diff --git a/makefiles/pseudomodules.inc.mk b/makefiles/pseudomodules.inc.mk
index 7359f6086257f..4e3c36601412c 100644
--- a/makefiles/pseudomodules.inc.mk
+++ b/makefiles/pseudomodules.inc.mk
@@ -59,6 +59,10 @@ PSEUDOMODULES += gnrc_sixloenc
 PSEUDOMODULES += gnrc_sixlowpan_border_router_default
 PSEUDOMODULES += gnrc_sixlowpan_default
 PSEUDOMODULES += gnrc_sixlowpan_frag_hint
+PSEUDOMODULES += gnrc_sixlowpan_frag_sfr_ecn
+PSEUDOMODULES += gnrc_sixlowpan_frag_sfr_ecn_if_in
+PSEUDOMODULES += gnrc_sixlowpan_frag_sfr_ecn_if_out
+PSEUDOMODULES += gnrc_sixlowpan_frag_sfr_ecn_fqueue
 PSEUDOMODULES += gnrc_sixlowpan_frag_sfr_stats
 PSEUDOMODULES += gnrc_sixlowpan_iphc_nhc
 PSEUDOMODULES += gnrc_sixlowpan_nd_border_router
diff --git a/sys/Makefile.dep b/sys/Makefile.dep
index e441215437ce9..0a425f21bd55f 100644
--- a/sys/Makefile.dep
+++ b/sys/Makefile.dep
@@ -344,6 +344,18 @@ ifneq (,$(filter gnrc_sixlowpan_frag_sfr,$(USEMODULE)))
   endif
 endif
 
+ifneq (,$(filter gnrc_sixlowpan_frag_sfr_ecn_%,$(USEMODULE)))
+  USEMODULE += gnrc_sixlowpan_frag_sfr_ecn
+endif
+
+ifneq (,$(filter gnrc_sixlowpan_frag_sfr_ecn_if_out,$(USEMODULE)))
+  USEMODULE += gnrc_netif_pktq
+endif
+
+ifneq (,$(filter gnrc_sixlowpan_frag_sfr_ecn,$(USEMODULE)))
+  USEMODULE += gnrc_sixlowpan_frag_sfr
+endif
+
 ifneq (,$(filter gnrc_sixlowpan_frag_sfr_stats,$(USEMODULE)))
   USEMODULE += gnrc_sixlowpan_frag_sfr
 endif
diff --git a/sys/include/net/gnrc/sixlowpan/config.h b/sys/include/net/gnrc/sixlowpan/config.h
index 343d17bb6c759..f13cf10e4ef13 100644
--- a/sys/include/net/gnrc/sixlowpan/config.h
+++ b/sys/include/net/gnrc/sixlowpan/config.h
@@ -301,6 +301,84 @@ extern "C" {
 #ifndef CONFIG_GNRC_SIXLOWPAN_SFR_DG_RETRIES
 #define CONFIG_GNRC_SIXLOWPAN_SFR_DG_RETRIES            0U
 #endif
+
+/**
+ * @brief   The denominator for the factor for when to mark ECN on `netif` input
+ *          queue state
+ *
+ * When `gnrc_sixlowpan_frag_sfr_ecn_if_in` is compiled in, nodes will set
+ * the ECN bit of an RFRAG header when the input queue of the outgoing `netif`
+ * is filled by
+ * @ref CONFIG_GNRC_SIXLOWPAN_SFR_ECN_IF_IN_NUM / @ref CONFIG_GNRC_SIXLOWPAN_SFR_ECN_IF_IN_DEN
+ */
+#ifndef CONFIG_GNRC_SIXLOWPAN_SFR_ECN_IF_IN_NUM
+#define CONFIG_GNRC_SIXLOWPAN_SFR_ECN_IF_IN_NUM         1U
+#endif
+
+/**
+ * @brief   The denominator for the factor for when to mark ECN on `netif` input
+ *          queue state
+ *
+ * When `gnrc_sixlowpan_frag_sfr_ecn_if_in` is compiled in, nodes will set the
+ * ECN bit of an RFRAG header when the input queue of the outgoing `netif` is
+ * filled by
+ * @ref CONFIG_GNRC_SIXLOWPAN_SFR_ECN_IF_IN_NUM / @ref CONFIG_GNRC_SIXLOWPAN_SFR_ECN_IF_IN_DEN
+ */
+#ifndef CONFIG_GNRC_SIXLOWPAN_SFR_ECN_IF_IN_DEN
+#define CONFIG_GNRC_SIXLOWPAN_SFR_ECN_IF_IN_DEN         2U
+#endif
+
+/**
+ * @brief   The denominator for the factor for when to mark ECN on `netif`
+ *          output queue state
+ *
+ * When `gnrc_sixlowpan_frag_sfr_ecn_if_out` is compiled in, nodes will set
+ * the ECN bit of an RFRAG header when the output queue of the outgoing `netif`
+ * is filled by
+ * @ref CONFIG_GNRC_SIXLOWPAN_SFR_ECN_IF_OUT_NUM / @ref CONFIG_GNRC_SIXLOWPAN_SFR_ECN_IF_OUT_DEN
+ */
+#ifndef CONFIG_GNRC_SIXLOWPAN_SFR_ECN_IF_OUT_NUM
+#define CONFIG_GNRC_SIXLOWPAN_SFR_ECN_IF_OUT_NUM        1U
+#endif
+
+/**
+ * @brief   The denominator for the factor for when to mark ECN on `netif`
+ *          output queue state
+ *
+ * When `gnrc_sixlowpan_frag_sfr_ecn_if_out` is compiled in, nodes will set the
+ * ECN bit of an RFRAG header when the output queue of the outgoing `netif` is
+ * filled by
+ * @ref CONFIG_GNRC_SIXLOWPAN_SFR_ECN_IF_OUT_NUM / @ref CONFIG_GNRC_SIXLOWPAN_SFR_ECN_IF_OUT_DEN
+ */
+#ifndef CONFIG_GNRC_SIXLOWPAN_SFR_ECN_IF_OUT_DEN
+#define CONFIG_GNRC_SIXLOWPAN_SFR_ECN_IF_OUT_DEN        2U
+#endif
+
+/**
+ * @brief   The numerator for the factor for when to mark ECN on frame queue
+ *          state
+ *
+ * When `gnrc_sixlowpan_frag_sfr_ecn_fqueue` is compiled in, nodes will set the
+ * ECN bit of an RFRAG header when the input queue of the outgoing `netif` is
+ * filled by
+ * @ref CONFIG_GNRC_SIXLOWPAN_SFR_ECN_FQUEUE_NUM / @ref CONFIG_GNRC_SIXLOWPAN_SFR_ECN_FQUEUE_DEN
+ */
+#ifndef CONFIG_GNRC_SIXLOWPAN_SFR_ECN_FQUEUE_NUM
+#define CONFIG_GNRC_SIXLOWPAN_SFR_ECN_FQUEUE_NUM        1U
+#endif
+
+/**
+ * @brief   The denominator for the factor for when to mark ECN on frame queue
+ *          state
+ *
+ * When `gnrc_sixlowpan_frag_sfr_ecn_fqueue` is compiled in, nodes will set the
+ * ECN bit of an RFRAG header when the input queue of the outgoing `netif` is
+ * filled by
+ * @ref CONFIG_GNRC_SIXLOWPAN_SFR_ECN_FQUEUE_NUM / @ref CONFIG_GNRC_SIXLOWPAN_SFR_ECN_FQUEUE_DEN
+ */
+#ifndef CONFIG_GNRC_SIXLOWPAN_SFR_ECN_FQUEUE_DEN
+#define CONFIG_GNRC_SIXLOWPAN_SFR_ECN_FQUEUE_DEN        2U
+#endif
 /** @} */
 
 /**
diff --git a/sys/net/gnrc/network_layer/sixlowpan/frag/sfr/Kconfig b/sys/net/gnrc/network_layer/sixlowpan/frag/sfr/Kconfig
index 3db6a9e11a205..a7a9ef739772f 100644
--- a/sys/net/gnrc/network_layer/sixlowpan/frag/sfr/Kconfig
+++ b/sys/net/gnrc/network_layer/sixlowpan/frag/sfr/Kconfig
@@ -98,4 +98,54 @@ config GNRC_SIXLOWPAN_SFR_DG_RETRIES
     int "The maximum number of retries from scratch for a particular datagram (MaxDatagramRetries)"
     default 0
 
+menuconfig KCONFIG_USEMODULE_GNRC_SIXLOWPAN_FRAG_SFR_ECN_NETIF
+    bool "Configure SFR ECN based on netif queue"
+    depends on USEMODULE_GNRC_SIXLOWPAN_FRAG_SFR_ECN_NETIF
+
+if KCONFIG_USEMODULE_GNRC_SIXLOWPAN_FRAG_SFR_ECN_NETIF
+config GNRC_SIXLOWPAN_SFR_ECN_NETIF_NUM
+    int "The numerator for the factor for when to mark ECN on `netif` queue state"
+    default 1
+    help
+        When `gnrc_sixlowpan_frag_sfr_ecn_netif` is compiled in, nodes will set
+        the ECN bit of an RFRAG header when the input queue of the outgoing
+        `netif` is filled by
+        @ref CONFIG_GNRC_SIXLOWPAN_SFR_ECN_NETIF_NUM / @ref CONFIG_GNRC_SIXLOWPAN_SFR_ECN_NETIF_DEN
+
+
+config GNRC_SIXLOWPAN_SFR_ECN_NETIF_DEN
+    int "The denominator for the factor for when to mark ECN on `netif` queue state"
+    default 2
+    help
+        When `gnrc_sixlowpan_frag_sfr_ecn_netif` is compiled in, nodes will set
+        the ECN bit of an RFRAG header when the input queue of the outgoing
+        `netif` is filled by
+        @ref CONFIG_GNRC_SIXLOWPAN_SFR_ECN_NETIF_NUM / @ref CONFIG_GNRC_SIXLOWPAN_SFR_ECN_NETIF_DEN
+endif
+
+menuconfig KCONFIG_USEMODULE_GNRC_SIXLOWPAN_FRAG_SFR_ECN_FQUEUE
+    bool "Configure SFR ECN based on SFR's frame queue"
+    depends on USEMODULE_GNRC_SIXLOWPAN_FRAG_SFR_ECN_FQUEUE
+
+if KCONFIG_USEMODULE_GNRC_SIXLOWPAN_FRAG_SFR_ECN_FQUEUE
+config GNRC_SIXLOWPAN_SFR_ECN_FQUEUE_NUM
+    int "The numerator for the factor for when to mark ECN on frame queue state"
+    default 1
+    help
+        When `gnrc_sixlowpan_frag_sfr_ecn_fqueue` is compiled in, nodes will set
+        the ECN bit of an RFRAG header when the input queue of the outgoing
+        `netif` is filled by
+        @ref CONFIG_GNRC_SIXLOWPAN_SFR_ECN_FQUEUE_NUM / @ref CONFIG_GNRC_SIXLOWPAN_SFR_ECN_FQUEUE_DEN
+
+
+config GNRC_SIXLOWPAN_SFR_ECN_FQUEUE_DEN
+    int "The denominator for the factor for when to mark ECN on frame queue state"
+    default 2
+    help
+        When `gnrc_sixlowpan_frag_sfr_ecn_fqueue` is compiled in, nodes will set
+        the ECN bit of an RFRAG header when the input queue of the outgoing
+        `netif` is filled by
+        @ref CONFIG_GNRC_SIXLOWPAN_SFR_ECN_FQUEUE_NUM / @ref CONFIG_GNRC_SIXLOWPAN_SFR_ECN_FQUEUE_DEN
+endif
+
 endif
diff --git a/sys/net/gnrc/network_layer/sixlowpan/frag/sfr/gnrc_sixlowpan_frag_sfr.c b/sys/net/gnrc/network_layer/sixlowpan/frag/sfr/gnrc_sixlowpan_frag_sfr.c
index 8058a5b545c62..fb0af55daf35e 100644
--- a/sys/net/gnrc/network_layer/sixlowpan/frag/sfr/gnrc_sixlowpan_frag_sfr.c
+++ b/sys/net/gnrc/network_layer/sixlowpan/frag/sfr/gnrc_sixlowpan_frag_sfr.c
@@ -23,6 +23,7 @@
 #endif
 #include "net/gnrc/neterr.h"
 #include "net/gnrc/netif/internal.h"
+#include "net/gnrc/netif/pktq.h"
 #include "net/gnrc/pkt.h"
 #include "net/gnrc/sixlowpan.h"
 #include "net/gnrc/sixlowpan/config.h"
@@ -548,6 +549,51 @@ void gnrc_sixlowpan_frag_sfr_arq_timeout(gnrc_sixlowpan_frag_fb_t *fbuf)
     _clean_up_fbuf(fbuf, error_no);
 }
 
+static void _6lo_dispatch_send(gnrc_pktsnip_t *frame, void *ctx, unsigned page)
+{
+    if (IS_USED(MODULE_GNRC_SIXLOWPAN_FRAG_SFR_ECN) &&
+        (sixlowpan_sfr_rfrag_is(frame->next->data))) {
+        int queue_state = 0;
+        int queue_size = 0;
+
+        if (IS_USED(MODULE_GNRC_SIXLOWPAN_FRAG_SFR_ECN_IF_IN)) {
+            gnrc_netif_t *netif = gnrc_netif_hdr_get_netif(frame->data);
+
+            assert(frame->type == GNRC_NETTYPE_NETIF);
+            assert(frame->next->type == GNRC_NETTYPE_SIXLOWPAN);
+            queue_state = msg_avail_thread(netif->pid);
+            queue_size = msg_queue_capacity(netif->pid);
+            assert(queue_size > 0);
+
+            if ((queue_state * CONFIG_GNRC_SIXLOWPAN_SFR_ECN_IF_IN_DEN) >
+                (queue_size * CONFIG_GNRC_SIXLOWPAN_SFR_ECN_IF_IN_NUM)) {
+                sixlowpan_sfr_set_ecn(frame->next->data);
+            }
+        }
+
+        if (IS_USED(MODULE_GNRC_SIXLOWPAN_FRAG_SFR_ECN_IF_OUT)) {
+            queue_state = gnrc_netif_pktq_usage();
+            queue_size = CONFIG_GNRC_NETIF_PKTQ_POOL_SIZE;
+
+            if ((queue_state * CONFIG_GNRC_SIXLOWPAN_SFR_ECN_IF_OUT_DEN) >
+                ((unsigned)queue_size * CONFIG_GNRC_SIXLOWPAN_SFR_ECN_IF_OUT_NUM)) {
+                sixlowpan_sfr_set_ecn(frame->next->data);
+            }
+        }
+
+        if (IS_USED(MODULE_GNRC_SIXLOWPAN_FRAG_SFR_ECN_FQUEUE)) {
+            queue_state = clist_count(&_frame_queue);
+            queue_size = FRAME_QUEUE_POOL_SIZE;
+
+            if ((queue_state * CONFIG_GNRC_SIXLOWPAN_SFR_ECN_FQUEUE_DEN) >
+                (queue_size * CONFIG_GNRC_SIXLOWPAN_SFR_ECN_FQUEUE_NUM)) {
+                sixlowpan_sfr_set_ecn(frame->next->data);
+            }
+        }
+    }
+    gnrc_sixlowpan_dispatch_send(frame, ctx, page);
+}
+
 void gnrc_sixlowpan_frag_sfr_inter_frame_gap(void)
 {
     if (CONFIG_GNRC_SIXLOWPAN_SFR_INTER_FRAME_GAP_US > 0) {
@@ -555,7 +601,7 @@ void gnrc_sixlowpan_frag_sfr_inter_frame_gap(void)
 
         if (node != NULL) {
             _last_frame_sent = xtimer_now_usec();
-            gnrc_sixlowpan_dispatch_send(node->frame, NULL, node->page);
+            _6lo_dispatch_send(node->frame, NULL, node->page);
             /* unset packet just to be safe */
             node->frame = NULL;
             clist_rpush(&_frame_queue_free, &node->super);
@@ -747,7 +793,7 @@ static bool _send_frame(gnrc_pktsnip_t *frame, void *ctx, unsigned page)
         ((now - _last_frame_sent) > CONFIG_GNRC_SIXLOWPAN_SFR_INTER_FRAME_GAP_US)) {
         DEBUG("6lo sfr: dispatch frame to network interface\n");
         _last_frame_sent = now;
-        gnrc_sixlowpan_dispatch_send(frame, ctx, page);
+        _6lo_dispatch_send(frame, ctx, page);
         return true;
     }
     else {