diff --git a/src/NetworkManagerUtils.h b/src/NetworkManagerUtils.h
index d7fcb53033..f02849b661 100644
--- a/src/NetworkManagerUtils.h
+++ b/src/NetworkManagerUtils.h
@@ -33,6 +33,21 @@ gboolean nm_ethernet_address_is_valid (gconstpointer addr, gssize len);
 in_addr_t nm_utils_ip4_address_clear_host_address (in_addr_t addr, guint8 plen);
 void nm_utils_ip6_address_clear_host_address (struct in6_addr *dst, const struct in6_addr *src, guint8 plen);
 
+/**
+ * nm_utils_ip6_route_metric_normalize:
+ * @metric: the route metric
+ *
+ * For IPv6 route, kernel treats the value 0 as IP6_RT_PRIO_USER (1024).
+ * Thus, when comparing metric (values), we want to treat zero as NM_PLATFORM_ROUTE_METRIC_DEFAULT.
+ *
+ * Returns: @metric, if @metric is not zero, otherwise 1024.
+ */
+static inline guint32
+nm_utils_ip6_route_metric_normalize (guint32 metric)
+{
+	return metric ? metric : 1024 /*NM_PLATFORM_ROUTE_METRIC_DEFAULT*/;
+}
+
 int nm_spawn_process (const char *args);
 
 /* macro to return strlen() of a compile time string. */
diff --git a/src/platform/nm-platform.h b/src/platform/nm-platform.h
index cd2729cddf..13e25affbd 100644
--- a/src/platform/nm-platform.h
+++ b/src/platform/nm-platform.h
@@ -216,6 +216,8 @@ G_STATIC_ASSERT (G_STRUCT_OFFSET (NMPlatformIPAddress, address_ptr) == G_STRUCT_
 #undef __NMPlatformIPAddress_COMMON
 
 
+/* Adding an IPv6 route with metric 0, kernel translates to IP6_RT_PRIO_USER (1024).
+ * Thus, the value is not choosen arbitraily, but matches kernel IPv6 default. */
 #define NM_PLATFORM_ROUTE_METRIC_DEFAULT 1024
 
 #define __NMPlatformIPRoute_COMMON \