Cyclic Redundancy Check On Downloaded Configuration Files; Automatic Update Configuration Examples - AudioCodes Mediant 4000 SBC User Manual

CHAPTER 40 Automatic Provisioning
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Cyclic Redundancy Check on Downloaded Configuration Files

You can enable the device to perform cyclic redundancy checks (CRC) on downloaded
configuration files during the Automatic Update process. The CRC checks whether the content
(raw data) of the downloaded file is different to the content of the previously downloaded file from
the previous Automatic Update process. The device compares the CRC check value (code) result
with the check value of the previously downloaded file. If the check values are identical, it indicates
that the file has no new configuration settings, and the device discards the file. If the check values
are different, it indicates that the downloaded file is different (i.e., includes updates), and the device
installs the downloaded file and applies the new configuration settings.
CRC is useful, for example, when the service provider replaces a file, on the provisioning server,
with another file whose contents are the same. When the device sends an HTTP Get request
during the Automatic Update process, the provisioning server sends the new file to the device. This
occurs as the timestamp between the previously downloaded file and this new file is different
(determined by the HTTP If-Modified-Since header in the Get request). Therefore, the CRC feature
can be used to prevent the device from installing such files.
For enabling CRC, use the ini file parameter AUPDCheckIfIniChanged or CLI command, configure
system > automatic-update > crc-check regular. By default, CRC is disabled. For more information
on the parameter, see

Automatic Update Configuration Examples

This section provides a few examples on configuring the Automatic Update feature.
For ini file downloads, by default, parameters not included in the file are set to
defaults. To retain the current settings of these parameters, set the
SetDefaultOnINIFileProcess parameter to 0.
The CLI Startup Script file is not supported when the device operates in HA mode.
If you have configured one-time software file (.cmp) download (configured by the
[CmpFileURL] parameter or CLI command configure system >
automatic-update > firmware), the device will only apply the file if one-time
software updates are enabled. This is disabled by default to prevent unintentional
software upgrades. To enable one-time software upgrades, set the
[AutoUpdateCmpFile] parameter to [1] or CLI command, configure system >
automatic-update > update-firmware on.
If you need to update the device's software and configuration, it is recommended to
first update the software. This is because the current ("old") software (before the
upgrade) may not be compatible with the new configuration. However, if both files
are available for download on the provisioning server(s), the device first downloads
and applies the new configuration, and only then does it download and install the
new software. Therefore, this is a very important issue to take into consideration.
If more than one file needs to be updated:
✔
CLI Script and cmp: The device downloads and applies the CLI Script file on
the currently ("old") installed software version. It then downloads and installs
the cmp file with a reset. Therefore, the CLI Script file MUST have
configuration compatible with the "old" software version.
✔
CLI Startup Script and cmp: The device downloads both files, resets, applies
the new cmp, and then applies the configuration from the Startup Script file on
the new software version.
✔
CLI Script and Startup Script: The device downloads and applies both files; but
the Startup Script file overwrites all the configuration of the CLI Script file
Automatic Update Parameters.
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Mediant 4000 SBC | User's Manual