HP A7446B Converged fabrics: Emerging technologies for simplifying data center - Page 3
Converged fabrics with 10 Gigabit Ethernet
UPC - 882780355118
View all HP A7446B manuals
Add to My Manuals
Save this manual to your list of manuals |
Page 3 highlights
Converged fabrics with 10 Gigabit Ethernet One obstacle to using Ethernet as a basis for converged fabrics has been its limited bandwidth. As 10GbE technology becomes more widely implemented, HP expects 10GbE network components to fulfill the needs of applications that require either the 10GbE bandwidth or its low-latency benefits. With the emergence of 10GbE, a unified Ethernet switching fabric for all data center applications is expected to serve as the basis for future data center consolidation and architectural evolution. With Ethernet and Internet Protocol (IP) as the unified switching fabric, administrators will also have maximum flexibility in selecting network management tools. As Ethernet bandwidth increases, fewer physical links can carry more data (Figure 1). Figure 1. All traffic types sharing the same link Currently, two of the most promising transport standards for converged fabrics are Internet Small Computer System Interface (iSCSI) and FCoE. iSCSI iSCSI follows the SCSI architectural model, which is based on message exchange between an initiator and a storage resource, or target. iSCSI initiators access targets using the iSCSI protocol. While the target is usually a drive enclosure or another computer, it can also be any other storage device that supports the iSCSI protocol, such as a tape drive. The iSCSI stack at both ends of the path encapsulates SCSI block commands into Ethernet packets for transmission over IP networks. Figure 2 illustrates a message exchange between an initiator and a target. The process begins when an application sends a request to the operating system (OS) to read or write data. The OS generates the appropriate SCSI commands and data request in the form of a message. Before the message can be sent over an IP network, it is processed through iSCSI to encapsulate the request into the Transmission Control Protocol over Internet Protocol (TCP/IP) protocol stack (attaching routing, error checking, and control information) for transmission over the network. This can be accomplished using driver-level or OS-level software, or it can be offloaded to the host bus adapter (HBA). The HBA transmits the packets over the IP network. When the packets reach the target device, they go through a reverse process to reassemble the data, which is then moved to the SCSI controller. The SCSI controller fulfills the request by writing data to or reading data from the target device. For a read transaction, the target returns data to the initiator using the iSCSI protocol. 3