Showing posts from March, 2015

Cisco Data Center: Unified Fabric and FCoE

TIP: In FCoE world there are no HBAs, but there are CNAs instead. All the Storage concepts stay the same. TIP: If you want to use the FCoE, you first need to enable the feature using the command “feature fcoe”. Also, have in mind that Max Length of the FCoE is 2240 bytes, and Jumbo Frames are required.
FCoE is a great model because it uses the Ethernet, and therefore enables the convergence of SAN and LAN (Unified Fabric). FCoE is an encapsulation of the FC frames into Ethernet. The only difference between FC and FCoE is the L1 and L2 TRANSPORT.
In the simplest FCoE topology, a server with CNA (converged network adapter; a card that can send both Ethernet and FCoE traffic over the same gigabit Ethernet uplink) is connected to an FCoE-enabled switch, which has a direct connection into the legacy FC network. The idea is to make Ethernet lossless, because Storage requires the lossless flow. FCoE is fully defined in FC-BB-5 standard, and it is defined by the following 3 criteria: -PFC (Loss…