diff --git a/doc/developer/ospf-ls-retrans.rst b/doc/developer/ospf-ls-retrans.rst
new file mode 100644
index 0000000000..230d7a1c5d
--- /dev/null
+++ b/doc/developer/ospf-ls-retrans.rst
@@ -0,0 +1,69 @@
+OSPF Neighor Retransmission List
+================================
+
+Overview
+--------
+
+OSPF neighbor link-state retransmission lists are implemented using
+both a sparse Link State Database (LSDB) and a doubly-linked list.
+Rather than previous per-neighbor periodic timer, a per-neighbor
+timer is set to the expiration time of the next scheduled LSA
+retransmission.
+
+Sparse Link State Database (LSDB)
+---------------------------------
+
+When an explicit or implied acknowledgment is recieved from a
+neighbor in 2-way state or higher, the acknowledge LSA must be
+removed from the neighbor's link state retransmission list. In order
+to do this efficiently, a sparse LSDB is utilized. LSDB entries also
+include a pointer to the corresponding list entry so that it may be
+efficiently removed from the doubly-linked list.
+
+The sparse LSDB is implemented using the OSPF functions is
+ospf_lsdb.[c,h]. OSPF LSDBs are implemented as an array of route
+tables (lib/table.[c,h]). What is unique of the LS Retransmission
+list LSDB is that each entry also has a pointer into the doubly-linked
+list to facilitate fast deletions.
+
+Doubly-Linked List
+------------------
+
+In addition to the sparse LSDB, LSAs on a neighbor LS retransmission
+list are also maintained in a linked-list order chronologically
+with the LSA scheduled for the next retransmission at the head of
+the list.
+
+The doubly-link list is implemented using the dlist macros in
+lib/typesafe.h.
+
+LSA LS Retransmission List Addition
+------------------------------------
+
+When an LSA is added to a neighbor retransmission list, it is
+added to both the sparse LSDB and the doubly-linked list with a pointer
+in the LSDB route-table node to the list entry. The LSA is added to
+the tail of the list with the expiration time set to the current time
+with the retransmission interval added. If the neighbor retransmission
+timer is not set, it is set to expire at the time of the newly added
+LSA.
+
+LSA LS Retransmission List Deletion
+-----------------------------------
+
+When an LSA is deleted from a neighbor retransmission list, it is
+deleted from eboth the sparse LSDB and the doubly-linked list with the
+pointer the LSDB route-table node used to efficiently delete the entry
+from the list. If the LSA at the head of the list was removed, then
+the neighbor retransmission timer is reset to the expiration of the
+LSA at the head of the list or canceled if the list is empty.
+
+Neighbor LS Retransmission List Expiration
+------------------------------------------
+
+When the neighbor retransmission timer expires, the LSA at the top of
+list and any in a configured window (e.g., 50 milliseconds) are
+retransmitted. The LSAs that have been retransmitted are removed from
+the list and readded to the tail of the list with a new expiration time
+which is retransmit-interval seconds in the future.
+
diff --git a/doc/developer/ospf.rst b/doc/developer/ospf.rst
index 837a0bd185..da4802533c 100644
--- a/doc/developer/ospf.rst
+++ b/doc/developer/ospf.rst
@@ -8,6 +8,7 @@ OSPFD
    :maxdepth: 2
 
    ospf-api
+   ospf-ls-retrans
    ospf-sr
    cspf
 
diff --git a/doc/user/ospfd.rst b/doc/user/ospfd.rst
index 70c15e73de..b80adba7f0 100644
--- a/doc/user/ospfd.rst
+++ b/doc/user/ospfd.rst
@@ -738,7 +738,17 @@ Interfaces
    retransmitting Database Description and Link State Request packets. The
    default value is 5 seconds.
 
-.. clicmd:: ip ospf transmit-delay (1-65535) [A.B.C.D]
+.. clicmd:: ip ospf retransmit-window (20-1000)
+
+
+   Set number of milliseconds in the window for neighbor LSA retransmission.
+   When a neighbor Link State (LS) retransmission timer expires, LSAs scheduled
+   to be retransmitted within the number of milliseconds configured are
+   retransmitted to the neighbor. Any expiring after the window will be
+   retransmitted the next time the neighbor LS retransmission timer expires.
+   The default is 50 milliseconds.
+
+ .. clicmd:: ip ospf transmit-delay (1-65535) [A.B.C.D]
 
 
    Set number of seconds for InfTransDelay value. LSAs' age should be
diff --git a/lib/libospf.h b/lib/libospf.h
index 0ac490a00e..f2dc5d61d9 100644
--- a/lib/libospf.h
+++ b/lib/libospf.h
@@ -58,6 +58,7 @@ extern "C" {
 #define OSPF_HELLO_DELAY_DEFAULT           10
 #define OSPF_ROUTER_PRIORITY_DEFAULT        1
 #define OSPF_RETRANSMIT_INTERVAL_DEFAULT    5
+#define OSPF_RETRANSMIT_WINDOW_DEFAULT	    50 /* milliseconds */
 #define OSPF_TRANSMIT_DELAY_DEFAULT         1
 #define OSPF_DEFAULT_BANDWIDTH		 10000	/* Mbps */
 
diff --git a/ospfd/ospf_flood.c b/ospfd/ospf_flood.c
index e15871ac81..e9797ce935 100644
--- a/ospfd/ospf_flood.c
+++ b/ospfd/ospf_flood.c
@@ -1015,7 +1015,7 @@ void ospf_ls_request_delete(struct ospf_neighbor *nbr, struct ospf_lsa *lsa)
 	ospf_lsdb_delete(&nbr->ls_req, lsa);
 }
 
-/* Remove all LSA from neighbor's ls-requenst list. */
+/* Remove all LSAs from neighbor's ls-request list. */
 void ospf_ls_request_delete_all(struct ospf_neighbor *nbr)
 {
 	ospf_lsa_unlock(&nbr->ls_req_last);
@@ -1061,58 +1061,114 @@ int ospf_ls_retransmit_isempty(struct ospf_neighbor *nbr)
 /* Add LSA to be retransmitted to neighbor's ls-retransmit list. */
 void ospf_ls_retransmit_add(struct ospf_neighbor *nbr, struct ospf_lsa *lsa)
 {
-	struct ospf_lsa *old;
+	struct ospf_lsdb_linked_node *ls_rxmt_node;
+	struct ospf_lsa_list_entry *ls_rxmt_list_entry;
+	struct ospf_lsa *old = NULL;
+	bool rxmt_head_replaced = false;
 
-	old = ospf_ls_retransmit_lookup(nbr, lsa);
+	ls_rxmt_node = ospf_lsdb_linked_lookup(&nbr->ls_rxmt, lsa);
+	if (ls_rxmt_node)
+		old = ls_rxmt_node->info;
 
 	if (ospf_lsa_more_recent(old, lsa) < 0) {
 		if (old) {
 			old->retransmit_counter--;
+			if (ls_rxmt_node->lsa_list_entry ==
+			    ospf_lsa_list_first(&nbr->ls_rxmt_list))
+				rxmt_head_replaced = true;
+			ospf_lsa_list_del(&nbr->ls_rxmt_list,
+					  ls_rxmt_node->lsa_list_entry);
+			XFREE(MTYPE_OSPF_LSA_LIST, ls_rxmt_node->lsa_list_entry);
+			ospf_lsdb_delete(&nbr->ls_rxmt, old);
 			if (IS_DEBUG_OSPF(lsa, LSA_FLOODING))
-				zlog_debug("RXmtL(%lu)--, NBR(%pI4(%s)), LSA[%s]",
+				zlog_debug("RXmtL(%lu) NBR(%pI4(%s)) Old Delete LSA[%s] on Add",
 					   ospf_ls_retransmit_count(nbr),
 					   &nbr->router_id,
 					   ospf_get_name(nbr->oi->ospf),
-					   dump_lsa_key(old));
-			ospf_lsdb_delete(&nbr->ls_rxmt, old);
+					   dump_lsa_key(lsa));
+			ospf_lsa_unlock(&old);
 		}
 		lsa->retransmit_counter++;
+		ls_rxmt_list_entry = XCALLOC(MTYPE_OSPF_LSA_LIST,
+					     sizeof(struct ospf_lsa_list_entry));
 		/*
-		 * We cannot make use of the newly introduced callback function
-		 * "lsdb->new_lsa_hook" to replace debug output below, just
-		 * because
-		 * it seems no simple and smart way to pass neighbor information
-		 * to
-		 * the common function "ospf_lsdb_add()" -- endo.
+		 * Set the LSA retransmission time for the neighbor;
 		 */
-		if (IS_DEBUG_OSPF(lsa, LSA_FLOODING))
-			zlog_debug("RXmtL(%lu)++, NBR(%pI4(%s)), LSA[%s]",
-				   ospf_ls_retransmit_count(nbr),
-				   &nbr->router_id,
-				   ospf_get_name(nbr->oi->ospf),
-				   dump_lsa_key(lsa));
+		monotime(&ls_rxmt_list_entry->list_entry_time);
+		ls_rxmt_list_entry->list_entry_time.tv_sec += nbr->v_ls_rxmt;
+
+		/*
+		 * Add the LSA to the neighbor retransmission list.
+		 */
+		ls_rxmt_list_entry->lsa = ospf_lsa_lock(lsa);
+		ospf_lsa_list_add_tail(&nbr->ls_rxmt_list, ls_rxmt_list_entry);
 		ospf_lsdb_add(&nbr->ls_rxmt, lsa);
+
+		/*
+		 * Look up the newly added node and set the list pointer.
+		 */
+		ls_rxmt_node = ospf_lsdb_linked_lookup(&nbr->ls_rxmt, lsa);
+		ls_rxmt_node->lsa_list_entry = ls_rxmt_list_entry;
+
+		if (IS_DEBUG_OSPF(lsa, LSA_FLOODING))
+			zlog_debug("RXmtL(%lu) NBR(%pI4(%s)) Add LSA[%s] retrans at (%ld/%ld)",
+				   ospf_ls_retransmit_count(nbr),
+				   &nbr->router_id, ospf_get_name(nbr->oi->ospf),
+				   dump_lsa_key(lsa),
+				   (long)ls_rxmt_list_entry->list_entry_time
+					   .tv_sec,
+				   (long)ls_rxmt_list_entry->list_entry_time
+					   .tv_usec);
+		/*
+		 * Reset the neighbor LSA retransmission timer if isn't currently
+		 * running or the LSA at the head of the list was updated.
+		 */
+		if (!nbr->t_ls_rxmt || rxmt_head_replaced)
+			ospf_ls_retransmit_set_timer(nbr);
 	}
 }
 
 /* Remove LSA from neibghbor's ls-retransmit list. */
 void ospf_ls_retransmit_delete(struct ospf_neighbor *nbr, struct ospf_lsa *lsa)
 {
-	if (ospf_ls_retransmit_lookup(nbr, lsa)) {
+	struct ospf_lsdb_linked_node *ls_rxmt_node;
+
+	ls_rxmt_node = ospf_lsdb_linked_lookup(&nbr->ls_rxmt, lsa);
+
+	if (ls_rxmt_node) {
+		bool rxmt_timer_reset;
+
+		if (ls_rxmt_node->lsa_list_entry ==
+		    ospf_lsa_list_first(&nbr->ls_rxmt_list))
+			rxmt_timer_reset = true;
+		else
+			rxmt_timer_reset = false;
+
 		lsa->retransmit_counter--;
-		if (IS_DEBUG_OSPF(lsa, LSA_FLOODING)) /* -- endo. */
-			zlog_debug("RXmtL(%lu)--, NBR(%pI4(%s)), LSA[%s]",
-				   ospf_ls_retransmit_count(nbr),
-				   &nbr->router_id,
-				   ospf_get_name(nbr->oi->ospf),
-				   dump_lsa_key(lsa));
+		ospf_lsa_list_del(&nbr->ls_rxmt_list,
+				  ls_rxmt_node->lsa_list_entry);
+		XFREE(MTYPE_OSPF_LSA_LIST, ls_rxmt_node->lsa_list_entry);
 		ospf_lsdb_delete(&nbr->ls_rxmt, lsa);
+		if (IS_DEBUG_OSPF(lsa, LSA_FLOODING))
+			zlog_debug("RXmtL(%lu) NBR(%pI4(%s)) Delete LSA[%s]",
+				   ospf_ls_retransmit_count(nbr),
+				   &nbr->router_id, ospf_get_name(nbr->oi->ospf),
+				   dump_lsa_key(lsa));
+		ospf_lsa_unlock(&lsa);
+
+		/*
+		 * If the LS retransmission entry at the head of the list was
+		 * deleted, reset the timer.
+		 */
+		if (rxmt_timer_reset)
+			ospf_ls_retransmit_set_timer(nbr);
 	}
 }
 
 /* Clear neighbor's ls-retransmit list. */
 void ospf_ls_retransmit_clear(struct ospf_neighbor *nbr)
 {
+	struct ospf_lsa_list_entry *ls_rxmt_list_entry;
 	struct ospf_lsdb *lsdb;
 	int i;
 
@@ -1128,10 +1184,54 @@ void ospf_ls_retransmit_clear(struct ospf_neighbor *nbr)
 				ospf_ls_retransmit_delete(nbr, lsa);
 	}
 
+	frr_each_safe (ospf_lsa_list, &nbr->ls_rxmt_list, ls_rxmt_list_entry) {
+		ospf_lsa_list_del(&nbr->ls_rxmt_list, ls_rxmt_list_entry);
+		ospf_lsa_unlock(&ls_rxmt_list_entry->lsa);
+		XFREE(MTYPE_OSPF_LSA_LIST, ls_rxmt_list_entry);
+	}
+
 	ospf_lsa_unlock(&nbr->ls_req_last);
 	nbr->ls_req_last = NULL;
 }
 
+/*
+ * Set the neighbor's ls-retransmit timer based on the next
+ * LSA retransmit time.
+ */
+void ospf_ls_retransmit_set_timer(struct ospf_neighbor *nbr)
+{
+	struct ospf_lsa_list_entry *ls_rxmt_list_entry;
+
+	if (nbr->t_ls_rxmt)
+		EVENT_OFF(nbr->t_ls_rxmt);
+
+	ls_rxmt_list_entry = ospf_lsa_list_first(&nbr->ls_rxmt_list);
+	if (ls_rxmt_list_entry) {
+		struct timeval current_time, delay;
+		unsigned long delay_milliseconds;
+
+		monotime(&current_time);
+		if (timercmp(&current_time,
+			     &ls_rxmt_list_entry->list_entry_time, >=))
+			delay_milliseconds = 10;
+		else {
+			timersub(&ls_rxmt_list_entry->list_entry_time,
+				 &current_time, &delay);
+			delay_milliseconds = (delay.tv_sec * 1000) +
+					     (delay.tv_usec / 1000);
+		}
+
+		event_add_timer_msec(master, ospf_ls_rxmt_timer, nbr,
+				     delay_milliseconds, &nbr->t_ls_rxmt);
+		if (IS_DEBUG_OSPF(lsa, LSA_FLOODING))
+			zlog_debug("RXmtL(%lu) NBR(%pI4(%s)) retrans timer set in %ld msecs - Head LSA(%s)",
+				   ospf_ls_retransmit_count(nbr),
+				   &nbr->router_id, ospf_get_name(nbr->oi->ospf),
+				   delay_milliseconds,
+				   dump_lsa_key(ls_rxmt_list_entry->lsa));
+	}
+}
+
 /* Lookup LSA from neighbor's ls-retransmit list. */
 struct ospf_lsa *ospf_ls_retransmit_lookup(struct ospf_neighbor *nbr,
 					   struct ospf_lsa *lsa)
diff --git a/ospfd/ospf_flood.h b/ospfd/ospf_flood.h
index 3757400d0c..d9d9537351 100644
--- a/ospfd/ospf_flood.h
+++ b/ospfd/ospf_flood.h
@@ -7,6 +7,26 @@
 #ifndef _ZEBRA_OSPF_FLOOD_H
 #define _ZEBRA_OSPF_FLOOD_H
 
+/*
+ * OSPF Temporal LSA List
+ */
+PREDECL_DLIST(ospf_lsa_list);
+
+struct ospf_lsa_list_entry {
+	/* Linkage for LSA List */
+	struct ospf_lsa_list_item list_linkage;
+
+	/*
+	 * Time associated with the list entry. For example, for a neigbhor
+	 * link retransmission list, this is the retransmission time.
+	 */
+	struct timeval list_entry_time;
+
+	struct ospf_lsa *lsa;
+};
+
+DECLARE_DLIST(ospf_lsa_list, struct ospf_lsa_list_entry, list_linkage);
+
 extern int ospf_flood(struct ospf *, struct ospf_neighbor *, struct ospf_lsa *,
 		      struct ospf_lsa *);
 extern int ospf_flood_through(struct ospf *, struct ospf_neighbor *,
@@ -36,6 +56,8 @@ extern void ospf_ls_retransmit_add(struct ospf_neighbor *, struct ospf_lsa *);
 extern void ospf_ls_retransmit_delete(struct ospf_neighbor *,
 				      struct ospf_lsa *);
 extern void ospf_ls_retransmit_clear(struct ospf_neighbor *);
+extern void ospf_ls_retransmit_set_timer(struct ospf_neighbor *nbr);
+
 extern struct ospf_lsa *ospf_ls_retransmit_lookup(struct ospf_neighbor *,
 						  struct ospf_lsa *);
 extern void ospf_ls_retransmit_delete_nbr_area(struct ospf_area *,
diff --git a/ospfd/ospf_interface.c b/ospfd/ospf_interface.c
index 11ac7af7c9..803c36861d 100644
--- a/ospfd/ospf_interface.c
+++ b/ospfd/ospf_interface.c
@@ -542,6 +542,7 @@ static struct ospf_if_params *ospf_new_if_params(void)
 	UNSET_IF_PARAM(oip, output_cost_cmd);
 	UNSET_IF_PARAM(oip, transmit_delay);
 	UNSET_IF_PARAM(oip, retransmit_interval);
+	UNSET_IF_PARAM(oip, retransmit_window);
 	UNSET_IF_PARAM(oip, passive_interface);
 	UNSET_IF_PARAM(oip, v_hello);
 	UNSET_IF_PARAM(oip, fast_hello);
@@ -599,6 +600,7 @@ void ospf_free_if_params(struct interface *ifp, struct in_addr addr)
 	if (!OSPF_IF_PARAM_CONFIGURED(oip, output_cost_cmd) &&
 	    !OSPF_IF_PARAM_CONFIGURED(oip, transmit_delay) &&
 	    !OSPF_IF_PARAM_CONFIGURED(oip, retransmit_interval) &&
+	    !OSPF_IF_PARAM_CONFIGURED(oip, retransmit_window) &&
 	    !OSPF_IF_PARAM_CONFIGURED(oip, passive_interface) &&
 	    !OSPF_IF_PARAM_CONFIGURED(oip, v_hello) &&
 	    !OSPF_IF_PARAM_CONFIGURED(oip, fast_hello) &&
@@ -695,6 +697,9 @@ int ospf_if_new_hook(struct interface *ifp)
 	IF_DEF_PARAMS(ifp)->retransmit_interval =
 		OSPF_RETRANSMIT_INTERVAL_DEFAULT;
 
+	SET_IF_PARAM(IF_DEF_PARAMS(ifp), retransmit_window);
+	IF_DEF_PARAMS(ifp)->retransmit_window = OSPF_RETRANSMIT_WINDOW_DEFAULT;
+
 	SET_IF_PARAM(IF_DEF_PARAMS(ifp), priority);
 	IF_DEF_PARAMS(ifp)->priority = OSPF_ROUTER_PRIORITY_DEFAULT;
 
diff --git a/ospfd/ospf_interface.h b/ospfd/ospf_interface.h
index 45d0b7943a..a944847b5d 100644
--- a/ospfd/ospf_interface.h
+++ b/ospfd/ospf_interface.h
@@ -47,6 +47,8 @@ struct ospf_if_params {
 			 output_cost_cmd); /* Command Interface Output Cost */
 	DECLARE_IF_PARAM(uint32_t,
 			 retransmit_interval); /* Retransmission Interval */
+	DECLARE_IF_PARAM(uint32_t,
+			 retransmit_window); /* Retransmission Window */
 	DECLARE_IF_PARAM(uint8_t, passive_interface); /* OSPF Interface is
 							passive: no sending or
 							receiving (no need to
@@ -296,6 +298,7 @@ struct ospf_interface {
 	uint32_t ls_ack_out;   /* LS Ack message output count. */
 	uint32_t discarded;    /* discarded input count by error. */
 	uint32_t state_change; /* Number of status change. */
+	uint32_t ls_rxmt_lsa;  /* Number of LSAs retransmitted. */
 
 	uint32_t full_nbrs;
 
diff --git a/ospfd/ospf_lsdb.c b/ospfd/ospf_lsdb.c
index 0111c4924e..d1b3eb0d35 100644
--- a/ospfd/ospf_lsdb.c
+++ b/ospfd/ospf_lsdb.c
@@ -34,6 +34,59 @@ void ospf_lsdb_init(struct ospf_lsdb *lsdb)
 		lsdb->type[i].db = route_table_init();
 }
 
+static struct route_node *
+ospf_lsdb_linked_node_create(route_table_delegate_t *delegate,
+			     struct route_table *table)
+{
+	struct ospf_lsdb_linked_node *node;
+
+	node = XCALLOC(MTYPE_OSPF_LSDB_NODE,
+		       sizeof(struct ospf_lsdb_linked_node));
+
+	return (struct route_node *)node;
+}
+
+static void ospf_lsdb_linked_node_destroy(route_table_delegate_t *delegate,
+					  struct route_table *table,
+					  struct route_node *node)
+{
+	struct ospf_lsdb_linked_node *lsdb_linked_node =
+		(struct ospf_lsdb_linked_node *)node;
+
+	XFREE(MTYPE_OSPF_LSDB_NODE, lsdb_linked_node);
+}
+
+static route_table_delegate_t ospf_lsdb_linked_table_delegate = {
+	.create_node = ospf_lsdb_linked_node_create,
+	.destroy_node = ospf_lsdb_linked_node_destroy,
+};
+
+void ospf_lsdb_linked_init(struct ospf_lsdb *lsdb)
+{
+	int i;
+
+	for (i = OSPF_MIN_LSA; i < OSPF_MAX_LSA; i++)
+		lsdb->type[i].db = route_table_init_with_delegate(
+			&ospf_lsdb_linked_table_delegate);
+}
+
+struct ospf_lsdb_linked_node *ospf_lsdb_linked_lookup(struct ospf_lsdb *lsdb,
+						      struct ospf_lsa *lsa)
+{
+	struct ospf_lsdb_linked_node *lsdb_linked_node;
+	struct route_table *table;
+	struct prefix_ls lp;
+
+	table = lsdb->type[lsa->data->type].db;
+	ls_prefix_set(&lp, lsa);
+	lsdb_linked_node = (struct ospf_lsdb_linked_node *)
+		route_node_lookup(table, (struct prefix *)&lp);
+	if (lsdb_linked_node)
+		route_unlock_node((struct route_node *)lsdb_linked_node);
+
+	return lsdb_linked_node;
+}
+
 void ospf_lsdb_free(struct ospf_lsdb *lsdb)
 {
 	ospf_lsdb_cleanup(lsdb);
diff --git a/ospfd/ospf_lsdb.h b/ospfd/ospf_lsdb.h
index bf295ca830..e5e3be8baa 100644
--- a/ospfd/ospf_lsdb.h
+++ b/ospfd/ospf_lsdb.h
@@ -7,6 +7,9 @@
 #ifndef _ZEBRA_OSPF_LSDB_H
 #define _ZEBRA_OSPF_LSDB_H
 
+#include "prefix.h"
+#include "table.h"
+
 /* OSPF LSDB structure. */
 struct ospf_lsdb {
 	struct {
@@ -43,9 +46,29 @@ struct ospf_lsdb {
 #define AREA_LSDB(A,T)       ((A)->lsdb->type[(T)].db)
 #define AS_LSDB(O,T)         ((O)->lsdb->type[(T)].db)
 
+/*
+ * Alternate route node structure for LSDB nodes linked to
+ * list elements.
+ */
+struct ospf_lsdb_linked_node {
+	/*
+	 * Caution these must be the very first fields
+	 */
+	ROUTE_NODE_FIELDS
+
+	/*
+	 * List entry on an LSA list, e.g., a neighbor
+	 * retransmission list.
+	 */
+	struct ospf_lsa_list_entry *lsa_list_entry;
+};
+
 /* OSPF LSDB related functions. */
 extern struct ospf_lsdb *ospf_lsdb_new(void);
 extern void ospf_lsdb_init(struct ospf_lsdb *);
+extern void ospf_lsdb_linked_init(struct ospf_lsdb *lsdb);
+extern struct ospf_lsdb_linked_node *
+ospf_lsdb_linked_lookup(struct ospf_lsdb *lsdb, struct ospf_lsa *lsa);
 extern void ospf_lsdb_free(struct ospf_lsdb *);
 extern void ospf_lsdb_cleanup(struct ospf_lsdb *);
 extern void ls_prefix_set(struct prefix_ls *lp, struct ospf_lsa *lsa);
diff --git a/ospfd/ospf_memory.c b/ospfd/ospf_memory.c
index 9854c8cae8..478af323d3 100644
--- a/ospfd/ospf_memory.c
+++ b/ospfd/ospf_memory.c
@@ -45,3 +45,5 @@ DEFINE_MTYPE(OSPFD, OSPF_GR_HELPER, "OSPF Graceful Restart Helper");
 DEFINE_MTYPE(OSPFD, OSPF_EXTERNAL_RT_AGGR, "OSPF External Route Summarisation");
 DEFINE_MTYPE(OSPFD, OSPF_P_SPACE, "OSPF TI-LFA P-Space");
 DEFINE_MTYPE(OSPFD, OSPF_Q_SPACE, "OSPF TI-LFA Q-Space");
+DEFINE_MTYPE(OSPFD, OSPF_LSA_LIST, "OSPF LSA List");
+DEFINE_MTYPE(OSPFD, OSPF_LSDB_NODE, "OSPF LSDB Linked Node");
diff --git a/ospfd/ospf_memory.h b/ospfd/ospf_memory.h
index d11b69abb0..e2139b517b 100644
--- a/ospfd/ospf_memory.h
+++ b/ospfd/ospf_memory.h
@@ -44,5 +44,7 @@ DECLARE_MTYPE(OSPF_GR_HELPER);
 DECLARE_MTYPE(OSPF_EXTERNAL_RT_AGGR);
 DECLARE_MTYPE(OSPF_P_SPACE);
 DECLARE_MTYPE(OSPF_Q_SPACE);
+DECLARE_MTYPE(OSPF_LSA_LIST);
+DECLARE_MTYPE(OSPF_LSDB_NODE);
 
 #endif /* _QUAGGA_OSPF_MEMORY_H */
diff --git a/ospfd/ospf_neighbor.c b/ospfd/ospf_neighbor.c
index d47d581605..2514fc0ab3 100644
--- a/ospfd/ospf_neighbor.c
+++ b/ospfd/ospf_neighbor.c
@@ -68,7 +68,7 @@ struct ospf_neighbor *ospf_nbr_new(struct ospf_interface *oi)
 	nbr->v_inactivity = OSPF_IF_PARAM(oi, v_wait);
 	nbr->v_db_desc = OSPF_IF_PARAM(oi, retransmit_interval);
 	nbr->v_ls_req = OSPF_IF_PARAM(oi, retransmit_interval);
-	nbr->v_ls_upd = OSPF_IF_PARAM(oi, retransmit_interval);
+	nbr->v_ls_rxmt = OSPF_IF_PARAM(oi, retransmit_interval);
 	nbr->priority = -1;
 
 	/* DD flags. */
@@ -80,8 +80,10 @@ struct ospf_neighbor *ospf_nbr_new(struct ospf_interface *oi)
 	nbr->nbr_nbma = NULL;
 
 	ospf_lsdb_init(&nbr->db_sum);
-	ospf_lsdb_init(&nbr->ls_rxmt);
+
+	ospf_lsdb_linked_init(&nbr->ls_rxmt);
 	ospf_lsdb_init(&nbr->ls_req);
+	ospf_lsa_list_init(&nbr->ls_rxmt_list);
 
 	nbr->crypt_seqnum = 0;
 
@@ -128,7 +130,7 @@ void ospf_nbr_free(struct ospf_neighbor *nbr)
 	EVENT_OFF(nbr->t_inactivity);
 	EVENT_OFF(nbr->t_db_desc);
 	EVENT_OFF(nbr->t_ls_req);
-	EVENT_OFF(nbr->t_ls_upd);
+	EVENT_OFF(nbr->t_ls_rxmt);
 
 	/* Cancel all events. */ /* Thread lookup cost would be negligible. */
 	event_cancel_event(master, nbr);
diff --git a/ospfd/ospf_neighbor.h b/ospfd/ospf_neighbor.h
index 07d095f03d..0e041f9e6d 100644
--- a/ospfd/ospf_neighbor.h
+++ b/ospfd/ospf_neighbor.h
@@ -9,6 +9,7 @@
 
 #include <ospfd/ospf_gr.h>
 #include <ospfd/ospf_packet.h>
+#include <ospfd/ospf_flood.h>
 
 /* Neighbor Data Structure */
 struct ospf_neighbor {
@@ -44,6 +45,7 @@ struct ospf_neighbor {
 
 	/* LSA data. */
 	struct ospf_lsdb ls_rxmt;
+	struct ospf_lsa_list_head ls_rxmt_list;
 	struct ospf_lsdb db_sum;
 	struct ospf_lsdb ls_req;
 	struct ospf_lsa *ls_req_last;
@@ -54,13 +56,13 @@ struct ospf_neighbor {
 	uint32_t v_inactivity;
 	uint32_t v_db_desc;
 	uint32_t v_ls_req;
-	uint32_t v_ls_upd;
+	uint32_t v_ls_rxmt;
 
 	/* Threads. */
 	struct event *t_inactivity;
 	struct event *t_db_desc;
 	struct event *t_ls_req;
-	struct event *t_ls_upd;
+	struct event *t_ls_rxmt;
 	struct event *t_hello_reply;
 
 	/* NBMA configured neighbour */
@@ -71,6 +73,7 @@ struct ospf_neighbor {
 	struct timeval ts_last_regress;  /* last regressive NSM change     */
 	const char *last_regress_str;    /* Event which last regressed NSM */
 	uint32_t state_change;		 /* NSM state change counter       */
+	uint32_t ls_rxmt_lsa;		 /* Number of LSAs retransmited.   */
 
 	/* BFD information */
 	struct bfd_session_params *bfd_session;
diff --git a/ospfd/ospf_nsm.c b/ospfd/ospf_nsm.c
index c466ddcc6f..079a1fa55e 100644
--- a/ospfd/ospf_nsm.c
+++ b/ospfd/ospf_nsm.c
@@ -112,18 +112,16 @@ static void nsm_timer_set(struct ospf_neighbor *nbr)
 	case NSM_Init:
 	case NSM_TwoWay:
 		EVENT_OFF(nbr->t_db_desc);
-		EVENT_OFF(nbr->t_ls_upd);
+		EVENT_OFF(nbr->t_ls_rxmt);
 		EVENT_OFF(nbr->t_ls_req);
 		break;
 	case NSM_ExStart:
 		OSPF_NSM_TIMER_ON(nbr->t_db_desc, ospf_db_desc_timer,
 				  nbr->v_db_desc);
-		EVENT_OFF(nbr->t_ls_upd);
+		EVENT_OFF(nbr->t_ls_rxmt);
 		EVENT_OFF(nbr->t_ls_req);
 		break;
 	case NSM_Exchange:
-		OSPF_NSM_TIMER_ON(nbr->t_ls_upd, ospf_ls_upd_timer,
-				  nbr->v_ls_upd);
 		if (!IS_SET_DD_MS(nbr->dd_flags))
 			EVENT_OFF(nbr->t_db_desc);
 		break;
diff --git a/ospfd/ospf_packet.c b/ospfd/ospf_packet.c
index 87aaccad92..86f877b621 100644
--- a/ospfd/ospf_packet.c
+++ b/ospfd/ospf_packet.c
@@ -292,54 +292,66 @@ void ospf_ls_req_event(struct ospf_neighbor *nbr)
 	event_add_event(master, ospf_ls_req_timer, nbr, 0, &nbr->t_ls_req);
 }
 
-/* Cyclic timer function.  Fist registered in ospf_nbr_new () in
-   ospf_neighbor.c  */
-void ospf_ls_upd_timer(struct event *thread)
+/*
+ * OSPF neighbor link state retransmission timer handler. Unicast
+ * unacknowledged LSAs to the neigbhors.
+ */
+void ospf_ls_rxmt_timer(struct event *thread)
 {
 	struct ospf_neighbor *nbr;
+	int retransmit_interval, retransmit_window, rxmt_lsa_count = 0;
 
 	nbr = EVENT_ARG(thread);
-	nbr->t_ls_upd = NULL;
+	nbr->t_ls_rxmt = NULL;
+	retransmit_interval = nbr->v_ls_rxmt;
+	retransmit_window = OSPF_IF_PARAM(nbr->oi, retransmit_window);
 
 	/* Send Link State Update. */
 	if (ospf_ls_retransmit_count(nbr) > 0) {
+		struct ospf_lsa_list_entry *ls_rxmt_list_entry;
+		struct timeval current_time, latest_rxmt_time, next_rxmt_time;
+		struct timeval rxmt_interval = { retransmit_interval, 0 };
+		struct timeval rxmt_window;
 		struct list *update;
-		struct ospf_lsdb *lsdb;
-		int i;
-		int retransmit_interval;
 
-		retransmit_interval =
-			OSPF_IF_PARAM(nbr->oi, retransmit_interval);
+		/*
+		 * Set the retransmission window based on the configured value
+		 * in milliseconds.
+		 */
+		rxmt_window.tv_sec = retransmit_window / 1000;
+		rxmt_window.tv_usec = (retransmit_window % 1000) * 1000;
+
+		/*
+		 * Calculate the latest retransmit time for LSAs transmited in
+		 * this timer pass by adding the retransmission window to the
+		 * current time. Calculate the next retransmission time by adding
+		 * the retransmit interval to the current time.
+		 */
+		monotime(&current_time);
+		timeradd(&current_time, &rxmt_window, &latest_rxmt_time);
+		timeradd(&current_time, &rxmt_interval, &next_rxmt_time);
 
-		lsdb = &nbr->ls_rxmt;
 		update = list_new();
+		while ((ls_rxmt_list_entry =
+				ospf_lsa_list_first(&nbr->ls_rxmt_list))) {
+			if (timercmp(&ls_rxmt_list_entry->list_entry_time,
+				     &latest_rxmt_time, >))
+				break;
 
-		for (i = OSPF_MIN_LSA; i < OSPF_MAX_LSA; i++) {
-			struct route_table *table = lsdb->type[i].db;
-			struct route_node *rn;
+			listnode_add(update, ls_rxmt_list_entry->lsa);
+			rxmt_lsa_count++;
 
-			for (rn = route_top(table); rn; rn = route_next(rn)) {
-				struct ospf_lsa *lsa;
-
-				if ((lsa = rn->info) != NULL) {
-					/* Don't retransmit an LSA if we
-					  received it within
-					  the last RxmtInterval seconds - this
-					  is to allow the
-					  neighbour a chance to acknowledge the
-					  LSA as it may
-					  have ben just received before the
-					  retransmit timer
-					  fired.  This is a small tweak to what
-					  is in the RFC,
-					  but it will cut out out a lot of
-					  retransmit traffic
-					  - MAG */
-					if (monotime_since(&lsa->tv_recv, NULL)
-					    >= retransmit_interval * 1000000LL)
-						listnode_add(update, rn->info);
-				}
-			}
+			/*
+			 * Set the next retransmit time for the LSA and move it
+			 * to the end of the neighbor's retransmission list.
+			 */
+			ls_rxmt_list_entry->list_entry_time = next_rxmt_time;
+			ospf_lsa_list_del(&nbr->ls_rxmt_list,
+					  ls_rxmt_list_entry);
+			ospf_lsa_list_add_tail(&nbr->ls_rxmt_list,
+					       ls_rxmt_list_entry);
+			nbr->ls_rxmt_lsa++;
+			nbr->oi->ls_rxmt_lsa++;
 		}
 
 		if (listcount(update) > 0)
@@ -348,8 +360,13 @@ void ospf_ls_upd_timer(struct event *thread)
 		list_delete(&update);
 	}
 
+	if (IS_DEBUG_OSPF_EVENT)
+		zlog_debug("RXmtL(%lu) NBR(%pI4(%s)) timer event - sent %u LSAs",
+			   ospf_ls_retransmit_count(nbr), &nbr->router_id,
+			   ospf_get_name(nbr->oi->ospf), rxmt_lsa_count);
+
 	/* Set LS Update retransmission timer. */
-	OSPF_NSM_TIMER_ON(nbr->t_ls_upd, ospf_ls_upd_timer, nbr->v_ls_upd);
+	ospf_ls_retransmit_set_timer(nbr);
 }
 
 void ospf_ls_ack_timer(struct event *thread)
diff --git a/ospfd/ospf_packet.h b/ospfd/ospf_packet.h
index 234738979e..2c9dba6c88 100644
--- a/ospfd/ospf_packet.h
+++ b/ospfd/ospf_packet.h
@@ -140,7 +140,7 @@ extern void ospf_ls_ack_send_delayed(struct ospf_interface *);
 extern void ospf_ls_retransmit(struct ospf_interface *, struct ospf_lsa *);
 extern void ospf_ls_req_event(struct ospf_neighbor *);
 
-extern void ospf_ls_upd_timer(struct event *thread);
+extern void ospf_ls_rxmt_timer(struct event *thread);
 extern void ospf_ls_ack_timer(struct event *thread);
 extern void ospf_poll_timer(struct event *thread);
 extern void ospf_hello_reply_timer(struct event *thread);
diff --git a/ospfd/ospf_vty.c b/ospfd/ospf_vty.c
index 3a11b21232..7a7a684dd6 100644
--- a/ospfd/ospf_vty.c
+++ b/ospfd/ospf_vty.c
@@ -815,6 +815,7 @@ struct ospf_vl_config_data {
 	int del_keychain;
 	int hello_interval;     /* Obvious what these are... */
 	int retransmit_interval;
+	int retransmit_window;
 	int transmit_delay;
 	int dead_interval;
 };
@@ -957,6 +958,12 @@ static int ospf_vl_set_timers(struct ospf_vl_data *vl_data,
 			vl_config->retransmit_interval;
 	}
 
+	if (vl_config->retransmit_window) {
+		SET_IF_PARAM(IF_DEF_PARAMS(ifp), retransmit_window);
+		IF_DEF_PARAMS(ifp)->retransmit_window =
+			vl_config->retransmit_window;
+	}
+
 	if (vl_config->transmit_delay) {
 		SET_IF_PARAM(IF_DEF_PARAMS(ifp), transmit_delay);
 		IF_DEF_PARAMS(ifp)->transmit_delay = vl_config->transmit_delay;
@@ -1012,14 +1019,16 @@ static int ospf_vl_set(struct ospf *ospf, struct ospf_vl_config_data *vl_config)
 	"Use null authentication\n"                                            \
 	"Use message-digest authentication\n"
 
-#define VLINK_HELPSTR_TIME_PARAM                                               \
-	"Time between HELLO packets\n"                                         \
-	"Seconds\n"                                                            \
-	"Time between retransmitting lost link state advertisements\n"         \
-	"Seconds\n"                                                            \
-	"Link state transmit delay\n"                                          \
-	"Seconds\n"                                                            \
-	"Interval time after which a neighbor is declared down\n"              \
+#define VLINK_HELPSTR_TIME_PARAM                                                \
+	"Time between HELLO packets\n"                                          \
+	"Seconds\n"                                                             \
+	"Time between retransmitting lost link state advertisements\n"          \
+	"Seconds\n"                                                             \
+	"Window for LSA retransmit - Retransmit LSAs expiring in this window\n" \
+	"Milliseconds\n"                                                        \
+	"Link state transmit delay\n"                                           \
+	"Seconds\n"                                                             \
+	"Interval time after which a neighbor is declared down\n"               \
 	"Seconds\n"
 
 #define VLINK_HELPSTR_AUTH_SIMPLE                                              \
@@ -1204,7 +1213,7 @@ DEFUN (no_ospf_area_vlink,
 
 DEFUN (ospf_area_vlink_intervals,
        ospf_area_vlink_intervals_cmd,
-       "area <A.B.C.D|(0-4294967295)> virtual-link A.B.C.D {hello-interval (1-65535)|retransmit-interval (1-65535)|transmit-delay (1-65535)|dead-interval (1-65535)}",
+       "area <A.B.C.D|(0-4294967295)> virtual-link A.B.C.D {hello-interval (1-65535)|retransmit-interval (1-65535)|retransmit-window (20-10000)|transmit-delay (1-65535)|dead-interval (1-65535)}",
        VLINK_HELPSTR_IPADDR
        VLINK_HELPSTR_TIME_PARAM)
 {
@@ -1236,6 +1245,9 @@ DEFUN (ospf_area_vlink_intervals,
 		else if (strmatch(argv[idx]->text, "retransmit-interval"))
 			vl_config.retransmit_interval =
 				strtol(argv[++idx]->arg, NULL, 10);
+		else if (strmatch(argv[idx]->text, "retransmit-window"))
+			vl_config.retransmit_window = strtol(argv[++idx]->arg,
+							     NULL, 10);
 		else if (strmatch(argv[idx]->text, "transmit-delay"))
 			vl_config.transmit_delay =
 				strtol(argv[++idx]->arg, NULL, 10);
@@ -1250,7 +1262,7 @@ DEFUN (ospf_area_vlink_intervals,
 
 DEFUN (no_ospf_area_vlink_intervals,
        no_ospf_area_vlink_intervals_cmd,
-       "no area <A.B.C.D|(0-4294967295)> virtual-link A.B.C.D {hello-interval (1-65535)|retransmit-interval (1-65535)|transmit-delay (1-65535)|dead-interval (1-65535)}",
+       "no area <A.B.C.D|(0-4294967295)> virtual-link A.B.C.D {hello-interval (1-65535)|retransmit-interval (1-65535)|retransmit-window (20-1000)|transmit-delay (1-65535)|dead-interval (1-65535)}",
        NO_STR
        VLINK_HELPSTR_IPADDR
        VLINK_HELPSTR_TIME_PARAM)
@@ -1282,6 +1294,9 @@ DEFUN (no_ospf_area_vlink_intervals,
 		else if (strmatch(argv[idx]->text, "retransmit-interval"))
 			vl_config.retransmit_interval =
 				OSPF_RETRANSMIT_INTERVAL_DEFAULT;
+		else if (strmatch(argv[idx]->text, "retransmit-window"))
+			vl_config.retransmit_window =
+				OSPF_RETRANSMIT_WINDOW_DEFAULT;
 		else if (strmatch(argv[idx]->text, "transmit-delay"))
 			vl_config.transmit_delay = OSPF_TRANSMIT_DELAY_DEFAULT;
 		else if (strmatch(argv[idx]->text, "dead-interval"))
@@ -3846,6 +3861,10 @@ static void show_ip_ospf_interface_sub(struct vty *vty, struct ospf *ospf,
 			json_object_int_add(
 				json_interface_sub, "timerRetransmitSecs",
 				OSPF_IF_PARAM(oi, retransmit_interval));
+			json_object_int_add(json_interface_sub,
+					    "timerRetransmitWindowMsecs",
+					    OSPF_IF_PARAM(oi,
+							  retransmit_window));
 		} else {
 			vty_out(vty, "  Timer intervals configured,");
 			vty_out(vty, " Hello ");
@@ -3964,6 +3983,16 @@ static void show_ip_ospf_interface_sub(struct vty *vty, struct ospf *ospf,
 						       "nbrFilterPrefixList",
 						       "N/A");
 		}
+
+		/* Non-Traffic interface counters
+		 */
+		if (use_json)
+			json_object_int_add(json_interface_sub,
+					    "lsaRetransmissions",
+					    oi->ls_rxmt_lsa);
+		else
+			vty_out(vty, "  LSA retransmissions: %u\n",
+				oi->ls_rxmt_lsa);
 	}
 }
 
@@ -5177,12 +5206,20 @@ static void show_ip_ospf_neighbor_detail_sub(struct vty *vty,
 			lookup_msg(ospf_ism_state_msg, ospf_nbr_ism_state(nbr),
 				   NULL));
 	}
+
 	/* Show state changes. */
 	if (use_json)
 		json_object_int_add(json_neigh, "stateChangeCounter",
 				    nbr->state_change);
 	else
-		vty_out(vty, " %d state changes\n", nbr->state_change);
+		vty_out(vty, "    %d state changes\n", nbr->state_change);
+
+	/* Show LSA retransmissions. */
+	if (use_json)
+		json_object_int_add(json_neigh, "lsaRetransmissions",
+				    nbr->ls_rxmt_lsa);
+	else
+		vty_out(vty, "    %u LSA retransmissions\n", nbr->ls_rxmt_lsa);
 
 	if (nbr->ts_last_progress.tv_sec || nbr->ts_last_progress.tv_usec) {
 		struct timeval res;
@@ -5231,7 +5268,7 @@ static void show_ip_ospf_neighbor_detail_sub(struct vty *vty,
 	if (DR(oi).s_addr == INADDR_ANY) {
 		if (!use_json)
 			vty_out(vty,
-				"  No designated router on this network\n");
+				"    No designated router on this network\n");
 	} else {
 		nbr_dr = ospf_nbr_lookup_by_addr(oi->nbrs, &DR(oi));
 		if (nbr_dr) {
@@ -5250,14 +5287,14 @@ static void show_ip_ospf_neighbor_detail_sub(struct vty *vty,
 	if (nbr_bdr == NULL) {
 		if (!use_json)
 			vty_out(vty,
-				"  No backup designated router on this network\n");
+				"    No backup designated router on this network\n");
 	} else {
 		if (use_json)
 			json_object_string_addf(json_neigh,
 						"routerDesignatedBackupId",
 						"%pI4", &nbr_bdr->router_id);
 		else
-			vty_out(vty, " BDR is %pI4\n", &nbr_bdr->router_id);
+			vty_out(vty, "     BDR is %pI4\n", &nbr_bdr->router_id);
 	}
 
 	/* Show options. */
@@ -5347,7 +5384,7 @@ static void show_ip_ospf_neighbor_detail_sub(struct vty *vty,
 
 	/* Show Link State Update Retransmission thread. */
 	if (use_json) {
-		if (nbr->t_ls_upd != NULL)
+		if (nbr->t_ls_rxmt != NULL)
 			json_object_string_add(
 				json_neigh,
 				"threadLinkStateUpdateRetransmission",
@@ -5355,7 +5392,7 @@ static void show_ip_ospf_neighbor_detail_sub(struct vty *vty,
 	} else
 		vty_out(vty,
 			"    Thread Link State Update Retransmission %s\n\n",
-			nbr->t_ls_upd != NULL ? "on" : "off");
+			nbr->t_ls_rxmt != NULL ? "on" : "off");
 
 	if (!use_json) {
 		vty_out(vty, "    Graceful restart Helper info:\n");
@@ -7993,7 +8030,7 @@ static void ospf_nbr_timer_update(struct ospf_interface *oi)
 		nbr->v_inactivity = OSPF_IF_PARAM(oi, v_wait);
 		nbr->v_db_desc = OSPF_IF_PARAM(oi, retransmit_interval);
 		nbr->v_ls_req = OSPF_IF_PARAM(oi, retransmit_interval);
-		nbr->v_ls_upd = OSPF_IF_PARAM(oi, retransmit_interval);
+		nbr->v_ls_rxmt = OSPF_IF_PARAM(oi, retransmit_interval);
 	}
 }
 
@@ -8728,6 +8765,40 @@ DEFUN_HIDDEN (no_ospf_retransmit_interval,
 	return no_ip_ospf_retransmit_interval(self, vty, argc, argv);
 }
 
+DEFPY(ip_ospf_retransmit_window, ip_ospf_retransmit_window_addr_cmd,
+      "[no] ip ospf retransmit-window ![(20-1000)]$retransmit-window [A.B.C.D]$ip_addr", NO_STR
+      "IP Information\n"
+      "OSPF interface commands\n"
+      "Window for LSA retransmit - Retransmit LSAs expiring in this window\n"
+      "Milliseconds\n"
+      "Address of interface\n")
+{
+	VTY_DECLVAR_CONTEXT(interface, ifp);
+	struct ospf_if_params *params;
+
+	params = IF_DEF_PARAMS(ifp);
+
+	if (ip_addr.s_addr != INADDR_ANY) {
+		params = ospf_get_if_params(ifp, ip_addr);
+		ospf_if_update_params(ifp, ip_addr);
+	}
+
+	if (no) {
+		UNSET_IF_PARAM(params, retransmit_window);
+		params->retransmit_window = OSPF_RETRANSMIT_WINDOW_DEFAULT;
+	} else {
+		SET_IF_PARAM(params, retransmit_window);
+		params->retransmit_window = retransmit_window;
+	}
+
+	/*
+	 * There is nothing to do when the retransmit-window changes, any
+	 * change will take effect the next time the interface LSA retransmision
+	 * timer expires.
+	 */
+	return CMD_SUCCESS;
+}
+
 DEFPY (ip_ospf_gr_hdelay,
        ip_ospf_gr_hdelay_cmd,
        "ip ospf graceful-restart hello-delay (1-1800)",
@@ -12210,6 +12281,17 @@ static int config_write_interface_one(struct vty *vty, struct vrf *vrf)
 				vty_out(vty, "\n");
 			}
 
+			/* Retransmit Window print. */
+			if (OSPF_IF_PARAM_CONFIGURED(params, retransmit_window) &&
+			    params->retransmit_window !=
+				    OSPF_RETRANSMIT_WINDOW_DEFAULT) {
+				vty_out(vty, " ip ospf retransmit-window %u",
+					params->retransmit_window);
+				if (params != IF_DEF_PARAMS(ifp) && rn)
+					vty_out(vty, " %pI4", &rn->p.u.prefix4);
+				vty_out(vty, "\n");
+			}
+
 			/* Transmit Delay print. */
 			if (OSPF_IF_PARAM_CONFIGURED(params, transmit_delay)
 			    && params->transmit_delay
@@ -12567,19 +12649,22 @@ static int config_write_virtual_link(struct vty *vty, struct ospf *ospf)
 			oi = vl_data->vl_oi;
 
 			/* timers */
-			if (OSPF_IF_PARAM(oi, v_hello)
-				    != OSPF_HELLO_INTERVAL_DEFAULT
-			    || OSPF_IF_PARAM(oi, v_wait)
-				       != OSPF_ROUTER_DEAD_INTERVAL_DEFAULT
-			    || OSPF_IF_PARAM(oi, retransmit_interval)
-				       != OSPF_RETRANSMIT_INTERVAL_DEFAULT
-			    || OSPF_IF_PARAM(oi, transmit_delay)
-				       != OSPF_TRANSMIT_DELAY_DEFAULT)
+			if (OSPF_IF_PARAM(oi, v_hello) !=
+				    OSPF_HELLO_INTERVAL_DEFAULT ||
+			    OSPF_IF_PARAM(oi, v_wait) !=
+				    OSPF_ROUTER_DEAD_INTERVAL_DEFAULT ||
+			    OSPF_IF_PARAM(oi, retransmit_interval) !=
+				    OSPF_RETRANSMIT_INTERVAL_DEFAULT ||
+			    OSPF_IF_PARAM(oi, retransmit_window) !=
+				    OSPF_RETRANSMIT_WINDOW_DEFAULT ||
+			    OSPF_IF_PARAM(oi, transmit_delay) !=
+				    OSPF_TRANSMIT_DELAY_DEFAULT)
 				vty_out(vty,
-					" area %s virtual-link %pI4 hello-interval %d retransmit-interval %d transmit-delay %d dead-interval %d\n",
+					" area %s virtual-link %pI4 hello-interval %d retransmit-interval %d retransmit-window %d transmit-delay %d dead-interval %d\n",
 					buf, &vl_data->vl_peer,
 					OSPF_IF_PARAM(oi, v_hello),
 					OSPF_IF_PARAM(oi, retransmit_interval),
+					OSPF_IF_PARAM(oi, retransmit_window),
 					OSPF_IF_PARAM(oi, transmit_delay),
 					OSPF_IF_PARAM(oi, v_wait));
 			else
@@ -13112,6 +13197,9 @@ static void ospf_vty_if_init(void)
 	install_element(INTERFACE_NODE,
 			&no_ip_ospf_retransmit_interval_addr_cmd);
 
+	/* "ip ospf retransmit-window" commands. */
+	install_element(INTERFACE_NODE, &ip_ospf_retransmit_window_addr_cmd);
+
 	/* "ip ospf transmit-delay" commands. */
 	install_element(INTERFACE_NODE, &ip_ospf_transmit_delay_addr_cmd);
 	install_element(INTERFACE_NODE, &no_ip_ospf_transmit_delay_addr_cmd);
diff --git a/tests/topotests/all_protocol_startup/r1/show_ip_ospf_interface.ref b/tests/topotests/all_protocol_startup/r1/show_ip_ospf_interface.ref
index f52b51d9d8..e4e3290111 100644
--- a/tests/topotests/all_protocol_startup/r1/show_ip_ospf_interface.ref
+++ b/tests/topotests/all_protocol_startup/r1/show_ip_ospf_interface.ref
@@ -11,6 +11,7 @@ r1-eth0 is up
     Hello due in XX.XXXs
   Neighbor Count is 0, Adjacent neighbor count is 0
   Graceful Restart hello delay: 10s
+  LSA retransmissions: 0
 r1-eth3 is up
   ifindex X, MTU 1500 bytes, BW XX Mbit <UP,LOWER_UP,BROADCAST,RUNNING,MULTICAST>
   Internet Address 192.168.3.1/26, Broadcast 192.168.3.63, Area 0.0.0.0
@@ -24,3 +25,4 @@ r1-eth3 is up
     Hello due in XX.XXXs
   Neighbor Count is 0, Adjacent neighbor count is 0
   Graceful Restart hello delay: 10s
+  LSA retransmissions: 0
diff --git a/tests/topotests/ospf_p2mp/r1/frr-p2mp.conf b/tests/topotests/ospf_p2mp/r1/frr-p2mp.conf
index cb4538c0e3..89f255bb44 100644
--- a/tests/topotests/ospf_p2mp/r1/frr-p2mp.conf
+++ b/tests/topotests/ospf_p2mp/r1/frr-p2mp.conf
@@ -1,4 +1,10 @@
 !
+!log file ospfd.log debug
+! debug ospf event
+! debug ospf client
+! debug ospf lsa
+! debug ospf packet all
+
 hostname r1
 password zebra
 log file /tmp/r1-frr.log
diff --git a/tests/topotests/ospf_p2mp/r2/frr-p2mp.conf b/tests/topotests/ospf_p2mp/r2/frr-p2mp.conf
index 0ca8aec3bf..429330987e 100644
--- a/tests/topotests/ospf_p2mp/r2/frr-p2mp.conf
+++ b/tests/topotests/ospf_p2mp/r2/frr-p2mp.conf
@@ -1,4 +1,10 @@
 !
+!log file ospfd.log debug
+! debug ospf event
+! debug ospf client
+! debug ospf lsa
+! debug ospf packet all
+!
 hostname r2
 password zebra
 log file /tmp/r1-frr.log
diff --git a/tests/topotests/ospf_p2mp/r3/frr-p2mp.conf b/tests/topotests/ospf_p2mp/r3/frr-p2mp.conf
index 41ea70d443..eada78450e 100644
--- a/tests/topotests/ospf_p2mp/r3/frr-p2mp.conf
+++ b/tests/topotests/ospf_p2mp/r3/frr-p2mp.conf
@@ -1,4 +1,10 @@
 !
+!log file ospfd.log debug
+! debug ospf event
+! debug ospf client
+! debug ospf lsa
+! debug ospf packet all
+!
 hostname r3
 password zebra
 log file /tmp/r1-frr.log
diff --git a/tests/topotests/ospf_p2mp/r4/frr-p2mp.conf b/tests/topotests/ospf_p2mp/r4/frr-p2mp.conf
index 21fa9c72f9..3146ea0957 100644
--- a/tests/topotests/ospf_p2mp/r4/frr-p2mp.conf
+++ b/tests/topotests/ospf_p2mp/r4/frr-p2mp.conf
@@ -1,4 +1,10 @@
 !
+!log file ospfd.log debug
+! debug ospf event
+! debug ospf client
+! debug ospf lsa
+! debug ospf packet all
+!
 hostname r4
 password zebra
 log file /tmp/r1-frr.log
diff --git a/tests/topotests/ospf_p2mp/test_ospf_p2mp_broadcast.py b/tests/topotests/ospf_p2mp/test_ospf_p2mp_broadcast.py
index d52c8147fe..455c737f0d 100644
--- a/tests/topotests/ospf_p2mp/test_ospf_p2mp_broadcast.py
+++ b/tests/topotests/ospf_p2mp/test_ospf_p2mp_broadcast.py
@@ -9,6 +9,7 @@
 
 import os
 import sys
+from time import sleep
 from functools import partial
 import pytest
 
@@ -113,7 +114,9 @@ def teardown_module():
     tgen.stop_topology()
 
 
-def verify_p2mp_interface(tgen, router, nbr_cnt, nbr_adj_cnt, nbr_filter):
+def verify_p2mp_interface(
+    tgen, router, nbr_cnt, nbr_adj_cnt, delay_reflood, nbr_filter
+):
     "Verify the P2MP Configuration and interface settings"
 
     topo_router = tgen.gears[router]
@@ -147,7 +150,7 @@ def verify_p2mp_interface(tgen, router, nbr_cnt, nbr_adj_cnt, nbr_filter):
                 "nbrCount": nbr_cnt,
                 "nbrAdjacentCount": nbr_adj_cnt,
                 "prefixSuppression": False,
-                "p2mpDelayReflood": False,
+                "p2mpDelayReflood": delay_reflood,
                 "nbrFilterPrefixList": nbr_filter,
             }
         }
@@ -280,7 +283,7 @@ def test_p2mp_broadcast_interface():
         pytest.skip("Skipped because of router(s) failure")
 
     step("Verify router r1 interface r1-eth0 p2mp configuration")
-    verify_p2mp_interface(tgen, "r1", 3, 3, "N/A")
+    verify_p2mp_interface(tgen, "r1", 3, 3, False, "N/A")
 
     step("Verify router r1 p2mp interface r1-eth0 neighbors")
     verify_p2mp_neighbor(
@@ -305,7 +308,7 @@ def test_p2mp_broadcast_interface():
 
     step("Verify router r1 interface r1-eth0 p2mp configuration application")
     r1.vtysh_cmd("conf t\ninterface r1-eth0\nip ospf network point-to-multipoint")
-    verify_p2mp_interface(tgen, "r1", 3, 3, "N/A")
+    verify_p2mp_interface(tgen, "r1", 3, 3, False, "N/A")
 
     step("Verify restablishment of r1-eth0 p2mp neighbors")
     verify_p2mp_neighbor(
@@ -324,14 +327,14 @@ def test_p2mp_broadcast_interface():
     verify_p2mp_route(tgen, "r1", "10.1.4.0/24", 24, "10.1.0.4", "r1-eth0")
 
 
-def test_p2mp_broadcast_neighbor_filter():
+def p2mp_broadcast_neighbor_filter_common(delay_reflood):
     tgen = get_topogen()
 
     if tgen.routers_have_failure():
         pytest.skip("Skipped because of router(s) failure")
 
     step("Verify router r1 interface r1-eth0 p2mp configuration")
-    verify_p2mp_interface(tgen, "r1", 3, 3, "N/A")
+    verify_p2mp_interface(tgen, "r1", 3, 3, delay_reflood, "N/A")
 
     step("Verify router r1 p2mp interface r1-eth0 neighbors")
     verify_p2mp_neighbor(
@@ -362,7 +365,7 @@ def test_p2mp_broadcast_neighbor_filter():
     assert neighbor_filter_cfg == " ip ospf neighbor-filter nbr-filter", assertmsg
 
     step("Verify non-existent neighbor-filter is not applied to r1 interfaces")
-    verify_p2mp_interface(tgen, "r1", 3, 3, "N/A")
+    verify_p2mp_interface(tgen, "r1", 3, 3, delay_reflood, "N/A")
 
     step("Add nbr-filter prefix-list configuration to r1")
     r1.vtysh_cmd("conf t\nip prefix-list nbr-filter seq 200 permit any")
@@ -370,7 +373,7 @@ def test_p2mp_broadcast_neighbor_filter():
     step(
         "Verify neighbor-filter is now applied to r1 interface and neighbors still adjacent"
     )
-    verify_p2mp_interface(tgen, "r1", 3, 3, "nbr-filter")
+    verify_p2mp_interface(tgen, "r1", 3, 3, delay_reflood, "nbr-filter")
 
     step("Add nbr-filter prefix-list configuration to block r4")
     r1.vtysh_cmd("conf t\nip prefix-list nbr-filter seq 10 deny 10.1.0.4/32")
@@ -378,7 +381,7 @@ def test_p2mp_broadcast_neighbor_filter():
     step(
         "Verify neighbor-filter is now applied to r1 interface and r4 is no longer adjacent"
     )
-    verify_p2mp_interface(tgen, "r1", 2, 2, "nbr-filter")
+    verify_p2mp_interface(tgen, "r1", 2, 2, delay_reflood, "nbr-filter")
     verify_p2mp_neighbor_missing(tgen, "r1", "4.4.4.4")
 
     step("Verify route to r4 subnet is now through r2")
@@ -390,7 +393,7 @@ def test_p2mp_broadcast_neighbor_filter():
     step(
         "Verify neighbor-filter is now applied to r1 interface and r2 is no longer adjacent"
     )
-    verify_p2mp_interface(tgen, "r1", 1, 1, "nbr-filter")
+    verify_p2mp_interface(tgen, "r1", 1, 1, delay_reflood, "nbr-filter")
     verify_p2mp_neighbor_missing(tgen, "r1", "2.2.2.2")
 
     step("Verify route to r4 and r2 subnet are now through r3")
@@ -406,24 +409,105 @@ def test_p2mp_broadcast_neighbor_filter():
     assert rc, assertmsg
 
     step("Verify interface neighbor-filter is removed and neighbors present")
-    verify_p2mp_interface(tgen, "r1", 3, 3, "N/A")
+    verify_p2mp_interface(tgen, "r1", 3, 3, delay_reflood, "N/A")
 
     step("Add neighbor filter configuration and verify neighbors are filtered")
     r1.vtysh_cmd("conf t\ninterface r1-eth0\nip ospf neighbor-filter nbr-filter")
-    verify_p2mp_interface(tgen, "r1", 1, 1, "nbr-filter")
+    verify_p2mp_interface(tgen, "r1", 1, 1, delay_reflood, "nbr-filter")
     verify_p2mp_neighbor_missing(tgen, "r1", "2.2.2.2")
     verify_p2mp_neighbor_missing(tgen, "r1", "4.4.4.4")
 
     step("Remove nbr-filter prefix-list configuration to block r2 and verify neighbor")
     r1.vtysh_cmd("conf t\nno ip prefix-list nbr-filter seq 20")
-    verify_p2mp_interface(tgen, "r1", 2, 2, "nbr-filter")
+    verify_p2mp_interface(tgen, "r1", 2, 2, delay_reflood, "nbr-filter")
     verify_p2mp_neighbor(
         tgen, "r1", "2.2.2.2", "Full/DROther", "10.1.0.2", "r1-eth0:10.1.0.1"
     )
 
     step("Delete nbr-filter prefix-list and verify neighbors are present")
     r1.vtysh_cmd("conf t\nno ip prefix-list nbr-filter")
-    verify_p2mp_interface(tgen, "r1", 3, 3, "N/A")
+    verify_p2mp_interface(tgen, "r1", 3, 3, delay_reflood, "N/A")
+
+
+def test_p2mp_broadcast_neighbor_filter():
+    p2mp_broadcast_neighbor_filter_common(False)
+
+
+def test_p2mp_broadcast_neighbor_filter_delay_reflood():
+    tgen = get_topogen()
+
+    if tgen.routers_have_failure():
+        pytest.skip("Skipped because of router(s) failure")
+
+    step("Modify router r1 interface r1-eth0 p2mp delay-reflood configuration")
+    r1 = tgen.gears["r1"]
+    r1.vtysh_cmd(
+        "conf t\ninterface r1-eth0\nip ospf network point-to-multipoint delay-reflood"
+    )
+    verify_p2mp_interface(tgen, "r1", 3, 3, True, "N/A")
+
+    step("Modify router r2 interface r2-eth0 p2mp delay-reflood configuration")
+    r2 = tgen.gears["r2"]
+    r2.vtysh_cmd(
+        "conf t\ninterface r2-eth0\nip ospf network point-to-multipoint delay-reflood"
+    )
+
+    step("Modify router r3 interface r3-eth0 p2mp delay-reflood configuration")
+    r3 = tgen.gears["r3"]
+    r3.vtysh_cmd(
+        "conf t\ninterface r3-eth0\nip ospf network point-to-multipoint delay-reflood"
+    )
+
+    step("Modify router r4 interface r4-eth0 p2mp delay-reflood configuration")
+    r4 = tgen.gears["r4"]
+    r4.vtysh_cmd(
+        "conf t\ninterface r4-eth0\nip ospf network point-to-multipoint delay-reflood"
+    )
+
+    p2mp_broadcast_neighbor_filter_common(True)
+
+    step("Recreate a partial P2MP mesh with neighbor filters")
+    step("Add nbr-filter prefix-list configuration to block r4")
+    r1.vtysh_cmd("conf t\nip prefix-list nbr-filter seq 30 permit any")
+    r1.vtysh_cmd("conf t\nip prefix-list nbr-filter seq 10 deny 10.1.0.3/32")
+    r1.vtysh_cmd("conf t\nip prefix-list nbr-filter seq 20 deny 10.1.0.4/32")
+    r1.vtysh_cmd("conf t\ninterface r1-eth0\nip ospf neighbor-filter nbr-filter")
+
+    r2.vtysh_cmd("conf t\nip prefix-list nbr-filter seq 30 permit any")
+    r2.vtysh_cmd("conf t\nip prefix-list nbr-filter seq 10 deny 10.1.0.4/32")
+    r2.vtysh_cmd("conf t\ninterface r2-eth0\nip ospf neighbor-filter nbr-filter")
+
+    r3.vtysh_cmd("conf t\nip prefix-list nbr-filter seq 30 permit any")
+    r3.vtysh_cmd("conf t\nip prefix-list nbr-filter seq 10 deny 10.1.0.1/32")
+    r3.vtysh_cmd("conf t\ninterface r3-eth0\nip ospf neighbor-filter nbr-filter")
+
+    r4.vtysh_cmd("conf t\nip prefix-list nbr-filter seq 30 permit any")
+    r4.vtysh_cmd("conf t\nip prefix-list nbr-filter seq 10 deny 10.1.0.1/32")
+    r4.vtysh_cmd("conf t\nip prefix-list nbr-filter seq 20 deny 10.1.0.2/32")
+    r4.vtysh_cmd("conf t\ninterface r4-eth0\nip ospf neighbor-filter nbr-filter")
+
+    step(
+        "Add redistribution and spaced static routes to r1 to test delay flood retransmission"
+    )
+    r1.vtysh_cmd("conf t\nrouter ospf\nredistribute static")
+    r1.vtysh_cmd("conf t\nip route 20.1.1.1/32 null0")
+    sleep(1)
+    r1.vtysh_cmd("conf t\nip route 20.1.1.2/32 null0")
+    sleep(1)
+    r1.vtysh_cmd("conf t\nip route 20.1.1.3/32 null0")
+    sleep(1)
+    r1.vtysh_cmd("conf t\nip route 20.1.1.4/32 null0")
+    sleep(1)
+    r1.vtysh_cmd("conf t\nip route 20.1.1.5/32 null0")
+    sleep(1)
+
+    step(
+        "Verify the routes are installed on r1 with delay-reflood in P2MP partial mesh"
+    )
+    verify_p2mp_route(tgen, "r4", "20.1.1.1/32", 32, "10.1.0.3", "r4-eth0")
+    verify_p2mp_route(tgen, "r4", "20.1.1.2/32", 32, "10.1.0.3", "r4-eth0")
+    verify_p2mp_route(tgen, "r4", "20.1.1.3/32", 32, "10.1.0.3", "r4-eth0")
+    verify_p2mp_route(tgen, "r4", "20.1.1.4/32", 32, "10.1.0.3", "r4-eth0")
 
 
 def test_memory_leak():