BROCADE IP PRIMER

Chapter 3: Data Center Bridging (DCB)Operating Systems/ApplicationsSCSI LayeriSCSI FCP FCPTCPIPEthernetiSCSIFCoEDCBFibre Channelover EthernetFCFibre ChannelThe changes, or enhancements, made to Ethernet as part of the DCB effort tosupport convergence do not prevent the simultaneous deployment of a TCP/IPstack. More importantly, since the new lossless Ethernet can be beneficial tothe flow control aspects of TCP/IP, the lossless behavior of the new Ethernetcan be turned on or off for LAN TCP/IP traffic. That means that data center professionalscan deploy LANs using all of the following on one convergedmedium:• Traditional Ethernet, lossless• Ethernet with DCB features• Fibre Channel over Ethernet (FCoE) with DCB features enabled (the FCoEprotocol enables the transport of FC storage traffic over a new losslessEthernet medium)The combination of DCB and FCoE technologies provides a solution for thechallenges of physical infrastructure reduction and cabling simplicity. Subsequentsections describe how this was accomplished. OK, this standards stuffis pretty dry but on some level, it’s all about the standards.IEEE—Data Center BridgingThe Data Center Bridging (DCB) effort undertaken by the IEEE 802.1 work groupadds new extensions to bridging and Ethernet, so that it becomes capable ofconverging LAN and storage traffic on a single link. Often, you hear that new DCBfeatures will make Ethernet "like Fibre Channel." That’s true, because the newfeatures being added to Ethernet are solving issues that FC faced in the pastand successfully resolved. IEEE is expected to complete its work on the componentsof DCB by the end of 2010. The new enhancements are PFC, ETS, andDCBX.76 Brocade IP Primer