Vitesse Enables Breakthrough Migration of Legacy Fibre Channel Storage Hardware to 8G

Vitesse Semiconductor Corp. has launched the VSC8238-02 EDC clock and data recovery (CDR) device, the newest member of its family of ICs featuring its FlexEQ Electronic Dispersion Compensation (EDC) technology. Delivering the most powerful signal integrity solution available on the market today, the VSC8238-02 meets the challenges of transmitting and recovering 8G Fibre Channel data in lossy legacy blade server backplanes and host bus adapters (HBA). Additionally, the VSC8238-02 is backward compatible with 2G and 4G Fibre Channel for legacy backplane data rate upgrades.

“Vitesse’s VSC8238-02 EDC CDR solution is taking the migration of legacy Fibre Channel storage hardware to a new level,” said Gary Paules, product marketing manager for Vitesse. “As the need to overcome bandwidth demands on the data center grows increasingly common, the ability to double or quadruple the data rate quickly and cost-efficiently has become imperative. Our new device provides field-proven 8G operation with unique backward compatibility to effectively address this critical technical challenge for the first time.”

Vitesse’s VSC8238 exceeds the IEEE Long Range Multimode (LRM) requirement of 220m. Incorporating sophisticated feed-forward equalization (FFE) and decision feedback equalization (DFE) architecture, the VSC8238 has defined and embodied superior performance margins in excess of 3dB in relation to all LRM standard requirements. Now, the same performance advantages seen in optical transport applications are being applied to electrical backplane upgrades that are underway in many systems: 4G to 8G in Fibre Channel; 3G XAUI to 10G Ethernet; and 5G DDR to 10G QDR in Infiniband.

During upgrades of legacy hardware, all must overcome high insertion losses, excessive signal crosstalk, degraded signal to noise ratios, and significant signal reflections due to lossy printed circuit boards and subrate connectors. The adaptive nature of the VSC8238-02 FlexEQ architecture allows it to compensate for widely disparate channels unlike simpler equalizer devices and operate in very poor noise environments below 20dB Signal to Noise Ratio (SNR). The highly linear input Automatic Gain Control (AGC) provides a constant signal level to the equalizer independent of the channel loss that can vary greatly from channel-to-channel and from one chassis generation to the next. The device provides in excess of 5UI of correction to resolve high-level signal reflections that can occur on the shorter channels of legacy platforms. Unlike DSP-based solutions, the VSC8238-02 minimizes system latency critical to data center and storage applications.

In addition to supporting the data rate increase in a legacy low speed platform, the need to continue supporting lower data rates is a critical requirement. Vitesse, together with QLogic and Emulex, have overcome this very challenging auto-negotiation requirement via firmware development. As a result, the VSC8238-02 supports 2G, 4G, and 8G traffic with convergence times of 50ms, well within the stringent 150ms Fibre Channel requirement.

Vitesse VSC8238-02 EDC

Vitesse