NetBIOS

NetBIOS, which stands for Network Basic Input/Output System, is a session-layer interface used by applications to communicate. Its logical naming system permits computers' network interfaces to establish connections, and ensures reliable data transfer between computers once the connections exist.

Lana Numbers

LAN Adapter (Lana) numbers are part of the logical naming system established by NetBIOS. SunLink Server software assigns Lana numbers automatically to each network interface, choosing a number that is unique within the particular computer.

One NetBIOS Lana can be configured for each available network interface card. You should plan ahead to choose the particular network interfaces that you want to run NetBIOS Lanas.

WINS Servers

A Windows Internet Name Service (WINS) server is a machine that maintains a database of available network resources and the computers that own them. A computer seeking such a resource "asks" the WINS server to look up the address of the machine that owns the resource.

A network can have no WINS servers, or it can have any number of them. See a fuller discussion of WINS in Chapter 5, Chapter 5, Implementing WINS and Maintaining Databases.

WINS and NetBIOS Modes

By default, SunLink Server software brings up each network interface in Broadcast mode. In this mode, a computer seeking a network service or resource broadcasts a general request to the network, seeking a response from the machine that owns the resource or service. Each computer receiving such a request responds with its address.

This mode has the advantage of not requiring WINS servers, but it generates a lot of network traffic. Broadcast mode does not work across subnets.

WINS servers use the NetBIOS Hybrid mode (h-mode). In this mode, a computer seeking a network service or resource sends that request directly to a specified WINS server, which in turn looks up the address of the machine that owns the resource.

WINS Proxy

WINS proxies are useful in networks comprising several subnets, where some of the computers on those subnets are running in Broadcast mode. A WINS proxy fields local requests for services located on a different subnet, caching network addresses and communicating with the WINS server when necessary.

You can also configure the NetBIOS service to use WINS servers to resolve NetBIOS names by entering the IP address of the primary and secondary WINS servers. You can configure only the primary WINS server, or both. The WINS server addresses can be the IP address of the local SunLink Server system running the WINS service, or another SunLink Server system running the WINS service, or a Windows NT server running the WINS service.

If either primary or secondary WINS servers are configured, you can use the WINS proxy setting to allow this SunLink Server system to provide WINS proxy service to other computers that have not been configured to use WINS servers to resolve NetBIOS names. Be discreet in using this option, as it joins the NetBIOS name spaces for both b-mode and h-mode NetBIOS nodes on the local subnet, and can cause unexpected name conflicts.

NetBIOS Scope

NetBIOS scope is a seldom-used feature that limits the computers that a particular network device can communicate with.

The chief use of scope is in wide area networks (WANs) or other large networks, where it can prevent conflicts caused by two or more network interfaces having the same NetBIOS name.

Consider a network belonging to a shoe manufacturer where two machines, both earmarked for use by Sales personnel, exist on the same subnet.

One machine is used by those selling sneakers, and the other by those selling boots. If both machines had the NetBIOS name "sales," problems would result. However, if one machine is given the scope name "sneakers" and the other "boots," then both machines could retain the NetBIOS name "sales" without any conflict. Note however, that both machines could then only communicate with other machines possessing the same scope.