System information

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AS/400 IBM Network Station: Techniques for Deployment in a WAN
Release 3 contains an option, TFTP subnet broadcast , that can significantly
decrease the amount of data transmitted during the boot process, as well as
saving significant CPU cycles in the AS/400 system. This option is described
in more detail in the following sections.
2.5.1.1 IBM Network Station Initialization
Initialization, at this time, is non-trivial and can be a performance concern for
some customers. The time required to initialize the Network Station,
particularly when many Network Stations are initialized simultaneously, can
be prohibitive. In addition, initialization can consume a lot of AS/400 CPU
useage, which may impact other jobs on the AS/400 system.
If possible, it is best to leave the Network Station powered-on after
initialization or to stagger initialization. The IBM Network Station consumes
very little power. If initialization times are a problem and power outages are a
concern, consider battery backups for each IBM Network Station, or server
systems dedicated to initialization.
2.5.1.2 Initialization Mechanisms
Initialization is performed using TCP/IP Trivial File Transfer Protocol (TFTP)
and AS/400 Remote File System (RFS). Both of these access methods read
files from the AS/400system to the Network Station. For reliability and
performance, both mechanisms subdivide files into blocks for sending, and
then recombine them in the Network Station. The TFTP block size can be
configured as 512 to 8192 bytes. The RFS block size is currently fixed at
8192. TFTP and RFS is used during initialization depending on the
configured initialization options.
There are three possible ways to initialize the Network Station:
•NVRAM
The AS/400 system and Network Station IP addresses and other
information are configured in each Network Station. The Network Station
sends a TFTP request to the configured server to begin initialization.
•BOOTP
The Network Station broadcasts to find a responding AS/400 server. The
AS/400 server is previously configured with the IP address and other
information for each Network Station . After the server receives a
broadcast from a Network Station, it begins the initialization.
•DHCP
The same as BOOTP except the AS/400 server contains a pool of Network
Station IP addresses. BOOTP or DHCP is the preferred method, for