NetApp and VMware vSphere Storage Best Practices

Figure 29) Configuring flow control settings.
9.4 SPANNING TREE PROTOCOL
The Spanning Tree Protocol (STP) is a network protocol that makes sure of a loop-free topology for any
bridged LAN. In the OSI model for computer networking, STP falls under the OSI layer-2. STP allows a
network design to include spare (redundant) links to provide automatic backup paths if an active link fails,
without the danger of bridge loops, or the need for manual enabling/disabling of these backup links. Bridge
loops must be avoided because they result in flooding the network.
When connecting ESX and NetApp storage arrays to Ethernet storage networks it is highly recommended
that the Ethernet ports that these systems connect to be configured with either RSTP or portfast enabled.
9.5 BRIDGE PROTOCOL DATA UNITS
Bridge Protocol Data Units (BPDUs) exchange information about bridge IDs and root path costs within STP.
When connecting ESX and NetApp storage arrays to Ethernet storage networks it is highly recommended
that the Ethernet ports which these systems connect to are configured with BPDU disabled.
9.6 NETAPP VIRTUAL INTERFACES
A virtual network interface (VIF) is a mechanism that supports aggregation of network interfaces into one
logical interface unit. Once created, a VIF is indistinguishable from a physical network interface. VIFs are
used to provide fault tolerance of the network connection and in some cases higher throughput to the
storage device.
NetApp enables the use of two types of load-balancing VIFs: Multimode and Dynamic Multimode.
Multimode VIFs are static configured Ethernet trunks. In a multimode VIF, all of the physical connections in
the VIF are simultaneously active and can carry traffic. This mode requires that all of the interfaces be
connected to a switch that supports trunking or aggregation over multiple port connections. The switch must
be configured to understand that all the port connections share a common MAC address and are part of a
single logical interface. In the event of a physical interface failure resulting in the loss of link the VIF will
automatically transmit traffic on the surviving links in the VIF without loss of connectivity.
47