H3C SR6608/6604 Routers Installation Manual
Chapter 7 Maintaining Software
7-13
Table 7-6
Device control sub-menu
Menu item
Description
<1> Display All Available Nonvolatile
Storage Device(s)
Display all available storage device(s).
<2> Set The Operating Device
Configure the operating device.
<3> Set The Default Boot Device
Configure the default boot device.
<0> Exit To Main Menu
Return to the main menu.
7.3 Updating BootWare and Applications Through a Serial
Interface
7.3.1 Introduction to Xmodem
Use Xmodem when updating BootWare and an application through a serial interface.
Xmodem is a file transfer protocol that is widely used due to its simplicity and high
performance. Xmodem transfers files through a serial interface. It supports two types of
data packets (128 bytes and 1 KB), two check methods (checksum and CRC), and
error packet retransmission mechanism (generally the maximum number of
retransmission attempts is 10).
The Xmodem transmission procedure is completed by the cooperation of a receiving
program and a sending program. The receiving program sends a negotiation character
to negotiate a packet check method. After the negotiation, the sending program starts
to transmit data packets. When receiving a complete packet, the receiving program
checks the packet using the agreed method.
z
If the check succeeds, the receiving program sends an acknowledgement
character and the sending program proceeds to send another packet.
z
If the check fails, the receiving program sends a negative acknowledgement
character and then the sending program retransmits the packet.
7.3.2 Modifying Serial Interface Parameters
In actual applications, you need to make the serial interface baud rate higher to save
updating time or make it lower to guarantee transmission reliability. This section
introduces how to adjust the serial interface baud rate.
Enter the main menu and select
2
to enter the serial interface sub-menu, and then
select
5
on the sub-menu to modify the baud rate. The system displays the following:
============================<BAUDRATE SET>============================
|Note:'*'indicates the current baudrate |
| Change The HyperTerminal's Baudrate Accordingly |
| Press 'Enter' to exit with things untouched. |
