rommon 11 > IP_ADDRESS=192.168.1.1
rommon 12 > IP_SUBNET_MASK=255.255.255.0
rommon 13 > DEFAULT_GATEWAY=192.168.1.254
rommon 14 > TFTP_SERVER=192.168.1.23
rommon 15 > TFTP_FILE=image.bin
rommon 16 > tftpdnld
Using the boot manager (4500/6500) : http://www.cisco.com/en/US/products/hw/routers/ps214/products_tech_note09186a0080110ed1.shtml