Alpha Technologies XP-EDH4 - Technical Manual - Manual (Page 75)

75 745-419-B0-001 Rev. A (11/2013)
4.0 Dual IP Configuration
4.1 Dual IP Applications
Occasionally you may want to access both the HMS side and the DOCSIS side of the transponder using
two separate IP addresses. The following sections provide the user with the information necessary for
configuring the transponder for use in a Dual IP Configuration. Transponders are shipped from the factory
configured for Single IP use. The operator must configure the transponder for the appropriate device type
prior to installing the transponder and prior to implementing the information presented in this manual.
Please refer to Section 3.8.2, Web Page Access, for information on configuring the transponder’s device
type via the Web interface.
4.2 Configuration File Choices
HMS configuration file data can be added to an existing cable modem configuration file or it can be
created in a separate HMS initialization file (typically named hmsinit.ini). Regardless of the file being
used, the file must reside on the TFTP (provisioning) server.
The decision of where to place the configuration data is based on considerations of access, maintenance
and security, as applicable to your specific enterprise.
The cable modem configuration file typically contains community strings and trap destination settings
via the docsDevNmAccessTable MIB OIDs. These settings allow restricted (SNMP-based) access to the
cable modem (DOCSIS) side of the transponder. If no other HMS configuration is specified, these settings
will also be used to control SNMP access to the HMS side of the transponder (Both IP addresses will
share the same access controls). It is also possible to add HMS configuration data to the cable modem
configuration file via a set of MIB OIDs (hmsInitMIBObjects) designed specifically for this purpose. Adding
these OIDs to the cable modem configuration file allows a separate (from docsDevNmAccessTable) set of
community strings and trap destinations unique to the HMS side of the transponder.
If a unique set of HMS community strings and trap destinations is desired for the HMS IP address, and it
is not convenient to add this information to the cable modem configuration file, it is also possible to create
a separate HMS initialization file that contains community strings and trap destinations to control access
to the HMS side of the transponder. This file must reside on the TFTP server specified in the DHCP offer
for the HMS side IP address.
The HMS transponder is designed to look for HMS configuration data in the cable modem configuration
file first. Any HMS configuration data added to the cable modem configuration file, even if it is incomplete,
causes the transponder to use the cable modem configuration file data and ignore the HMS initialization
file. This is important when deciding how to manage HMS devices. A clear decision must be made to
place configuration data in either one file or the other, with absolutely no redundancy.
Configuration data must reside in either the cable modem configuration file or the HMS initialization file, never
both.
IMPORTANT!
If HMS data is not present in the modem configuration file, the transponder will attempt to retrieve the
file whose name is specified in the bootfile name field of the DHCP offer (please refer to the Assigning
an IP Address to the Transponder section in this manual for details). If the bootfile name field is empty,
the transponder will attempt to retrieve a file with the name hmsinit.ini. If the attempt to retrieve the
hmsinit.ini file is unsuccessful, the transponder will reference the values specified in the
docsDevNmAccessTable located in the cable modem configuration file. If no entries are present in the
docsDevNmAccessTable, the transponder will allow open access to the HMS side of the transponder and
no traps will be generated.