I want to connect t wireless network (no password nedded)

I tried this

sudo iwconfig wlan0 essid network-essid

and tried this

  in /etc/network/interfaces

auto wlan0
allow-hotplug wlan0
iface wlan0 inet dhcp
       wpa-ssid ="network-essid"

but ifconfig still

wlan0     Link encap:Ethernet  HWaddr e8:94:f6:16:7f:f1  
          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)

I want to connect to a wireless network (no password needed)

I tried this

sudo iwconfig wlan0 essid network-essid

and tried this, in /etc/network/interfaces

auto wlan0
allow-hotplug wlan0
iface wlan0 inet dhcp
       wpa-ssid ="network-essid"

but ifconfig still shows

wlan0     Link encap:Ethernet  HWaddr e8:94:f6:16:7f:f1  
          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)