Receive-side scaling is especially important in multi-core and multi-processor systems because of the architecture of the NDIS 5.1 miniport drivers. Without the SNP and Receive-side Scaling, multi-processor and multi-core Windows 2003 Server systems route all incoming network traffic interrupts to exactly one processor core, resulting in limited scalability, regardless of the number of processors or processor cores in the system. With SNP and Receive-side Scaling and the NDIS 5.2 miniport driver, incoming network traffic interrupts are distributed among the processors and processor cores on the computer. Receive-side Scaling-capable network adapters are now available, and are required to take advantage of this feature. Support for this feature is currently found in some, but not all server-class network adapters.
The Scalable Networking Pack monitors network adapters for Receive-side Scaling capabilities. If a network adapter supports Receive-side Scaling, the Scalable Networking Pack uses this capability across all TCP connections, including connections that are offloaded through TCP Offload.