Vitesse Extends Life of Legacy Backplanes with Quad 6.5 Gbps Transceiver

3/17/2004 - Vitesse Semiconductor Corporation (NASDAQ: VTSS), announced the VSC1129, the industry’s first quad 6.5 Gbps backplane transceiver with integrated transcoding technology and Forward Error Correction (FEC) capable of transmitting 12.5 Gbps XAUI-based signals over two channels running at just over 5 Gbps each. Utilizing advanced signal processing techniques, the VSC1129 provides up to a 6x increase in effective data throughput across the installed base of chassis and associated backplane hardware. Existing backplanes typically designed for 1 Gbps can be increased to channel rates as high as 6.5 Gbps for a broad range of applications, including high-speed networking, enterprise computing, storage area networking, and metropolitan area networks.

Vitesse Competitive Advantages – Reduced Signal Frequency and Simplified Design
The key to the VSC1129 is its integrated transcoding technology. As signal frequency increases, so does the difficulty in overcoming signal impairments associated with high-speed data transmission such as signal reflection, attenuation, dispersion, and crosstalk. Existing XAUI-based applications, such as 10 Gigabit Ethernet and 10 Gigabit Fibre Channel, today use 8B/10B encoding, but only by adding 25% overhead and requiring 12.5 Gbps aggregate to transfer a 10 Gbps stream.

Using innovative transcoding technology, the VSC1129 strips off the 25% overhead associated with 8B/10B encoding and re-encodes the data using a more efficient structure requiring only 3% overhead. The internal XGMII control information is preserved and reconstructed on the receive side. This comparative 22% decrease in signal frequency directly translates to a reduction in signal impairment, significantly easing backplane design constraints, as well as inherently reducing the BER. Now a 12.5 Gbps data transfer can be consolidated over two channels running at just over 5 Gbps instead of either over four 3.125 Gbps or two 6.25 Gbps links as would be required when using 8B/10B encoding.

Vitesse is the first company to bring FEC technology to 6.5 Gbps backplanes. The VSC1129 has an optional FEC engine, evolved from three generations of optical fiber transport processor development, that operates within the 3% framing structure overhead. FEC enables recovery from link errors during transmission. The FEC improves the effective SNR by 2.5 dB, resulting in a BER better by three orders of magnitude (1000 times) and providing immunity from short error bursts that can often occur in real-world system environments. The VSC1129 also offers an optimal combination of transmit multi-tap pre-emphasis and receive-side feed-forward and decision feedback equalizers (FFE + DFE) for superior channel resiliency.

With four serial transmit and receive channels operating from 5 Gbps to 6.5 Gbps per channel, the VSC1129 provides an aggregate bidirectional bandwidth up to 52 Gbps. The configurable client interface accepts many of today’s high-speed communications protocols, including 10 Gigabit Ethernet, 10 Gigabit Fibre Channel, OC-48/STM-16 SONET/SDH, Serial Rapid I/O, InfiniBand, and PCI Express. Manufactured in a 0.13 micron CMOS technology, the device runs on 1.2 V and 2.5 V, consumes less than 4.0 W, offers a Tx to Rx latency of 40 ns to 450 ns, depending upon mode, and yields a BER of better than 10-15 on typical channels.

Applications for the VSC1129 include multi-gigabit routers, chassis-based enterprise switches, SAN directors and fabric switches, and blade servers. “Line cards based on the VSC1129 can double the effective throughput across today’s XAUI backplanes,” says Glen Koziuk, director of marketing for Backplane Products at Vitesse, “enabling OEMs to protect and extend their existing business through the development of higher density, higher throughput equipment.”

For greenfield installations, the VSC1129 enables the cost-effective development of high throughput systems by easing the performance requirements placed on the printed circuit board and connector technologies. Koziuk noted, “With 0.13 micron CMOS technology, difficult backplane challenges can be solved more cost effectively using a few square millimeters of well designed silicon than by employing exotic connectors, expensive RF-quality board materials, and non-mainstream manufacturing techniques.”

The VSC1129, along with the 6.5 Gbps asynchronous crosspoint switches (VSC3104 and VSC3108) announced in December of 2003, are part of Vitesse’s emerging product roadmap designed to increase backplane transmission rates beyond 11 Gbps.

Pricing and Availability
Sampling in Q2’CY04, the VSC1129 is priced at $175 in low volume quantities and comes in a 400-pin, 21x21 mm plastic BGA package. Development support for the VSC1129 includes an evaluation board capable of being connected to a customer’s backplane through a pass-through card, GUI software, reference schematics, and a full suite of application support materials.

BER: bit error rate
FEC: Forward Error Correction
Gbps: gigabits per second
GUI: Graphical User Interface
OEM: Original Equipment Manufacturer
SAN: Storage Area Network
SNR: Signal-to-Noise Ratio
XAUI: 10 Gigabit Attachment Unit Interface
XGMII: 10 Gigabit Media Independent Interface

About Vitesse
Vitesse is a leading designer and manufacturer of innovative silicon solutions and optical devices used in the networking, communications and storage industries worldwide. Vitesse works to specifically address the requirements of system designers and OEMs by providing high-performance, integrated products that are ideally suited for use in Enterprise, Access, Metro and Core applications. Additional company and product information is available at

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