HP Virtual Connect Flex-10 10Gb Ethernet Module for c-Class BladeSystem - Manual (Page 77)

Network management 77
Virtual Connect can only control link speed for Flex-10 NICs when they are connected to an HP Virtual
Connect Flex-10 Module. Virtual Connect cannot control the link speed of traditional NICs. For additional
information, see "Flex-10 overview (on page 100)."
MAC Cache Failover
When a VC-Enet uplink that was previously in standby mode becomes active, it can take several minutes
for external Ethernet switches 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 (5 seconds recommended) and completes in about 1 minute.
IMPORTANT: Be sure to set switches to allow MAC addresses to move from one port to
another without waiting for an expiration period or causing a lock out.
IGMP Snooping
The IGMP Snooping feature allows VC-Enet modules to monitor (snoop) the IGMP IP multicast membership
activities and configure hardware Layer 2 switching behavior of multicast traffic to optimize network
resource usage. Currently only IGMP v1 and v2 (RFC2236) are supported.
The IGMP Snooping idle timeout interval is set to 260 seconds by default. This value is the "Group
Membership Interval" value as specified by IGMP v2 specification (RFC2236). For optimum network
resource usage, set the interval to match the configuration on the customer network's multicast router
settings.