System Administration Guide: Naming and Directory Services (NIS+)

NIS+ Over Wide Area Networks

Server-use customization is particularly valuable for large networks with many subnets and networks that span multiple geographic sites connected by modems or leased lines. To maximize network performance, you want to minimize network traffic between subnets, and between sites linked by slower connections. You can do that by specifying which NIS+ servers the clients can use, and their order of server preference. In this way you confine as much NIS+ network traffic as possible to the local subnet.