ubuntu 12.04 networking restart

If I suspend my computer at school, I can not connect to the internet when I get home. I searched on line and found the command at terminal:
 /etc/init.d/networking start

but it did not work, it says the command is deprecated....

Instead, type

tommy@tommy-ThinkPad-T420:~$ ifconfig
eth0      Link encap:Ethernet  HWaddr 00:21:cc:71:ab:50  
          UP BROADCAST MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)
          Interrupt:20 Memory:f2500000-f2520000 

lo        Link encap:Local Loopback  
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:3526 errors:0 dropped:0 overruns:0 frame:0
          TX packets:3526 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:440923 (440.9 KB)  TX bytes:440923 (440.9 KB)

wlan0     Link encap:Ethernet  HWaddr 60:d8:19:c7:42:9b  
          UP BROADCAST MULTICAST  MTU:1500  Metric:1
          RX packets:238663 errors:0 dropped:0 overruns:0 frame:0
          TX packets:168877 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:310906582 (310.9 MB)  TX bytes:20035785 (20.0 MB)

tommy@tommy-ThinkPad-T420:~$ sudo ifconfig wlan0 down
[sudo] password for tommy: 
tommy@tommy-ThinkPad-T420:~$ sudo ifconfig wlan0 up

Now, I had no problem! Thanks to my roommate YuRen!