diff --git a/isisd/isis_circuit.c b/isisd/isis_circuit.c
index 9fe11c2..81c6076 100644
--- a/isisd/isis_circuit.c
+++ b/isisd/isis_circuit.c
@@ -789,6 +789,8 @@
       THREAD_TIMER_OFF (circuit->u.bc.t_run_dr[1]);
       THREAD_TIMER_OFF (circuit->u.bc.t_refresh_pseudo_lsp[0]);
       THREAD_TIMER_OFF (circuit->u.bc.t_refresh_pseudo_lsp[1]);
+      circuit->lsp_regenerate_pending[0] = 0;
+      circuit->lsp_regenerate_pending[1] = 0;
     }
   else if (circuit->circ_type == CIRCUIT_T_P2P)
     {
diff --git a/isisd/isis_events.c b/isisd/isis_events.c
index 96d5762..0dee9e6 100644
--- a/isisd/isis_events.c
+++ b/isisd/isis_events.c
@@ -110,7 +110,10 @@
     }
 #endif /* HAVE_IPV6 */
 
+  sched_debug("ISIS (%s): Resigned from L%d - canceling LSP regeneration timer.",
+              area->area_tag, level);
   THREAD_TIMER_OFF (area->t_lsp_refresh[level - 1]);
+  area->lsp_regenerate_pending[level - 1] = 0;
 }
 
 void
@@ -245,6 +248,7 @@
       THREAD_TIMER_OFF (circuit->u.bc.t_send_lan_hello[idx]);
       THREAD_TIMER_OFF (circuit->u.bc.t_run_dr[idx]);
       THREAD_TIMER_OFF (circuit->u.bc.t_refresh_pseudo_lsp[idx]);
+      circuit->lsp_regenerate_pending[idx] = 0;
       circuit->u.bc.run_dr_elect[idx] = 0;
       list_delete (circuit->u.bc.lan_neighs[idx]);
       circuit->u.bc.lan_neighs[idx] = NULL;
diff --git a/isisd/isis_lsp.c b/isisd/isis_lsp.c
index 74a86c8..9ac0221 100644
--- a/isisd/isis_lsp.c
+++ b/isisd/isis_lsp.c
@@ -1681,10 +1681,13 @@
   lsp_build (newlsp, area);
   /* time to calculate our checksum */
   lsp_seqnum_update (newlsp);
+  newlsp->last_generated = time(NULL);
   lsp_set_all_srmflags (newlsp);
 
   refresh_time = lsp_refresh_time (newlsp, rem_lifetime);
+
   THREAD_TIMER_OFF (area->t_lsp_refresh[level - 1]);
+  area->lsp_regenerate_pending[level - 1] = 0;
   if (level == IS_LEVEL_1)
     THREAD_TIMER_ON (master, area->t_lsp_refresh[level - 1],
                      lsp_l1_refresh, area, refresh_time);
@@ -1704,6 +1707,8 @@
                   ntohs (newlsp->lsp_header->rem_lifetime),
                   refresh_time);
     }
+  sched_debug("ISIS (%s): Built L%d LSP. Set triggered regenerate to non-pending.",
+              area->area_tag, level);
 
   return ISIS_OK;
 }
@@ -1766,6 +1771,7 @@
   else if (level == IS_LEVEL_2)
     THREAD_TIMER_ON (master, area->t_lsp_refresh[level - 1],
                      lsp_l2_refresh, area, refresh_time);
+  area->lsp_regenerate_pending[level - 1] = 0;
 
   if (isis->debugs & DEBUG_UPDATE_PACKETS)
     {
@@ -1779,6 +1785,8 @@
                   ntohs (lsp->lsp_header->rem_lifetime),
                   refresh_time);
     }
+  sched_debug("ISIS (%s): Rebuilt L%d LSP. Set triggered regenerate to non-pending.",
+              area->area_tag, level);
 
   return ISIS_OK;
 }
@@ -1800,6 +1808,7 @@
   if ((area->is_type & IS_LEVEL_1) == 0)
     return ISIS_ERROR;
 
+  sched_debug("ISIS (%s): LSP L1 refresh timer expired. Refreshing LSP...", area->area_tag);
   return lsp_regenerate (area, IS_LEVEL_1);
 }
 
@@ -1817,6 +1826,7 @@
   if ((area->is_type & IS_LEVEL_2) == 0)
     return ISIS_ERROR;
 
+  sched_debug("ISIS (%s): LSP L2 refresh timer expired. Refreshing LSP...", area->area_tag);
   return lsp_regenerate (area, IS_LEVEL_2);
 }
 
@@ -1826,6 +1836,7 @@
   struct isis_lsp *lsp;
   u_char id[ISIS_SYS_ID_LEN + 2];
   time_t now, diff;
+  long timeout;
   struct listnode *cnode;
   struct isis_circuit *circuit;
   int lvl;
@@ -1833,6 +1844,9 @@
   if (area == NULL)
     return ISIS_ERROR;
 
+  sched_debug("ISIS (%s): Scheduling regeneration of %s LSPs, %sincluding PSNs",
+            area->area_tag, circuit_t2string(level), all_pseudo ? "" : "not ");
+
   memcpy (id, isis->sysid, ISIS_SYS_ID_LEN);
   LSP_PSEUDO_ID (id) = LSP_FRAGMENT (id) = 0;
   now = time (NULL);
@@ -1842,29 +1856,38 @@
       if (!((level & lvl) && (area->is_type & lvl)))
         continue;
 
+      sched_debug("ISIS (%s): Checking whether L%d needs to be scheduled",
+                  area->area_tag, lvl);
+
       if (area->lsp_regenerate_pending[lvl - 1])
-        continue;
+        {
+          struct timeval remain = thread_timer_remain(area->t_lsp_refresh[lvl - 1]);
+          sched_debug("ISIS (%s): Regeneration is already pending, nothing todo."
+                      " (Due in %lld.%03lld seconds)", area->area_tag,
+                      (long long)remain.tv_sec, (long long)remain.tv_usec / 1000);
+          continue;
+        }
 
       lsp = lsp_search (id, area->lspdb[lvl - 1]);
       if (!lsp)
-        continue;
+        {
+          sched_debug("ISIS (%s): We do not have any LSPs to regenerate, nothing todo.",
+                      area->area_tag);
+          continue;
+        }
 
       /*
        * Throttle avoidance
        */
+      sched_debug("ISIS (%s): Will schedule regen timer. Last run was: %lld, Now is: %lld",
+                  area->area_tag, (long long)lsp->last_generated, (long long)now);
       THREAD_TIMER_OFF (area->t_lsp_refresh[lvl - 1]);
       diff = now - lsp->last_generated;
       if (diff < area->lsp_gen_interval[lvl - 1])
         {
-          area->lsp_regenerate_pending[lvl - 1] = 1;
-          if (lvl == IS_LEVEL_1)
-            THREAD_TIMER_ON (master, area->t_lsp_refresh[lvl - 1],
-                             lsp_l1_refresh, area,
-                             area->lsp_gen_interval[lvl - 1] - diff);
-          else if (lvl == IS_LEVEL_2)
-            THREAD_TIMER_ON (master, area->t_lsp_refresh[lvl - 1],
-                             lsp_l2_refresh, area,
-                             area->lsp_gen_interval[lvl - 1] - diff);
+          timeout = 1000 * (area->lsp_gen_interval[lvl - 1] - diff);
+          sched_debug("ISIS (%s): Scheduling in %ld ms to match configured lsp_gen_interval",
+                      area->area_tag, timeout);
         }
       else
         {
@@ -1873,13 +1896,21 @@
            * directly. However if the lsp_regenerate call is queued for
            * later execution it works.
            */
-          area->lsp_regenerate_pending[lvl - 1] = 1;
-          if (lvl == IS_LEVEL_1)
-            THREAD_TIMER_ON (master, area->t_lsp_refresh[lvl - 1],
-                             lsp_l1_refresh, area, 0);
-          else if (lvl == IS_LEVEL_2)
-            THREAD_TIMER_ON (master, area->t_lsp_refresh[lvl - 1],
-                             lsp_l2_refresh, area, 0);
+          timeout = 100;
+          sched_debug("ISIS (%s): Last generation was more than lsp_gen_interval ago."
+                      " Scheduling for execution in %ld ms.", area->area_tag, timeout);
+        }
+
+      area->lsp_regenerate_pending[lvl - 1] = 1;
+      if (lvl == IS_LEVEL_1)
+        {
+          THREAD_TIMER_MSEC_ON(master, area->t_lsp_refresh[lvl - 1],
+                               lsp_l1_refresh, area, timeout);
+        }
+      else if (lvl == IS_LEVEL_2)
+        {
+          THREAD_TIMER_MSEC_ON(master, area->t_lsp_refresh[lvl - 1],
+                               lsp_l2_refresh, area, timeout);
         }
     }
 
@@ -2231,13 +2262,18 @@
   struct isis_lsp *lsp;
   u_char lsp_id[ISIS_SYS_ID_LEN + 2];
   time_t now, diff;
+  long timeout;
   int lvl;
+  struct isis_area *area = circuit->area;
 
   if (circuit == NULL ||
       circuit->circ_type != CIRCUIT_T_BROADCAST ||
       circuit->state != C_STATE_UP)
     return ISIS_OK;
 
+  sched_debug("ISIS (%s): Scheduling regeneration of %s pseudo LSP for interface %s",
+              area->area_tag, circuit_t2string(level), circuit->interface->name);
+
   memcpy (lsp_id, isis->sysid, ISIS_SYS_ID_LEN);
   LSP_PSEUDO_ID (lsp_id) = circuit->circuit_id;
   LSP_FRAGMENT (lsp_id) = 0;
@@ -2245,39 +2281,74 @@
 
   for (lvl = IS_LEVEL_1; lvl <= IS_LEVEL_2; lvl++)
     {
-      if (!((level & lvl) && (circuit->is_type & lvl)))
-        continue;
+      sched_debug("ISIS (%s): Checking whether L%d pseudo LSP needs to be scheduled",
+                  area->area_tag, lvl);
 
-      if (circuit->u.bc.is_dr[lvl - 1] == 0 ||
-          circuit->lsp_regenerate_pending[lvl - 1])
-        continue;
+      if (!((level & lvl) && (circuit->is_type & lvl)))
+        {
+          sched_debug("ISIS (%s): Level is not active on circuit",
+                      area->area_tag);
+          continue;
+        }
+
+      if (circuit->u.bc.is_dr[lvl - 1] == 0)
+        {
+          sched_debug("ISIS (%s): This IS is not DR, nothing to do.",
+                      area->area_tag);
+          continue;
+        }
+
+      if (circuit->lsp_regenerate_pending[lvl - 1])
+        {
+          struct timeval remain =
+                  thread_timer_remain(circuit->u.bc.t_refresh_pseudo_lsp[lvl - 1]);
+          sched_debug("ISIS (%s): Regenerate is already pending, nothing todo."
+                      " (Due in %lld.%03lld seconds)", area->area_tag,
+                      (long long)remain.tv_sec, (long long)remain.tv_usec/1000);
+          continue;
+        }
 
       lsp = lsp_search (lsp_id, circuit->area->lspdb[lvl - 1]);
       if (!lsp)
-        continue;
+        {
+          sched_debug("ISIS (%s): Pseudonode LSP does not exist yet, nothing to regenerate.",
+                      area->area_tag);
+          continue;
+        }
 
       /*
        * Throttle avoidance
        */
+      sched_debug("ISIS (%s): Will schedule PSN regen timer. Last run was: %lld, Now is: %lld",
+                  area->area_tag, (long long)lsp->last_generated, (long long) now);
       THREAD_TIMER_OFF (circuit->u.bc.t_refresh_pseudo_lsp[lvl - 1]);
       diff = now - lsp->last_generated;
       if (diff < circuit->area->lsp_gen_interval[lvl - 1])
         {
-          circuit->lsp_regenerate_pending[lvl - 1] = 1;
-          if (lvl == IS_LEVEL_1)
-            THREAD_TIMER_ON (master,
-                             circuit->u.bc.t_refresh_pseudo_lsp[lvl - 1],
-                             lsp_l1_refresh_pseudo, circuit,
-                             circuit->area->lsp_gen_interval[lvl - 1] - diff);
-          else if (lvl == IS_LEVEL_2)
-            THREAD_TIMER_ON (master,
-                             circuit->u.bc.t_refresh_pseudo_lsp[lvl - 1],
-                             lsp_l2_refresh_pseudo, circuit,
-                             circuit->area->lsp_gen_interval[lvl - 1] - diff);
+          timeout = 1000 * (circuit->area->lsp_gen_interval[lvl - 1] - diff);
+          sched_debug("ISIS (%s): Sechduling in %ld ms to match configured lsp_gen_interval",
+                      area->area_tag, timeout);
         }
       else
         {
-          lsp_regenerate_pseudo (circuit, lvl);
+          timeout = 100;
+          sched_debug("ISIS (%s): Last generation was more than lsp_gen_interval ago."
+                      " Scheduling for execution in %ld ms.", area->area_tag, timeout);
+        }
+
+      circuit->lsp_regenerate_pending[lvl - 1] = 1;
+
+      if (lvl == IS_LEVEL_1)
+        {
+          THREAD_TIMER_MSEC_ON(master,
+                               circuit->u.bc.t_refresh_pseudo_lsp[lvl - 1],
+                               lsp_l1_refresh_pseudo, circuit, timeout);
+        }
+      else if (lvl == IS_LEVEL_2)
+        {
+          THREAD_TIMER_MSEC_ON(master,
+                               circuit->u.bc.t_refresh_pseudo_lsp[lvl - 1],
+                               lsp_l2_refresh_pseudo, circuit, timeout);
         }
     }
 
diff --git a/isisd/isisd.c b/isisd/isisd.c
index b601032..0a5286e 100644
--- a/isisd/isisd.c
+++ b/isisd/isisd.c
@@ -774,6 +774,8 @@
     vty_out (vty, "IS-IS Packet dump debugging is %s%s", onoffs, VTY_NEWLINE);
   if (flags & DEBUG_LSP_GEN)
     vty_out (vty, "IS-IS LSP generation debugging is %s%s", onoffs, VTY_NEWLINE);
+  if (flags & DEBUG_LSP_SCHED)
+    vty_out (vty, "IS-IS LSP scheduling debugging is %s%s", onoffs, VTY_NEWLINE);
 }
 
 DEFUN (show_debugging,
@@ -865,6 +867,11 @@
       vty_out (vty, "debug isis lsp-gen%s", VTY_NEWLINE);
       write++;
     }
+  if (flags & DEBUG_LSP_SCHED)
+    {
+      vty_out (vty, "debug isis lsp-sched%s", VTY_NEWLINE);
+      write++;
+    }
 
   return write;
 }
@@ -1207,6 +1214,32 @@
   return CMD_SUCCESS;
 }
 
+DEFUN (debug_isis_lsp_sched,
+       debug_isis_lsp_sched_cmd,
+       "debug isis lsp-sched",
+       DEBUG_STR
+       "IS-IS information\n"
+       "IS-IS scheduling of LSP generation\n")
+{
+  isis->debugs |= DEBUG_LSP_SCHED;
+  print_debug (vty, DEBUG_LSP_SCHED, 1);
+
+  return CMD_SUCCESS;
+}
+
+DEFUN (no_debug_isis_lsp_sched,
+       no_debug_isis_lsp_sched_cmd,
+       "no debug isis lsp-gen",
+       UNDEBUG_STR
+       "IS-IS information\n"
+       "IS-IS scheduling of LSP generation\n")
+{
+  isis->debugs &= ~DEBUG_LSP_SCHED;
+  print_debug (vty, DEBUG_LSP_SCHED, 0);
+
+  return CMD_SUCCESS;
+}
+
 DEFUN (show_hostname,
        show_hostname_cmd,
        "show isis hostname",
@@ -3295,6 +3328,8 @@
   install_element (ENABLE_NODE, &no_debug_isis_packet_dump_cmd);
   install_element (ENABLE_NODE, &debug_isis_lsp_gen_cmd);
   install_element (ENABLE_NODE, &no_debug_isis_lsp_gen_cmd);
+  install_element (ENABLE_NODE, &debug_isis_lsp_sched_cmd);
+  install_element (ENABLE_NODE, &no_debug_isis_lsp_sched_cmd);
 
   install_element (CONFIG_NODE, &debug_isis_adj_cmd);
   install_element (CONFIG_NODE, &no_debug_isis_adj_cmd);
@@ -3322,6 +3357,8 @@
   install_element (CONFIG_NODE, &no_debug_isis_packet_dump_cmd);
   install_element (CONFIG_NODE, &debug_isis_lsp_gen_cmd);
   install_element (CONFIG_NODE, &no_debug_isis_lsp_gen_cmd);
+  install_element (CONFIG_NODE, &debug_isis_lsp_sched_cmd);
+  install_element (CONFIG_NODE, &no_debug_isis_lsp_sched_cmd);
 
   install_element (CONFIG_NODE, &router_isis_cmd);
   install_element (CONFIG_NODE, &no_router_isis_cmd);
diff --git a/isisd/isisd.h b/isisd/isisd.h
index 51a72ab..96c3ba3 100644
--- a/isisd/isisd.h
+++ b/isisd/isisd.h
@@ -97,6 +97,17 @@
   struct flags flags;
   struct thread *t_tick;	/* LSP walker */
   struct thread *t_lsp_refresh[ISIS_LEVELS];
+  /* t_lsp_refresh is used in two ways:
+   * a) regular refresh of LSPs
+   * b) (possibly throttled) updates to LSPs
+   *
+   * The lsp_regenerate_pending flag tracks whether the timer is active
+   * for the a) or the b) case.
+   *
+   * It is of utmost importance to clear this flag when the timer is
+   * rescheduled for normal refresh, because otherwise, updates will
+   * be delayed until the next regular refresh.
+   */
   int lsp_regenerate_pending[ISIS_LEVELS];
 
   /*
@@ -167,6 +178,7 @@
 #define DEBUG_ZEBRA                      (1<<11)
 #define DEBUG_PACKET_DUMP                (1<<12)
 #define DEBUG_LSP_GEN                    (1<<13)
+#define DEBUG_LSP_SCHED                  (1<<14)
 
 #define lsp_debug(...) \
   do \
@@ -176,4 +188,12 @@
     } \
   while (0)
 
+#define sched_debug(...) \
+  do \
+    { \
+      if (isis->debugs & DEBUG_LSP_SCHED) \
+        zlog_debug(__VA_ARGS__); \
+    } \
+  while (0)
+
 #endif /* ISISD_H */