diff --git a/isisd/isis_csm.h b/isisd/isis_csm.h
new file mode 100644
index 0000000..23cc215
--- /dev/null
+++ b/isisd/isis_csm.h
@@ -0,0 +1,47 @@
+/*
+ * IS-IS Rout(e)ing protocol - isis_csm.h
+ *                             IS-IS circuit state machine
+ *
+ * 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.
+ */
+#ifndef _ZEBRA_ISIS_CSM_H
+#define _ZEBRA_ISIS_CSM_H
+
+/*
+ * Circuit states
+ */
+#define C_STATE_NA   0
+#define C_STATE_INIT 1 /* Connected to interface */
+#define C_STATE_CONF 2 /* Configured for ISIS    */
+#define C_STATE_UP   3 /* CONN | CONF            */ 
+
+/*
+ * Circuit events
+ */
+#define ISIS_ENABLE    1
+#define IF_UP_FROM_Z   2
+#define ISIS_DISABLE   3
+#define IF_DOWN_FROM_Z 4
+
+struct isis_circuit *isis_csm_state_change (int event, 
+                                            struct isis_circuit *circuit, 
+                                            void *arg);
+
+#endif /* _ZEBRA_ISIS_CSM_H */