HP Mellanox SX1018 Converged Networks and Fibre Channel over Ethernet - Page 4

In a single-hop FCoE/DCB network architecture, a function within a switch known as a Fibre Channel Forwarder (FCF) passes encapsulated Fibre Channel frames between a servers' CNA and the Fibre Channel storage area networks (SAN) where the Fibre Channel storage targets are connected. An FCF is typically an Ethernet switch with DCB, legacy Ethernet, and legacy Fibre Channel ports. Examples of FCFs include HP VC FlexFabric modules and HP Networking 5820X top-ofrack access switches with Fibre Channel option modules. FCoE has several advantages: • The CNA appears to the OS as a FC HBA and a NIC and uses existing OS device drivers. FCoE is implemented internal to the CNA and its device driver, but the fact that FCoE is in use is not presented to the server OS. • Uses the existing Fibre Channel security and management model • Makes storage targets that are provisioned and managed on a native Fibre Channel SAN transparently accessible through an FCoE FCF However, there are also some challenges with FCoE: • For anything other than a single-hop scenario (CNA to first switch where storage traffic is broken out to native Fibre Channel uplinks), it must be deployed on a DCB-enabled Ethernet network, as a lossless transport is needed. • Requires CNAs and new DCB-enabled Ethernet switches between the servers and FCFs (to accommodate DCB) • Is a non-routable over-IP protocol primarily used within the data center, as are native Fibre Channel protocols today • Requires an FCF device to connect the DCB network to the legacy Fibre Channel SANs and storage • Requires validating a new fabric infrastructure that converges LAN communications and Fibre Channel traffic over DCB-enabled Ethernet. Validating the network ensures that you have applied proper traffic class parameters to meet your IT organizations' business objectives and service level agreements. The first step of server converged I/O at the server edge (network's first hop) is available now. Organizations achieve significant equipment cost savings by reducing the number of interfaces required for each server and the number of interconnects providing that first hop. Extending converged network as an end-to-end implementation in multi-hop networks holds a different set of challenges. Challenges for end-to-end network convergence This section describes challenges to network convergence that arise both from the varied demands placed on network infrastructure in enterprise environments, and from established network technologies that offer alternatives to FCoE Many people within the IT community expect FCoE to allow end-to-end use of Ethernet for storage as well as traditional IP network traffic. The networking community expects FCoE to be an open, interoperable protocol where FCoE and TCP traffic co-exist on multivendor Layer 2 networks. The storage community expects everything currently running on Fibre Channel to operate over Ethernet. They also expect to include the installed base of Fibre Channel hardware in that network for its useful lifetime. CFOs expect to reduce maintenance costs by ultimately merging the physical Fibre Channel and Ethernet infrastructure. Vendors are currently implementing DCB standards in network hardware and firmware. HP Virtual Connect FlexFabric technology has provided standards-based converged networking to the server edge since 2010. Realistically, however, FCoE can't be all things to all parties, at least not at the same time. Cisco is one of the few vendors promoting end-to-end FCoE networks that utilize more than a single switch (that is, multiple FCoE/DCB switch hops from servers to storage). The vendor-centric path Cisco has chosen sacrifices Layer 2 interoperability and possible cost reduction for users in a heterogeneous hardware environment. Instead, Cisco chooses to extend its Fibre Channel switch functionality and protocols from its native Fibre Channel switch products to burden its Ethernet products with the same limitations and lack of interoperability. Fibre Channel networks are inherently single vendor. Therefore, prolonging interoperability with existing Cisco Fibre Channel hardware results in vendor lock-in for every switch in the data center. This is not consistent with customer expectations described in the beginning of this section. Servers Enterprise data centers typically pool (share) storage for access over Fibre Channel. For high availability, a server typically has two or more LAN connections and two Fibre Channel connections to provide redundancy. It may have even 4