Fabric Manager Users Guide, Version 6.1, Revision A - QLogic

3–Fabric Manager Configuration
Configuring the QLogic Fabric Manager
Table 3-6. Sm Fat Tree Topology Parameters
Parameter
Default
Value
Description
TierCount 3 The number of tiers in the fat tree
CAsOnSameTier 1 Discovery algorithm a bit more streamlined
if CAs on same tier, but this is not a
requirement.
NodeDesc
When Systematic routing algorithm is in
use, nodes may be specified for exclusion
from initial round-robin to give better
route balancing of remaining nodes. This
may be useful in asymmetric fat trees or
to initially balance across compute nodes
in the tree.
IB Multicast
InfiniBand Trade Association (IBTA) has a limitation in that the SM must make the
realizable decision for a Multicast group at Multicast Join/Create time. However
later fabric changes (removal of links, loss of switches) could make the multicast
group unrealizable, but there is no notice in IBTA which the SM could send the
end node.
To address this situation, the SM performs stricter Multicast checking at
Join/Create time. This means a Multicast join/create is rejected if there are any
switch to switch links which do not have at least the MTU or Rate requested for
the Multicast group. The rejection reduces the chance that a simple fabric failure
could make the group unrealizable.
The parameters in Table 3-7 control Fabric Multicast Routing. These are all part of
the Multicast subsection within the Sm section.
Table 3-7. Sm Multicast Routing Parameters
Parameter
Default
Value
Description
DisableStrictCheck 0 When 1, disables the strict checking and
accepts Join/Create for which at least 1
viable fabric path exists.
MLIDTableCap 1024 Number of Multicast LIDs available in fabric.
Must be set to less than or equal to
the smallest Multicast forwarding table
size of all switches in fabric.
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