Siemens Unix V4.0 - Manual (Page 98)

Configuring Advanced Server for UNIX Configuring NetBIOS
Product Manual U7613-J-Z815-6-76
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5.1.1 Introduction to NetBIOS
An important part of Advanced Server for UNIX communication is not based directly on
TCP/IP protocols but uses NetBIOS.
In terms of the OSI Reference Model for a layered networking architecture, NetBIOS is a
level 5 protocol (“Session Layer”). The session layer establishes a communications session
between processes running on different computers. Functions of the session layer include:
● Name Service: The Name Service allows application processes to register unique
NetBIOS names. It provides the means by which these names can be resolved to the
network layer.
● Session Service: The Session Service is responsible for establishing, monitoring, and
terminating a virtual-circuit session between two processes identified by their NetBIOS
names.
● Datagram Service: This service allows application processes identified by their
NetBIOS names to exchange datagrams (messages of limited length).
On Advanced Server computers, NetBIOS services are provided by two STREAMS drivers
which are linked to the UNIX kernel during NetBIOS installation.
NetBIOS Names
The NetBIOS name space is flat (that is, it is not hierarchical), so all names within a network
must be unique. NetBIOS names are 16 characters in length. Advanced Server for UNIX
as well as Microsoft networking components allow the first 15 characters of a NetBIOS
name to be specified by the user or administrator (usually a given name is converted to
uppercase letters and padded with spaces), but reserve the 16th character of the NetBIOS
name to indicate a resource type (00-FF hex). Names can be registered as unique (one
owner) or as group (multiple owner) names. In addition to this there is also the concept of
an
internet group (with multiple owners and multiple addresses). Following are the important
NetBIOS names used in Advanced Server environments:
Unique names:
<computername>[0x00]
<computername>[0x03]
<computername>[0x20]
<username>[0x03]
<domain_name>[0x1D]
<domain_name>[0x1B] Workstation Service
Messenger Service
Server Service
Messenger Service
Master Browser
Domain Master Browser (PDC)