User's Manual

Virtual Connect networks 99
Gb for Ethernet connections. The 20Gb maximum speed is dependent on 20Gb NICs and the HP VC
FlexFabric-20/40 F8 Module being present in the domain. The pre-4.01 behavior can be retained by setting
"maximum speed" to the same value as "preferred speed". When the maximum speed and preferred speed
for a network are set to the same bandwidth, then the profile connection bandwidth does not exceed the
custom speed set on the connection.
IMPORTANT: Depending on the NIC firmware versions in use, you might need to upgrade the
NIC firmware for these speed enforcement settings to work correctly.
To change these settings:
1. Click the selection box, and then select a setting (100Mb to 20Gb):
o Set preferred connection speed. This value is the default speed for server profile connections
mapped to this network. The server administrator can increase or decrease this setting on an
individual profile connection. This setting is used for the minimum bandwidth.
o Set maximum connection speed. This value is the maximum speed for server profile connections
mapped to this network. This setting limits the maximum port speed from the server to the network
connection associated with the multiple networks. Maximum bandwidth is determined by the
maximum connection speed of the network. All multiple networks share the same maximum
connection speed.
The availability of the 20Gb setting is dependent on 20Gb NICs and HP VC FlexFabric-20/40 F8
Modules being present in the domain.
2. Click Apply.
Virtual Connect can control link speed for FlexNICs only when they are connected to an HP Virtual Connect
Enet Module. Virtual Connect cannot control the link speed of traditional NICs.
IMPORTANT: Each FlexNIC and FlexHBA is recognized by the server as a PCIe physical function
device with adjustable speeds from 100 Mb to 10 Gb in 100 Mb increments when connected to
an NC553i/m 10Gb 2-port FlexFabric FlexFabric Adapter or any Flex-10 NIC. For NC551i/m
Dual Port FlexFabric 20 Gb FlexFabric Adapters, the range is limited to 1 Gb to 20 Gb in 100 Mb
increments.
MAC Cache Failover
When a VC-Enet uplink that was previously in standby mode becomes active, external Ethernet switches can
take several minutes to recognize that the c-Class server blades can now be reached on this newly active
connection. Enabling Fast MAC Cache Failover causes Virtual Connect to transmit Ethernet packets on newly
active links, which enables the external Ethernet switches to identify the new connection and update their
MAC caches appropriately. This transmission sequence repeats a few times at the MAC refresh interval (HP
recommends 5 seconds) and completes in about 1 minute.
Virtual Connect only transmits MAC Cache update frames on VLANs that have been configured in the VC
domain. The update frames are VLAN tagged appropriately for networks defined on shared uplink sets. For
dedicated networks, only untagged update frames are generated, regardless of whether or not VLAN
Tunneling is enabled. In a VLAN tunnel, all customer VLAN tags pass through Virtual Connect transparently.
Virtual Connect does not examine nor record VLAN tag information in tunneled networks; therefore, it cannot
generate tagged update frames.