Operation Manual – System Maintenance and DebuggingH3C S7500 Series Ethernet SwitchesChapter 1 Boot ROM and Host SoftwareLoading1-3Press Ctrl+B to enter Boot Menu... 0Press . The system displays:Password :Note:To enter the Boot Menu, you should press within five seconds after theinformation “Press Ctrl-B to enter Boot Menu...” appears. Otherwise, the system startsto decompress the program; and if you want to enter the Boot Menu at this time, you willhave to restart the switch.Input the correct Boot ROM password (no password is need by default). The systementers the Boot Menu:BOOT MENU1. Download application file to flash2. Select application file to boot3. Display all files in flash4. Delete file from flash5. Modify bootrom password0. RebootEnter your choice(0-5):1.2.2 Loading Software Using XMODEM through Console PortI. Introduction to XMODEMXMODEM is a file transfer protocol that is widely used due to its simplicity and goodperformance. XMODEM transfers files via Console port. It supports two types of datapackets (128 bytes and 1 KB), two check methods (checksum and CRC), and multipleattempts of error packet retransmission (generally the maximum number ofretransmission attempts is ten).The XMODEM transmission procedure is completed by a receiving program and asending program: The receiving program sends negotiation characters to negotiate apacket checking method. After the negotiation, the sending program starts to transmitdata packets. When receiving a complete packet, the receiving program checks thepacket using the agreed method. If the check succeeds, the receiving program sendsan acknowledgement character and the sending program proceeds to send anotherpacket; otherwise, the receiving program sends a negative acknowledgementcharacter and the sending program retransmits the packet.
