HP-UX SNAplus2 R7 Administration Guide

Introduction to SNAplus2

SNAplus2 Components

Note

If the LAN is split by a network failure into two noncommunicating domains, each contain-

ing one or more backup servers, SNAplus2 cannot maintain a consistent conﬁguration of

domain resources across the LAN. In this situation, each domain has an acting master server,

each tracking changes made to the domain conﬁguration ﬁle in its own domain but unaware

of any changes made in the other domain. When the LAN connection is re-established, the

domain conﬁguration ﬁle from the original master server becomes the domain conﬁguration

ﬁle across the LAN, and any domain resource ﬁles on other servers are overwritten. (If the

master is inactive at this point, the domain conﬁguration ﬁle from the highest backup server

available in either of the two domains is used.) Because changes to a domain conﬁguration

ﬁle are not necessarily preserved when the connection is re-established, do not make any

changes to the ﬁle in either domain while the LAN connection is broken. Changes can still

be made to the conﬁguration of individual nodes.

SNAplus2 stores information about the master server and backup servers in the binary ﬁle sna.net, known as

the SNA network data ﬁle. The master copy of this ﬁle is stored on the master server; any changes made to it

are automatically copied to all other servers in the same way that changes to the domain conﬁguration ﬁle are

copied to backup servers. You cannot edit the contents of the SNA network data ﬁle directly; instead, SNAplus2

provides administration facilities (see Section 3.1,

Overview of SNAplus2 Administration) to access the ﬁle. (You

can edit node conﬁguration ﬁles directly when SNAplus2 is not running; but in general you should use SNAplus2

administration facilities to ensure that all conﬁguration information is valid and internally consistent.)

For more information about the SNA network data ﬁle, refer to HP-UX SNAplus2 Administration Command

Reference.

HP-UX Clients

UNIX

A client computer does not contain a conﬁguration ﬁle or SNA network data ﬁle. Instead, the client has a client

network data ﬁle that holds the information it needs to access servers on the SNAplus2 LAN. The client relies on

a server to provide the necessary conﬁguration information.

Most of the details of using HP-UX client computers are the same as those for a server, except that the client has

no node resources to deﬁne and manage. The following references provide more details about using a client:

• To start and stop the SNAplus2 software, see Chapter 3, Administering SNAplus2.

• To set up information required to support invokable TPs on the client, see Section 7.4, Deﬁning TPs.

• To manage the SNA network information required to access servers on the SNAplus2 LAN, see Chapter 11,

Managing SNAplus2 Client/Server Systems or refer to HP-UX SNAplus2 Administration Command Reference.

• To manage diagnostics information (logging and tracing), see Section 3.1.2, Administration Tools, or for more

detailed information, refer to HP-UX SNAplus2 Diagnostics Guide.

Windows Clients

WINDOWS

SNAplus2 enables machines running Microsoft Microsoft Windows 2000, Windows XP, Windows Server 2003,

Windows 3.1, Windows for Workgroups 3.11, or OS/2 to act as clients in the SNAplus2 domain.

You can run either a 16-bit version of the SNAplus2 client software (referred to in this guide as “Win16”)ora

32-bit version (referred to in this guide as “Win32”):

• The 16-bit version can be installed on machines running Windows 3.1 or Windows for Workgroups 3.11, or on

Win16 subsystems on Windows NT, Windows 95, or OS/2. SNA network information, and other conﬁguration

information required by Win16 clients, is held in the sna.ini ﬁle.