Appendix D - Network Migration D-1
A
PPENDIX
NETWORK MIGRATION

Upgrading CDM-570/CDD-564 Series Modems to Firmware Version 1.5.3

General
This document covers the migration of networks with CDM-570 and CDD-564
series modems to Firmware version 1.5.3 from any earlier versions of code. It
addresses the issues customers will face when migrating their networks and
provides a step-by-step plan to facilitate the process.
Comtech Vipersat Networks strives to make firmware migrations as painless as
possible by maintaining backward compatibility with prior versions of code.
Only under unavoidable circumstances where it is absolutely necessary will
backward compatibility be broken. To provide a considerable increase in perfor-
mance and reliability, the HDLC over-the-air frame was changed from 16 to 24
bit Cyclic Redundancy Check (CRC). By doing so, backward compatibility
with all previous versions has been broken.
Customers with existing networks will need to carefully plan the migration to
the new version of code. There is no particular problem presented for upgrading
Hub units, Remote mesh units or spares inventories. However, as soon as the
Hub units are rebooted to the new v1.5.3 code they will lose communications
with Remote data units that are running v1.5.2.2 or earlier code. The Hub oper-
ator must take care to insure all Remote data units that are online have the new
v1.5.3 code in the slot to which they will reboot.
Note that the main concern is for any Remotes that are offline during the migra-
tion phase, and then come back online sometime afterwards.