HP Virtual Connect for c-Class BladeSystem Version 4.01 User Guide

Virtual Connect networks 112
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.
By default, unregistered IGMP multicast traffic traversing VC-Enet modules is flooded on the configured
Ethernet network. To prevent flooding, select the Prevent flooding of unregistered multicast traffic option.
Unregistered multicast traffic from uplinks is dropped and traffic from the server ports is redirected to the
active uplink port. IGMP Snooping must be enabled to modify this setting.
Multicast Filtering
A multicast filter is a set of rules for filtering the IGMP Reports. The server administrator defines the rules that
filter the IGMP report by specifying the multicast group IP address and the multicast group IP prefix length.
This defined filter can then be associated with a profile Ethernet connection. A multicast filter can contain up
to a maximum of 32 filter rules. A multicast filter without any rules is defined as an empty filter. One or more
multicast filters can be grouped into a multicast filter set. The multicast dataflow through the VC domain is
determined by the IGMP settings. Users can create a max of 400 filters in a domain.
A multicast filter or multicast filter set can be assigned to one or more profile Enet connections. A filter
configuration associated with a profile Enet connection applies to all vNets the server port is part of. Multicast
filters and filter sets can be defined and assigned to profile connections anytime after the VC domain is
configured. However, IGMP snooping MUST be enabled for filtering to be in effect. HP recommends
enabling the option to prevent flooding of unregistered multicast traffic when using filtering.
The following behavior can be expected when filters are configured in a VC domain:
• If one or more non-empty filters or filter sets are assigned to a profile Enet connection, an IGMP
Report/Leave message received from the server port is matched with the set of configured filter
rules. Reports matching the rules are allowed to join the group. Any non-matching Report is ignored.
• If no filters or filter sets are assigned to a profile Enet connection, all IGMP Reports received from the
respective server port are snooped by VC.
• If an empty filter or empty filter set is assigned to a profile Enet connection, no IGMP Report received
from the respective server port is snooped.
• If a filter rule is deleted from a multicast filter in use by a profile connection, it can take several seconds
(up to the idle timeout setting) for the server port to be removed from the IGMP group table.
With only IGMP Snooping enabled:
• Multicast traffic for registered groups is forwarded to all member ports.
• Unregistered multicast traffic is flooded to all VC ports.
• Multicast traffic targeted to link-local addresses (224.0.0.0 – 224.0.0.255) is flooded to all VC ports
in the configured network.
• Any other L2 multicast traffic is forwarded to all VC ports in the network.
With the "No Flood" feature enabled (IGMP snooping must be enabled to use this feature):
• Multicast traffic for registered groups is forwarded to all member ports.
• Unregistered multicast traffic from server downlink ports is forwarded to the active uplink port
configured for the corresponding Ethernet network.
• Multicast traffic targeted to link-local addresses (224.0.0.0 – 224.0.0.255) is flooded to all VC ports
in the configured network.