Load Balancing and Failover

Note NDIS 5. x has been deprecated and is superseded by NDIS 6. x. For new NDIS driver development, see Network Drivers Starting with Windows Vista. For information about porting NDIS 5. x drivers to NDIS 6. x, see Porting NDIS 5.x Drivers to NDIS 6.0.

Load balancing and failover (LBFO) functionality can improve the reliability and performance of a miniport driver's network adapters. A miniport driver can use LBFO to balance its workload by distributing the workload over the miniport driver's bundle of adapters. That is, the miniport driver can use LBFO to offload tasks from the primary adapter to any secondary adapter. For example, suppose a protocol driver requests a miniport driver to transmit packets. To balance packet-transmission workload, that miniport driver can use its primary adapter to transmit some of those packets and can offload some of those packet transmissions to secondary adapters. LBFO functionality also makes it possible for a miniport driver to set one of the secondary adapters to take over packet transfers and information requests if the primary adapter fails.

The following topics describe LBFO and how to implement miniport drivers to support LBFO:

About LBFO

Specifying Support of LBFO

Implementing LBFO in a Miniport Driver

For information about adding LBFO functionality to a miniport driver, see the readme for the Passthru driver. This miniport driver is a sample intermediate miniport driver included in the Microsoft Windows Driver Kit (WDK).

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