NFS挂载根文件系统显示不成功该怎么办？

用NFS挂载根文件系统挂载不成功，内核启动时显示：IP-Config: Device `off' not found.Looking up port of RPC 100003/2 on 192.168.0.101
rPCBind: server 192.168.0.101 not responding, timed out


我的UBOOT配置如下：setbootargs noinitrd root=/dev/nfs nfsroot=192.168.0.101:/work/nfs_root/tmp/fs_mini_mdev ip=192.168.0.103:192.168.0.101:192.168.0.1:255.255.255.0:eth0:offinit=/linuxrc console=ttySAC0