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APPENDIX C — INITIALIZATION INFORMATION
The OM undergoes an automatic initialization process on power-up or reset, during
which it loads the executable software and parameter settings that control its
operation. The OM performs initialization either by self-booting from internal
non-volatile memory or externally booting from another device. External initialization
is performed by downloading information from a LAN connected BOOTP server.
Some initialization information can also be loaded externally from a device connected
to the OM front panel RS-232 interface (see
Appendix E, "RS-232 Test/Console Port"
Self-boot OM initialization enables the OM to operate:
•
Without connecting it to the headend LAN
•
In a headend LAN that does not include a BOOTP server
External OM initialization enables the OM to:
•
Modify the setup of an installed OM to accommodate system configuration
changes
•
Load upgraded executable software into an installed OM
Self-Boot Initialization
The OM begins initialization by determining the type of boot operation (BOOTP) and
by broadcasting BOOTP requests over its ENET1 Ethernet port. Self-boot
initialization occurs when the OM times out waiting for a reply and then initializes
itself from the information stored in its non-volatile memory.
External Initialization from a LAN Resident BOOTP Server
For external initialization to occur from a BOOTP server:
•
The OM must be connected to the system Ethernet LAN on
ENET1
•
A BOOTP or DHCP server must be present on the LAN
•
The BOOTP or DHCP server must have the OM MAC address
The OM begins initialization by broadcasting BOOTP requests over its ENET1
Ethernet port. The BOOTP server receives the OM BOOTP requests and provides a
BOOTP response packet containing the assigned IP addresses and bootfile entries,
from which the OM initializes. The response packet may also contain a gateway if
the BOOTP server is on a different network segment than the OM Ethernet
interface.
On receipt of the BOOTP reply, the OM obtains the FOF filename (OMv12.fof) and
path, which it downloads from the BOOTP server. The OM then parses the FOF and
compares the listed source files in the FOF with those maintained in the OM local
copy of the previously used version. If any listed source filename or path has
changed, or if there is a force download flag for any listed files (indicated by an “F”
at the end of the line listing the file), the listed file is then downloaded to the OM. If
