diff --git a/ospf6d/ospf6_interface.h b/ospf6d/ospf6_interface.h
new file mode 100644
index 0000000..a96ef25
--- /dev/null
+++ b/ospf6d/ospf6_interface.h
@@ -0,0 +1,153 @@
+/*
+ * Copyright (C) 1999 Yasuhiro Ohara
+ *
+ * This file is part of GNU Zebra.
+ *
+ * GNU Zebra is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2, or (at your option) any
+ * later version.
+ *
+ * GNU Zebra is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with GNU Zebra; see the file COPYING.  If not, write to the 
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330, 
+ * Boston, MA 02111-1307, USA.  
+ */
+
+#ifndef OSPF6_INTERFACE_H
+#define OSPF6_INTERFACE_H
+
+#include "ospf6_message.h"
+
+/* This file defines interface data structure. */
+
+struct ospf6_interface
+{
+  /* IF info from zebra */
+  struct interface *interface;
+
+  /* back pointer */
+  struct ospf6_area *area;
+
+  /* list of ospf6 neighbor */
+  list neighbor_list;
+
+  /* linklocal address of this I/F */
+  struct in6_addr *lladdr;
+
+  /* Interface ID; same as ifindex */
+  u_int32_t if_id;
+
+  /* ospf6 instance id */
+  u_char instance_id;
+
+  /* I/F transmission delay */
+  u_int32_t transdelay;
+
+  /* Router Priority */
+  u_char priority;
+
+  /* Timers */
+  u_int16_t hello_interval;
+  u_int16_t dead_interval;
+  u_int32_t rxmt_interval;
+
+  /* Cost */
+  u_int32_t cost;
+
+  /* I/F MTU */
+  u_int32_t ifmtu;
+
+  /* Interface State */
+  u_char state;
+
+  /* OSPF6 Interface flag */
+  char flag;
+
+  /* Decision of DR Election */
+  u_int32_t dr;
+  u_int32_t bdr;
+  u_int32_t prevdr;
+  u_int32_t prevbdr;
+
+  /* Ongoing Tasks */
+  struct thread *thread_send_hello;
+  struct thread *thread_send_lsack_delayed;
+
+  /* LSAs to Delayed Acknowledge */
+  struct ospf6_lsdb *ack_list;
+
+  /* Linklocal LSA Database: includes Link-LSA */
+  struct ospf6_lsdb *lsdb;
+
+  /* statistics */
+  u_int ospf6_stat_dr_election;
+  u_int ospf6_stat_delayed_lsack;
+
+  struct ospf6_message_stat message_stat[OSPF6_MESSAGE_TYPE_MAX];
+
+  void (*foreach_nei) (struct ospf6_interface *, void *, int,
+                       void (*func) (void *, int, void *));
+
+  struct thread *maxage_remover;
+
+  /* route-map to filter connected prefix */
+  char *plist_name;
+};
+
+extern char *ospf6_interface_state_string[];
+
+#define OSPF6_INTERFACE_FLAG_PASSIVE      0x01
+#define OSPF6_INTERFACE_FLAG_FORCE_PREFIX 0x02
+
+
+/* Function Prototypes */
+
+void
+ospf6_interface_schedule_maxage_remover (void *arg, int val, void *obj);
+
+struct ospf6_interface *
+ospf6_interface_create (struct interface *);
+void
+ospf6_interface_delete (struct ospf6_interface *);
+
+struct ospf6_interface *
+ospf6_interface_lookup_by_index (int);
+struct ospf6_interface *
+ospf6_interface_lookup_by_name (char *);
+
+void ospf6_interface_if_add (struct interface *);
+void ospf6_interface_if_del (struct interface *);
+void ospf6_interface_state_update (struct interface *);
+void ospf6_interface_address_update (struct interface *);
+
+void ospf6_interface_init ();
+
+#if 0
+int
+ospf6_interface_count_neighbor_in_state (u_char state,
+                                         struct ospf6_interface *o6i);
+int
+ospf6_interface_count_full_neighbor (struct ospf6_interface *);
+#endif
+
+int ospf6_interface_is_enabled (u_int32_t ifindex);
+
+void
+ospf6_interface_delayed_ack_add (struct ospf6_lsa *lsa,
+                                 struct ospf6_interface *o6i);
+void
+ospf6_interface_delayed_ack_remove (struct ospf6_lsa *lsa,
+                                    struct ospf6_interface *o6i);
+
+void
+ospf6_interface_statistics_show (struct vty *vty,
+                                 struct ospf6_interface *o6i);
+
+#endif /* OSPF6_INTERFACE_H */
+