If your symmetric multiprocessing (SMP) system supports network affinity migration, each SQL Server engine handles the network I/O for its connections in release 11.0. During login, SQL Server migrates the client connection task from engine 0 to the engine that is servicing the smallest number of connections. The client’s tasks run network I/O on that engine until the connection is terminated.
By distributing the network I/O among its engines, SQL Server can handle more user connections. The per-process limit on the maximum number of open file descriptors no longer limits the number of connections. Adding more engines linearly increases the maximum number of file descriptors. For more information about how multiple network engines work in an SMP environment, see Chapter 10, “Managing Multiprocessor Servers,” in the System Administration Guide.
