1、配置ip地址：
rommon 2 > IP_ADDRESS=192.168.1.1
rommon 3 > IP_SUBNET_MASK=255.255.255.0
2、配置网关： DEFAULT_GATEWAY: 192.168.1.254
3、服务器IP：TFTP_SERVER: 192.168.1.254
4、下载IOS：TFTP_FILE: c2600-i-mz.122-28.bin
5、确认：rommon 10 > TFTPDNLD #根据以上参数寻找TFTP服务器
IP_ADDRESS: 192.168.1.1
IP_SUBNET_MASK: 255.255.255.0
DEFAULT_GATEWAY: 192.168.1.254
TFTP_SERVER: 192.168.1.254
TFTP_FILE: c2600-i-mz.122-28.bin
Invoke this command for disaster recovery only.
WARNING: all existing data in all partitions on flash will be lost!
Do you wish to continue? y/n: [n]: y