2607/tcp is already used by ospfapi.

Let's use 2608/tcp for isisd.

SERVICES

@@ -15,4 +15,5 @@ ripng		2603/tcp
 ospfd		2604/tcp
 bgpd		2605/tcp
 ospf6d		2606/tcp
-isisd		2607/tcp
+ospfapi		2607/tcp
+isisd		2608/tcp

isisd/isis_main.c

@@ -47,7 +47,7 @@
 /* Default configuration file name */
 #define ISISD_DEFAULT_CONFIG "isisd.conf"
 /* Default vty port */
-#define ISISD_VTY_PORT       2607
+#define ISISD_VTY_PORT       2608
 
 /* isisd privileges */
 zebra_capabilities_t _caps_p [] =