3Com Router 3000 Ethernet FamilyConfiguration Guide Chapter 5 File Management3Com Corporation5-16Note:You may specify a source IP address for the packets sent by the FTP server with thetftp source-interface command or with the tftp source-ip command. If bothcommands are configured, the one configured later overrides the former.5.4.3 Displaying and Debugging TFTPAfter completing the above configurations, execute the display command in any viewto verify them.Table 5-20 Display and debug TFTPOperation CommandDisplay the current source IP address ofthe TFTP client display tftp source-ip5.5 Xmodem ConfigurationXmodem is a file transfer protocol widely adopted for its simplicity and goodperformance.Xmodem transfers files through serial interfaces. It supports:z Two data packet sizes: 128 bytes and 1 KBz Two check methods: generic checksum and cyclic redundancy check (CRC)z Retransmission when error occurs (normally, 10 times)Xmodem comprises receiver and sending programs. The following is how it operates:1) The receiver sends a negotiation character to negotiate check method.2) After the negotiation is passed, the sender starts sending packets.3) When a complete data packet is received, the receiver checks it with theagreed-upon check method. If the check is passed, it sends an ACK asking thesender to send the next packet. If the check fails, it sends a NAK asking the senderto retransmit the packet.V 2.41 implements the receiving program of Xmodem. It is used on the AUX port,supporting 128-byte packets and CRC check. The sending program is integrated in theHyperTerminal.You can use Xmodem to upgrade the Boot ROM program, V 2.41 program andconfiguration file.
