diff --git a/ryu/app/simple_switch_igmp.py b/ryu/app/simple_switch_igmp.py
index b1b014f01..0ab1969ef 100644
--- a/ryu/app/simple_switch_igmp.py
+++ b/ryu/app/simple_switch_igmp.py
@@ -22,6 +22,7 @@
 from ryu.lib import addrconv
 from ryu.lib import igmplib
 from ryu.lib.dpid import str_to_dpid
+from ryu.ofproto.ofproto_parser import buffer
 
 
 class SimpleSwitchIgmp(app_manager.RyuApp):