H3C Technologies H3C S9500 Series Switches - Manual (Page 123)

Installation Manual
H3C S9500 Series Routing Switches
Chapter 6 Switch Monitoring and Maintenance
6-14
Figure 6-9 Attribute settings of HyperTerminal serial interface
II. Upgrading software through console port (XModem)
1) Brief introduction to XModem
XModem, a type of file transfer protocol, is broadly applied for its simplicity and good
performance. It transmits files through serial interfaces, supporting 128 bytes and
1Kbytes in terms of data unit, checksum and CRC in terms of checking mode, and
multiple retransmissions (usually ten attempts) in the event that packet errors are
found.
XModem completes transmission by the receiving program (receiver) and the sending
program (sender). In XModem, the transmission begins with the sending of negotiation
characters from the receiver for the purpose of check mode negotiation. After passing
the negotiation, the sender is allowed to send the first data packet. Upon the receipt of
the complete packet, the receiver checks the packet using the agreed checking mode
and will send an ACK if the packet has passed the check and a NAK if not. Receiving
the ACK, the sender will send the next packet; receiving the NAK instead, the sender
will retransmit the previously sent packet.
2) Xmodem application
Step 1: In the Boot menu, enter 4, press , and the system will access the serial
interface submenu: