The networking and communications infrastructure is the most fundamental aspect of a network operating system. It provides connectivity and interoperability with client systems as well as other server-based operating systems. This infrastructure includes network architecture (physical device and media support), protocol support, networking services, Routing and Remote Access Services, and virtual private networking (VPN) services, Wide Area Network (WAN) connectivity, telephony, and Quality of Service (QoS). The best network operating system is that which offers the best balance of feature depth and ease of management in the above-mentioned areas.
Of the three network operating systems, the Windows 2000 Server network and communications infrastructure provides the most feature-complete and highly usable solution. Windows 2000 Server is highly available, as configuration changes are totally dynamic in most cases and do not require server downtime, and it is the only network operating system to offer a QoS implementation.
Windows NT Server 4.0 features telephony, and a VPN solution but does not, offer a QoS implementation. Manageability is entirely GUI-based but cannot compare with the ease-of-use, consistency, and additional capabilities featured in the Windows 2000 Server MMC, and configuration changes almost always require a server reboot.
Solaris 7 does not offer telephony solutions of any kind but does offer a strong VPN solution through SunScreen SKIP. Manageability is complex, as almost every aspect of configuration requires the use of a combination of command line tools and GUI-based tools. In general, availability is better than Windows NT Server 4.0, as fewer reboots are required for configuration changes.