Data Center Ethernet

Data center environments have two infrastructures currently. Servers in the data center are connected to the local area network (LAN) and storage area network (SAN) infrastructures. Fibre Channel over Ethernet (FCoE) provides a mechanism to transfer both fibre channel and network traffic over the same unified Ethernet fabric.

Servers connect to the LAN infrastructure through at least two Gigabit Ethernet (1Gbps) network interface cards (NIC) teamed together to provide redundancy and higher throughputs. Most high performance computing servers have six to ten Gigabit Ethernet interfaces to provide adequate throughput to the server. The Cisco 6500 series switch has been the most popular LAN switch in data center environments for nearly a decade. 10 Gigabit Ethernet (10GE) is a technology that has been used over the past eight years to provide higher capacity uplinks between switches.

High performance servers utilize SCSI hard drives that have a distance limitation of about 10 meters (32.8 feet). Fibre channel was designed to overcome the distance limitations of SCSI, while utilizing SCSI drives for storage by using SCSI as an upper layer protocol. Fibre channel (FC) host bus adapters (HBA) provide connectivity to the SAN through director class switches sold by EMC and other storage vendors. Fibre Channel HBAs operate at speeds of 1, 2, 4, and 8 Gbps, but 8Gbps FC HBAs are not widely adopted at the time of this writing.

FCoE converges the LAN NIC and SAN HBA functionality into one 10GE NIC card that provides an HBA and 10GE ASIC (application specific integrated circuit). Emulex and QLogic are the pioneers of this technology at the time of this post. The 10GE NICs are available as a single or dual port solution. The 10GE interfaces connect to FCoE interfaces on the Cisco Nexus 5000 switches, which will provide connectivity to both the LAN and the SAN, eliminating the need for FC director switches and HBAs saving real estate, power, and cost in the data center. Servers utilizing the PCI express 1.1 (8x or 16x) standard will support wire rate 10GE speeds.

Converging storage and network traffic onto the same infrastructure provides a unified I/O (input/output) fabric. The Nexus 5000 series switch provides 20 (5010) or 40 (5020) 10GE interfaces for data center network connectivity with the option of one (5010) or two (5020) expansion slots that allow the following connectivity options allowing enterprises to migrate to FCoE:

  • 8 port FC card (1/2/4 Gbps supported)
  • 4 port FC card / 4 port 10GE FCoE
  • 6 port 10GE FCoE

Author: Dennis Hartmann

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