HP StorageWorks 2/24 FW 07.00.00/HAFM SW 08.06.00 McDATA Products in a SAN Env - Page 187

Implementing SAN Internetworking Solutions 4 SONET and SDH are globally standardized technologies, more widely deployed than dark fiber or WDM, and provide a protected connection between two locations. SONET and SDH rings are also self-healing. This means a link is usually restored within 50 ms of break detection without user intervention. This makes SONET and SDH highly-available services. Generic Framing Procedure (GFP) is a protocol-independent SONET and SDH standard that defines a mapping scheme for storage protocols such as native FCP, FICON, and iFCP. The standard includes a forward error-correction scheme that enables low bit-error rates critical for storage connectivity. Additionally, the protocol mapping to SONET or SDH requires little overhead and has minimal impact on latency and throughput. GFP is deployed with virtual concatenation (VCAT), a standard that increases bandwidth efficiency by flexibly extending bandwidth allocation in 50-Mbps increments. This extends the bandwidth range from 50 Mbps to full Fibre Channel rates. To support storage extension over long distances, GFP provides buffering and flow control to ensure high throughput without the need for Fibre Channel BB_Credit buffering. Figure 4-10 illustrates multiple extended-distance connections through a SONET interface. Figure 4-10 SONET Extended-Distance Connectivity The technology: • Is widely deployed and highly-available, and is well suited as an extension technology for ADR applications over thousands of kilometers. Implementing SAN Internetworking Solutions 4-43