diff --git a/openstack/03b-IPv6/icmpv6rpl.h b/openstack/03b-IPv6/icmpv6rpl.h
index f98f5d753b..8abcf7d28e 100644
--- a/openstack/03b-IPv6/icmpv6rpl.h
+++ b/openstack/03b-IPv6/icmpv6rpl.h
@@ -13,7 +13,7 @@
 //=========================== define ==========================================
 
 #define DIO_PERIOD             10000   // in miliseconds
-#define DAO_PERIOD             60000   // in miliseconds
+#define DAO_PERIOD             30000   // in miliseconds
 
 // Non-Storing Mode of Operation (1)
 #define MOP_DIO_A                 0<<5