diff --git a/doc/user/ospf6d.rst b/doc/user/ospf6d.rst
index f8595ef3f5..948527d774 100644
--- a/doc/user/ospf6d.rst
+++ b/doc/user/ospf6d.rst
@@ -70,6 +70,20 @@ OSPF6 router
    Use this command to control the maximum number of parallel routes that
    OSPFv3 can support. The default is 64.
 
+.. clicmd:: area A.B.C.D range X:X::X:X/M [<advertise|not-advertise|cost (0-16777215)>]
+
+.. clicmd:: area (0-4294967295) range X:X::X:X/M [<advertise|not-advertise|cost (0-16777215)>]
+
+    Summarize a group of internal subnets into a single Inter-Area-Prefix LSA.
+    This command can only be used at the area boundary (ABR router).
+
+    By default, the metric of the summary route is calculated as the highest
+    metric among the summarized routes. The `cost` option, however, can be used
+    to set an explicit metric.
+
+    The `not-advertise` option, when present, prevents the summary route from
+    being advertised, effectively filtering the summarized routes.
+
 .. clicmd:: write-multiplier (1-100)
 
    Use this command to tune the amount of work done in the packet read and
diff --git a/ospf6d/ospf6_area.c b/ospf6d/ospf6_area.c
index f4d9964a57..0f1f061225 100644
--- a/ospf6d/ospf6_area.c
+++ b/ospf6d/ospf6_area.c
@@ -504,7 +504,7 @@ DEFUN (area_range,
 	struct ospf6_area *oa;
 	struct prefix prefix;
 	struct ospf6_route *range;
-	uint32_t cost = OSPF_AREA_RANGE_COST_UNSPEC;
+	uint32_t cost;
 
 	VTY_DECLVAR_CONTEXT(ospf6, ospf6);
 
@@ -526,16 +526,15 @@ DEFUN (area_range,
 		range->path.cost = OSPF_AREA_RANGE_COST_UNSPEC;
 	}
 
+	/* default settings */
+	cost = OSPF_AREA_RANGE_COST_UNSPEC;
+	UNSET_FLAG(range->flag, OSPF6_ROUTE_DO_NOT_ADVERTISE);
+
 	if (argc > idx_type) {
-		if (strmatch(argv[idx_type]->text, "not-advertise")) {
+		if (strmatch(argv[idx_type]->text, "not-advertise"))
 			SET_FLAG(range->flag, OSPF6_ROUTE_DO_NOT_ADVERTISE);
-		} else if (strmatch(argv[idx_type]->text, "advertise")) {
-			UNSET_FLAG(range->flag, OSPF6_ROUTE_DO_NOT_ADVERTISE);
-			cost = range->path.u.cost_config;
-		} else {
+		else if (strmatch(argv[idx_type]->text, "cost"))
 			cost = strtoul(argv[5]->arg, NULL, 10);
-			UNSET_FLAG(range->flag, OSPF6_ROUTE_DO_NOT_ADVERTISE);
-		}
 	}
 
 	range->path.u.cost_config = cost;