Communications security is enhanced through better IPsec integration throughout the various pieces of the TCP/IP stack. Hardware is used more efficiently and robustly to speed up performance of network transmissions, intelligent tuning and optimization algorithms run regularly to ensure efficient communication, and APIs to the network stack are more directly exposed, making it easier for developers to interact with the stack. Let's take a look at some of the improvements in what the team is calling the next-generation TCP/IP Stack.

TCP/IP stack enhancements

One improvement to the TCP/IP stack is the autotuning TCP window size: Longhorn Server can automatically tune the size of the receive window by each individual connection, increasing the efficiency of large data transfers between machines on the same network. Microsoft quotes the following example: "On a 10 Gigabit Ethernet network, packet size can be negotiated up to 6MB in size." I was unable to replicate this in my testing, but that may well be due to limitations in my equipment more than a faulty software implementation.

The dead gateway detection algorithm present in Windows Server 2003 has been slightly improved in the Beta 2 release. Windows now tries every so often to send TCP traffic through what it thinks to be a dead gateway. If the transmission doesn't error out, then Windows automatically changes the default gateway to the previously detected dead gateway, which is now live.

And Longhorn Server supports offloading network-processing functions from the CPU itself to the processing circuitry on the network interface card (NIC), freeing up the CPU to manage other processes.