diff --git a/isisd/isis_constants.h b/isisd/isis_constants.h
index 1b75ba6..bb2c4b4 100644
--- a/isisd/isis_constants.h
+++ b/isisd/isis_constants.h
@@ -27,8 +27,10 @@
  * Architectural constant values from p. 35 of ISO/IEC 10589
  */
 
-#define MAX_LINK_METRIC               63
-#define MAX_PATH_METRIC               1023
+#define MAX_NARROW_LINK_METRIC        63
+#define MAX_NARROW_PATH_METRIC        1023
+#define MAX_WIDE_LINK_METRIC          0x00FFFFFF  /* RFC4444 */
+#define MAX_WIDE_PATH_METRIC          0xFE000000  /* RFC3787 */
 #define ISO_SAP                       0xFE
 #define INTRADOMAIN_ROUTEING_SELECTOR 0
 #define SEQUENCE_MODULUS              4294967296
@@ -38,7 +40,7 @@
  * implementation specific jitter values
  */
 
-#define IIH_JITTER                    25	/* % */
+#define IIH_JITTER                    10	/* % */
 #define MAX_AGE_JITTER                 5	/* % */
 #define MAX_LSP_GEN_JITTER             5	/* % */
 #define CSNP_JITTER                   10	/* % */
@@ -46,36 +48,59 @@
 
 #define RANDOM_SPREAD           100000.0
 
-/*
- * Default values
- * ISO - 10589
- * Section 7.3.21 - Parameters
- */
-#define MAX_AGE                       1200
-#define ZERO_AGE_LIFETIME             60
-#define MAX_LSP_GEN_INTERVAL          900
-#define MIN_LSP_GEN_INTERVAL          30
-#define MIN_LSP_TRANS_INTERVAL        5
-#define ISIS_MIN_LSP_LIFETIME         380
-#define CSNP_INTERVAL                 10
-#define PSNP_INTERVAL                 2
-#define ISIS_MAX_PATH_SPLITS          3
-
 #define ISIS_LEVELS                   2
 #define ISIS_LEVEL1                   1
 #define ISIS_LEVEL2                   2
 
-#define HELLO_INTERVAL                10
-#define HELLO_MINIMAL HELLO_INTERVAL
-#define HELLO_MULTIPLIER              3
+/*
+ * Default values
+ * ISO - 10589 Section 7.3.21 - Parameters
+ * RFC 4444
+ */
+#define MAX_AGE                       1200
+#define ZERO_AGE_LIFETIME             60
+#define MIN_LSP_LIFETIME              350
+#define MAX_LSP_LIFETIME              65535
+#define DEFAULT_LSP_LIFETIME          1200
+
+#define MIN_MAX_LSP_GEN_INTERVAL      1
+#define MAX_MAX_LSP_GEN_INTERVAL      65235
+#define DEFAULT_MAX_LSP_GEN_INTERVAL  900
+
+#define MIN_MIN_LSP_GEN_INTERVAL      1
+#define MAX_MIN_LSP_GEN_INTERVAL      120  /* RFC 4444 says 65535 */
+#define DEFAULT_MIN_LSP_GEN_INTERVAL  30
+
+#define MIN_LSP_TRANS_INTERVAL        5
+
+#define MIN_CSNP_INTERVAL             1
+#define MAX_CSNP_INTERVAL             600
+#define DEFAULT_CSNP_INTERVAL         10
+
+#define MIN_PSNP_INTERVAL             1
+#define MAX_PSNP_INTERVAL             120
+#define DEFAULT_PSNP_INTERVAL         2
+
+#define MIN_HELLO_INTERVAL            1
+#define MAX_HELLO_INTERVAL            600
+#define DEFAULT_HELLO_INTERVAL        3
+
+#define MIN_HELLO_MULTIPLIER          2
+#define MAX_HELLO_MULTIPLIER          100
+#define DEFAULT_HELLO_MULTIPLIER      10
+
+#define MIN_PRIORITY                  0
+#define MAX_PRIORITY                  127
 #define DEFAULT_PRIORITY              64
-/* different vendors implement different values 5-10 on average */
-#define LSP_GEN_INTERVAL_DEFAULT      10
-#define LSP_INTERVAL                  33	/* msecs */
-#define DEFAULT_CIRCUIT_METRICS 10
-#define METRICS_UNSUPPORTED 0x80
-#define PERIODIC_SPF_INTERVAL         60	/* at the top of my head */
-#define MINIMUM_SPF_INTERVAL           5	/* .. same here          */
+
+/* min and max metric varies by new vs old metric types */
+#define DEFAULT_CIRCUIT_METRIC        10
+
+#define METRICS_UNSUPPORTED           0x80
+
+#define MINIMUM_SPF_INTERVAL          1
+
+#define ISIS_MAX_PATH_SPLITS          64
 
 /*
  * NLPID values
@@ -104,6 +129,7 @@
 
 #define SNPA_ADDRSTRLEN 18
 #define ISIS_SYS_ID_LEN  6
+#define ISIS_NSEL_LEN    1
 #define SYSID_STRLEN    24
 
 /*
@@ -136,8 +162,8 @@
  * packets, using isomtu = mtu - LLC_LEN
  */
 #define ISO_MTU(C) \
-          (C->circ_type==CIRCUIT_T_BROADCAST) ? \
-          (C->interface->mtu - LLC_LEN) : (C->interface->mtu)
+          ((if_is_broadcast ((C)->interface)) ? \
+           (C->interface->mtu - LLC_LEN) : (C->interface->mtu))
 
 #ifndef ETH_ALEN
 #define ETH_ALEN 6