diff --git a/isisd/isis_common.h b/isisd/isis_common.h
new file mode 100644
index 0000000..951e637
--- /dev/null
+++ b/isisd/isis_common.h
@@ -0,0 +1,65 @@
+/*
+ * IS-IS Rout(e)ing protocol - isis_common.h  
+ *                             some common data structures
+ *
+ * Copyright (C) 2001,2002   Sampo Saaristo
+ *                           Tampere University of Technology      
+ *                           Institute of Communications Engineering
+ *
+ * This program is free software; you can redistribute it and/or modify it 
+ * under the terms of the GNU General Public Licenseas published by the Free 
+ * Software Foundation; either version 2 of the License, or (at your option) 
+ * any later version.
+ *
+ * This program 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 this program; if not, write to the Free Software Foundation, Inc., 
+ * 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+ */
+
+/*
+ * Area Address
+ */ 
+struct area_addr {
+  u_char             addr_len;
+  u_char             area_addr[20];
+};
+
+struct isis_passwd {
+  u_char len;
+#define ISIS_PASSWD_TYPE_UNUSED   0
+#define ISIS_PASSWD_TYPE_CLEARTXT 1
+#define ISIS_PASSWD_TYPE_PRIVATE  255
+  u_char type;
+  u_char passwd[255];
+};
+
+/*
+ * (Dynamic) Hostname
+ * one struct for cache list
+ * one struct for LSP TLV
+ */
+struct hostname {
+  u_char namelen;
+  u_char name[255];
+};
+
+/*
+ * Supported Protocol IDs
+ */
+struct nlpids {
+  u_char count;
+  u_char nlpids[4]; /* FIXME: enough ? */ 
+};
+
+/*
+ * Flags structure for SSN and SRM flags
+ */ 
+struct flags {
+  int maxindex;
+  struct list *free_idcs;
+};