Users Guide

11–QLogic Teaming Services
Executive Summary
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The Link Aggregation control function determines which links may be aggregated
and then binds the ports to an Aggregator function in the system and monitors
conditions to determine if a change in the aggregation group is required. Link
aggregation combines the individual capacity of multiple links to form a high
performance virtual link. The failure or replacement of a link in an LACP trunk will
not cause loss of connectivity. The traffic will simply be failed over to the remaining
links in the trunk.
SLB (Auto-Fallback Disable)
This type of team is identical to the Smart Load Balance and Failover type of
team, with the following exception—when the standby member is active, if a
primary member comes back on line, the team continues using the standby
member rather than switching back to the primary member. This type of team is
supported only for situations in which the network cable is disconnected and
reconnected to the network adapter. It is not supported for situations in which the
adapter is removed/installed through Device Manager or Hot-Plug PCI.
If any primary adapter assigned to a team is disabled, the team functions as a
Smart Load Balancing and Failover type of team in which auto-fallback occurs.
Software Components
Teaming is implemented through an NDIS intermediate driver in the Windows
operating system environment. This software component works with the miniport
driver, the NDIS layer, and the protocol stack to enable the teaming architecture
(see Figure 11-2 on page 140). The miniport driver controls the host LAN
controller directly to enable functions such as sends, receives, and interrupt
processing. The intermediate driver fits between the miniport driver and the
protocol layer multiplexing several miniport driver instances, and creating a virtual
adapter that looks like a single adapter to the NDIS layer. NDIS provides a set of
library functions to enable the communications between either miniport drivers or
intermediate drivers and the protocol stack. The protocol stack implements IP,
IPX, and ARP. A protocol address such as an IP address is assigned to each
miniport device instance, but when an Intermediate driver is installed, the protocol
address is assigned to the virtual team adapter and not to the individual miniport
devices that make up the team.
The QLogic-supplied teaming support is provided by three individual software
components that work together and are supported as a package. When one
component is upgraded, all the other components must be upgraded to the
supported versions.