined, operating system and processor

independent application-programming interface (API).

The Barrington Family is supported by a comprehensive collateral

package including application notes, IBIS models, DSDL file,

reference schematics, symbols, and University of New Hampshire

(UNH) Interoperability Lab (IOL) reports for Fast Ethernet and

Gigabit Ethernet test suites.

SPECIFICA TIONS:

1.8V Core Power Supply

2.5V & 3.3V Interface Power Supply

741 Calle Plano

Camarillo, CA 93012, USA

Tel: +1 805.388.3700

Fax: +1 805.987.5896

www.vitesse.com