diff --git a/include/zenoh-pico/transport/common/tx.h b/include/zenoh-pico/transport/common/tx.h
index 634b38e2e..d11c1c80e 100644
--- a/include/zenoh-pico/transport/common/tx.h
+++ b/include/zenoh-pico/transport/common/tx.h
@@ -19,8 +19,8 @@
 #include "zenoh-pico/net/session.h"
 #include "zenoh-pico/transport/transport.h"
 
-void __unsafe_z_prepare_wbuf(_z_wbuf_t *buf, uint8_t link_capabilities);
-void __unsafe_z_finalize_wbuf(_z_wbuf_t *buf, uint8_t link_capabilities);
+void __unsafe_z_prepare_wbuf(_z_wbuf_t *buf, _z_link_cap_flow_t flow);
+void __unsafe_z_finalize_wbuf(_z_wbuf_t *buf, _z_link_cap_flow_t flow);
 /*This function is unsafe because it operates in potentially concurrent
         data.*Make sure that the following mutexes are locked before calling this function : *-ztu->mutex_tx */
 int8_t __unsafe_z_serialize_zenoh_fragment(_z_wbuf_t *dst, _z_wbuf_t *src, z_reliability_t reliability, size_t sn);
diff --git a/src/transport/common/rx.c b/src/transport/common/rx.c
index 2476a9b9a..8f25fff0f 100644
--- a/src/transport/common/rx.c
+++ b/src/transport/common/rx.c
@@ -28,10 +28,8 @@ int8_t _z_link_recv_t_msg(_z_transport_message_t *t_msg, const _z_link_t *zl) {
     _z_zbuf_t zbf = _z_zbuf_make(Z_BATCH_UNICAST_SIZE);
     _z_zbuf_reset(&zbf);
 
-    switch (zl->_capabilities) {
-        // Stream capable links
-        case Z_LINK_CAP_UNICAST_STREAM:
-        case Z_LINK_CAP_MULTICAST_STREAM:
+    switch (zl->_cap._flow) {
+        case Z_LINK_CAP_FLOW_STREAM:
             // Read the message length
             if (_z_link_recv_exact_zbuf(zl, &zbf, _Z_MSG_LEN_ENC_SIZE, NULL) == _Z_MSG_LEN_ENC_SIZE) {
                 size_t len = 0;
@@ -52,9 +50,7 @@ int8_t _z_link_recv_t_msg(_z_transport_message_t *t_msg, const _z_link_t *zl) {
                 ret = _Z_ERR_TRANSPORT_RX_FAILED;
             }
             break;
-        // Datagram capable links
-        case Z_LINK_CAP_UNICAST_DATAGRAM:
-        case Z_LINK_CAP_MULTICAST_DATAGRAM:
+        case Z_LINK_CAP_FLOW_DATAGRAM:
             if (_z_link_recv_zbuf(zl, &zbf, NULL) == SIZE_MAX) {
                 ret = _Z_ERR_TRANSPORT_RX_FAILED;
             }
diff --git a/src/transport/common/tx.c b/src/transport/common/tx.c
index ca17089c3..12fc69e24 100644
--- a/src/transport/common/tx.c
+++ b/src/transport/common/tx.c
@@ -27,21 +27,19 @@
  * Make sure that the following mutexes are locked before calling this function:
  *  - ztu->mutex_tx
  */
-void __unsafe_z_prepare_wbuf(_z_wbuf_t *buf, uint8_t link_capabilities) {
+void __unsafe_z_prepare_wbuf(_z_wbuf_t *buf, _z_link_cap_flow_t flow) {
     _z_wbuf_reset(buf);
 
-    switch (link_capabilities) {
+    switch (flow) {
         // Stream capable links
-        case Z_LINK_CAP_UNICAST_STREAM:
-        case Z_LINK_CAP_MULTICAST_STREAM:
+        case Z_LINK_CAP_FLOW_STREAM:
             for (uint8_t i = 0; i < _Z_MSG_LEN_ENC_SIZE; i++) {
                 _z_wbuf_put(buf, 0, i);
             }
             _z_wbuf_set_wpos(buf, _Z_MSG_LEN_ENC_SIZE);
             break;
         // Datagram capable links
-        case Z_LINK_CAP_UNICAST_DATAGRAM:
-        case Z_LINK_CAP_MULTICAST_DATAGRAM:
+        case Z_LINK_CAP_FLOW_DATAGRAM:
         default:
             break;
     }
@@ -52,11 +50,10 @@ void __unsafe_z_prepare_wbuf(_z_wbuf_t *buf, uint8_t link_capabilities) {
  * Make sure that the following mutexes are locked before calling this function:
  *  - ztu->mutex_tx
  */
-void __unsafe_z_finalize_wbuf(_z_wbuf_t *buf, uint8_t link_capabilities) {
-    switch (link_capabilities) {
+void __unsafe_z_finalize_wbuf(_z_wbuf_t *buf, _z_link_cap_flow_t flow) {
+    switch (flow) {
         // Stream capable links
-        case Z_LINK_CAP_UNICAST_STREAM:
-        case Z_LINK_CAP_MULTICAST_STREAM: {
+        case Z_LINK_CAP_FLOW_STREAM: {
             size_t len = _z_wbuf_len(buf) - _Z_MSG_LEN_ENC_SIZE;
             for (uint8_t i = 0; i < _Z_MSG_LEN_ENC_SIZE; i++) {
                 _z_wbuf_put(buf, (uint8_t)((len >> (uint8_t)8 * i) & (uint8_t)0xFF), i);
@@ -64,8 +61,7 @@ void __unsafe_z_finalize_wbuf(_z_wbuf_t *buf, uint8_t link_capabilities) {
             break;
         }
         // Datagram capable links
-        case Z_LINK_CAP_UNICAST_DATAGRAM:
-        case Z_LINK_CAP_MULTICAST_DATAGRAM:
+        case Z_LINK_CAP_FLOW_DATAGRAM:
         default:
             break;
     }
@@ -94,18 +90,14 @@ int8_t _z_link_send_t_msg(const _z_link_t *zl, const _z_transport_message_t *t_m
     uint16_t mtu = (zl->_mtu < Z_BATCH_UNICAST_SIZE) ? zl->_mtu : Z_BATCH_UNICAST_SIZE;
     _z_wbuf_t wbf = _z_wbuf_make(mtu, false);
 
-    switch (zl->_capabilities) {
-        // Stream capable links
-        case Z_LINK_CAP_UNICAST_STREAM:
-        case Z_LINK_CAP_MULTICAST_STREAM:
+    switch (zl->_cap._flow) {
+        case Z_LINK_CAP_FLOW_STREAM:
             for (uint8_t i = 0; i < _Z_MSG_LEN_ENC_SIZE; i++) {
                 _z_wbuf_put(&wbf, 0, i);
             }
             _z_wbuf_set_wpos(&wbf, _Z_MSG_LEN_ENC_SIZE);
             break;
-        // Datagram capable links
-        case Z_LINK_CAP_UNICAST_DATAGRAM:
-        case Z_LINK_CAP_MULTICAST_DATAGRAM:
+        case Z_LINK_CAP_FLOW_DATAGRAM:
             break;
         default:
             ret = _Z_ERR_GENERIC;
@@ -114,10 +106,8 @@ int8_t _z_link_send_t_msg(const _z_link_t *zl, const _z_transport_message_t *t_m
     // Encode the session message
     ret = _z_transport_message_encode(&wbf, t_msg);
     if (ret == _Z_RES_OK) {
-        switch (zl->_capabilities) {
-            // Stream capable links
-            case Z_LINK_CAP_UNICAST_STREAM:
-            case Z_LINK_CAP_MULTICAST_STREAM: {
+        switch (zl->_cap._flow) {
+            case Z_LINK_CAP_FLOW_STREAM: {
                 // Write the message length in the reserved space if needed
                 size_t len = _z_wbuf_len(&wbf) - _Z_MSG_LEN_ENC_SIZE;
                 for (uint8_t i = 0; i < _Z_MSG_LEN_ENC_SIZE; i++) {
@@ -125,9 +115,7 @@ int8_t _z_link_send_t_msg(const _z_link_t *zl, const _z_transport_message_t *t_m
                 }
                 break;
             }
-            // Datagram capable links
-            case Z_LINK_CAP_UNICAST_DATAGRAM:
-            case Z_LINK_CAP_MULTICAST_DATAGRAM:
+            case Z_LINK_CAP_FLOW_DATAGRAM:
                 break;
             default:
                 ret = _Z_ERR_GENERIC;
diff --git a/src/transport/manager.c b/src/transport/manager.c
index bc85a8dbc..7d8f79811 100644
--- a/src/transport/manager.c
+++ b/src/transport/manager.c
@@ -31,10 +31,9 @@ int8_t _z_new_transport_client(_z_transport_t *zt, char *locator, _z_id_t *local
         return ret;
     }
     // Open transport
-    switch (zl._capabilities) {
+    switch (zl._cap._transport) {
         // Unicast transport
-        case Z_LINK_CAP_UNICAST_STREAM:
-        case Z_LINK_CAP_UNICAST_DATAGRAM: {
+        case Z_LINK_CAP_TRANSPORT_UNICAST: {
             _z_transport_unicast_establish_param_t tp_param;
             ret = _z_unicast_open_client(&tp_param, &zl, local_zid);
             if (ret != _Z_RES_OK) {
@@ -45,8 +44,7 @@ int8_t _z_new_transport_client(_z_transport_t *zt, char *locator, _z_id_t *local
             break;
         }
         // Multicast transport
-        case Z_LINK_CAP_MULTICAST_STREAM:
-        case Z_LINK_CAP_MULTICAST_DATAGRAM: {
+        case Z_LINK_CAP_TRANSPORT_MULTICAST: {
             _z_transport_multicast_establish_param_t tp_param;
             ret = _z_multicast_open_client(&tp_param, &zl, local_zid);
             if (ret != _Z_RES_OK) {
@@ -73,10 +71,8 @@ int8_t _z_new_transport_peer(_z_transport_t *zt, char *locator, _z_id_t *local_z
     if (ret != _Z_RES_OK) {
         return ret;
     }
-    switch (zl._capabilities) {
-        // Unicast capable links
-        case Z_LINK_CAP_UNICAST_STREAM:
-        case Z_LINK_CAP_UNICAST_DATAGRAM: {
+    switch (zl._cap._transport) {
+        case Z_LINK_CAP_TRANSPORT_UNICAST: {
             _z_transport_unicast_establish_param_t tp_param;
             ret = _z_unicast_open_peer(&tp_param, &zl, local_zid);
             if (ret != _Z_RES_OK) {
@@ -86,9 +82,7 @@ int8_t _z_new_transport_peer(_z_transport_t *zt, char *locator, _z_id_t *local_z
             ret = _z_unicast_transport_create(zt, &zl, &tp_param);
             break;
         }
-        // Multicast capable links
-        case Z_LINK_CAP_MULTICAST_STREAM:
-        case Z_LINK_CAP_MULTICAST_DATAGRAM: {
+        case Z_LINK_CAP_TRANSPORT_MULTICAST: {
             _z_transport_multicast_establish_param_t tp_param;
             ret = _z_multicast_open_peer(&tp_param, &zl, local_zid);
             if (ret != _Z_RES_OK) {
diff --git a/src/transport/multicast/read.c b/src/transport/multicast/read.c
index ce221fe64..12073d0ce 100644
--- a/src/transport/multicast/read.c
+++ b/src/transport/multicast/read.c
@@ -73,10 +73,8 @@ void *_zp_multicast_read_task(void *ztm_arg) {
         // Read bytes from socket to the main buffer
         size_t to_read = 0;
 
-        switch (ztm->_link._capabilities) {
-            // Stream capable links
-            case Z_LINK_CAP_UNICAST_STREAM:
-            case Z_LINK_CAP_MULTICAST_STREAM:
+        switch (ztm->_link._cap._flow) {
+            case Z_LINK_CAP_FLOW_STREAM:
                 if (_z_zbuf_len(&ztm->_zbuf) < _Z_MSG_LEN_ENC_SIZE) {
                     _z_link_recv_zbuf(&ztm->_link, &ztm->_zbuf, &addr);
                     if (_z_zbuf_len(&ztm->_zbuf) < _Z_MSG_LEN_ENC_SIZE) {
@@ -99,9 +97,7 @@ void *_zp_multicast_read_task(void *ztm_arg) {
                     }
                 }
                 break;
-            // Datagram capable links
-            case Z_LINK_CAP_UNICAST_DATAGRAM:
-            case Z_LINK_CAP_MULTICAST_DATAGRAM:
+            case Z_LINK_CAP_FLOW_DATAGRAM:
                 _z_zbuf_compact(&ztm->_zbuf);
                 to_read = _z_link_recv_zbuf(&ztm->_link, &ztm->_zbuf, &addr);
                 if (to_read == SIZE_MAX) {
diff --git a/src/transport/multicast/rx.c b/src/transport/multicast/rx.c
index 0893b4307..5d43eb60c 100644
--- a/src/transport/multicast/rx.c
+++ b/src/transport/multicast/rx.c
@@ -59,10 +59,8 @@ int8_t _z_multicast_recv_t_msg_na(_z_transport_multicast_t *ztm, _z_transport_me
 
     size_t to_read = 0;
     do {
-        switch (ztm->_link._capabilities) {
-            // Stream capable links
-            case Z_LINK_CAP_UNICAST_STREAM:
-            case Z_LINK_CAP_MULTICAST_STREAM:
+        switch (ztm->_link._cap._flow) {
+            case Z_LINK_CAP_FLOW_STREAM:
                 if (_z_zbuf_len(&ztm->_zbuf) < _Z_MSG_LEN_ENC_SIZE) {
                     _z_link_recv_zbuf(&ztm->_link, &ztm->_zbuf, addr);
                     if (_z_zbuf_len(&ztm->_zbuf) < _Z_MSG_LEN_ENC_SIZE) {
@@ -85,8 +83,7 @@ int8_t _z_multicast_recv_t_msg_na(_z_transport_multicast_t *ztm, _z_transport_me
                 }
                 break;
             // Datagram capable links
-            case Z_LINK_CAP_UNICAST_DATAGRAM:
-            case Z_LINK_CAP_MULTICAST_DATAGRAM:
+            case Z_LINK_CAP_FLOW_DATAGRAM:
                 _z_zbuf_compact(&ztm->_zbuf);
                 to_read = _z_link_recv_zbuf(&ztm->_link, &ztm->_zbuf, addr);
                 if (to_read == SIZE_MAX) {
diff --git a/src/transport/multicast/tx.c b/src/transport/multicast/tx.c
index 94ff3c333..230c8c85a 100644
--- a/src/transport/multicast/tx.c
+++ b/src/transport/multicast/tx.c
@@ -50,13 +50,13 @@ int8_t _z_multicast_send_t_msg(_z_transport_multicast_t *ztm, const _z_transport
 #endif  // Z_FEATURE_MULTI_THREAD == 1
 
     // Prepare the buffer eventually reserving space for the message length
-    __unsafe_z_prepare_wbuf(&ztm->_wbuf, ztm->_link._capabilities);
+    __unsafe_z_prepare_wbuf(&ztm->_wbuf, ztm->_link._cap._flow);
 
     // Encode the session message
     ret = _z_transport_message_encode(&ztm->_wbuf, t_msg);
     if (ret == _Z_RES_OK) {
         // Write the message length in the reserved space if needed
-        __unsafe_z_finalize_wbuf(&ztm->_wbuf, ztm->_link._capabilities);
+        __unsafe_z_finalize_wbuf(&ztm->_wbuf, ztm->_link._cap._flow);
         // Send the wbuf on the socket
         ret = _z_link_send_wbuf(&ztm->_link, &ztm->_wbuf);
         if (ret == _Z_RES_OK) {
@@ -97,7 +97,7 @@ int8_t _z_multicast_send_n_msg(_z_session_t *zn, const _z_network_message_t *n_m
 
     if (drop == false) {
         // Prepare the buffer eventually reserving space for the message length
-        __unsafe_z_prepare_wbuf(&ztm->_wbuf, ztm->_link._capabilities);
+        __unsafe_z_prepare_wbuf(&ztm->_wbuf, ztm->_link._cap._flow);
 
         _z_zint_t sn = __unsafe_z_multicast_get_sn(ztm, reliability);  // Get the next sequence number
 
@@ -107,7 +107,7 @@ int8_t _z_multicast_send_n_msg(_z_session_t *zn, const _z_network_message_t *n_m
             ret = _z_network_message_encode(&ztm->_wbuf, n_msg);  // Encode the network message
             if (ret == _Z_RES_OK) {
                 // Write the message length in the reserved space if needed
-                __unsafe_z_finalize_wbuf(&ztm->_wbuf, ztm->_link._capabilities);
+                __unsafe_z_finalize_wbuf(&ztm->_wbuf, ztm->_link._cap._flow);
 
                 ret = _z_link_send_wbuf(&ztm->_link, &ztm->_wbuf);  // Send the wbuf on the socket
                 if (ret == _Z_RES_OK) {
@@ -128,13 +128,13 @@ int8_t _z_multicast_send_n_msg(_z_session_t *zn, const _z_network_message_t *n_m
                         is_first = false;
 
                         // Clear the buffer for serialization
-                        __unsafe_z_prepare_wbuf(&ztm->_wbuf, ztm->_link._capabilities);
+                        __unsafe_z_prepare_wbuf(&ztm->_wbuf, ztm->_link._cap._flow);
 
                         // Serialize one fragment
                         ret = __unsafe_z_serialize_zenoh_fragment(&ztm->_wbuf, &fbf, reliability, sn);
                         if (ret == _Z_RES_OK) {
                             // Write the message length in the reserved space if needed
-                            __unsafe_z_finalize_wbuf(&ztm->_wbuf, ztm->_link._capabilities);
+                            __unsafe_z_finalize_wbuf(&ztm->_wbuf, ztm->_link._cap._flow);
 
                             ret = _z_link_send_wbuf(&ztm->_link, &ztm->_wbuf);  // Send the wbuf on the socket
                             if (ret == _Z_RES_OK) {
diff --git a/src/transport/unicast/read.c b/src/transport/unicast/read.c
index d3fcbbdad..02b95ddef 100644
--- a/src/transport/unicast/read.c
+++ b/src/transport/unicast/read.c
@@ -68,10 +68,8 @@ void *_zp_unicast_read_task(void *ztu_arg) {
     while (ztu->_read_task_running == true) {
         // Read bytes from socket to the main buffer
         size_t to_read = 0;
-        switch (ztu->_link._capabilities) {
-            // Stream capable links
-            case Z_LINK_CAP_UNICAST_STREAM:
-            case Z_LINK_CAP_MULTICAST_STREAM:
+        switch (ztu->_link._cap._flow) {
+            case Z_LINK_CAP_FLOW_STREAM:
                 if (_z_zbuf_len(&ztu->_zbuf) < _Z_MSG_LEN_ENC_SIZE) {
                     _z_link_recv_zbuf(&ztu->_link, &ztu->_zbuf, NULL);
                     if (_z_zbuf_len(&ztu->_zbuf) < _Z_MSG_LEN_ENC_SIZE) {
@@ -93,9 +91,7 @@ void *_zp_unicast_read_task(void *ztu_arg) {
                     }
                 }
                 break;
-            // Datagram capable links
-            case Z_LINK_CAP_UNICAST_DATAGRAM:
-            case Z_LINK_CAP_MULTICAST_DATAGRAM:
+            case Z_LINK_CAP_FLOW_DATAGRAM:
                 _z_zbuf_compact(&ztu->_zbuf);
                 to_read = _z_link_recv_zbuf(&ztu->_link, &ztu->_zbuf, NULL);
                 if (to_read == SIZE_MAX) {
diff --git a/src/transport/unicast/rx.c b/src/transport/unicast/rx.c
index c5ee7748e..c1e3faa2d 100644
--- a/src/transport/unicast/rx.c
+++ b/src/transport/unicast/rx.c
@@ -37,10 +37,9 @@ int8_t _z_unicast_recv_t_msg_na(_z_transport_unicast_t *ztu, _z_transport_messag
 
     size_t to_read = 0;
     do {
-        switch (ztu->_link._capabilities) {
+        switch (ztu->_link._cap._flow) {
             // Stream capable links
-            case Z_LINK_CAP_UNICAST_STREAM:
-            case Z_LINK_CAP_MULTICAST_STREAM:
+            case Z_LINK_CAP_FLOW_STREAM:
                 if (_z_zbuf_len(&ztu->_zbuf) < _Z_MSG_LEN_ENC_SIZE) {
                     _z_link_recv_zbuf(&ztu->_link, &ztu->_zbuf, NULL);
                     if (_z_zbuf_len(&ztu->_zbuf) < _Z_MSG_LEN_ENC_SIZE) {
@@ -63,8 +62,7 @@ int8_t _z_unicast_recv_t_msg_na(_z_transport_unicast_t *ztu, _z_transport_messag
                 }
                 break;
             // Datagram capable links
-            case Z_LINK_CAP_UNICAST_DATAGRAM:
-            case Z_LINK_CAP_MULTICAST_DATAGRAM:
+            case Z_LINK_CAP_FLOW_DATAGRAM:
                 _z_zbuf_compact(&ztu->_zbuf);
                 to_read = _z_link_recv_zbuf(&ztu->_link, &ztu->_zbuf, NULL);
                 if (to_read == SIZE_MAX) {
diff --git a/src/transport/unicast/transport.c b/src/transport/unicast/transport.c
index 046b41630..15f660bd8 100644
--- a/src/transport/unicast/transport.c
+++ b/src/transport/unicast/transport.c
@@ -53,13 +53,11 @@ int8_t _z_unicast_transport_create(_z_transport_t *zt, _z_link_t *zl, _z_transpo
         size_t dbuf_size = 0;
         _Bool expandable = false;
 
-        switch (zl->_capabilities) {
-            case Z_LINK_CAP_UNICAST_STREAM:
-            case Z_LINK_CAP_MULTICAST_STREAM:
+        switch (zl->_cap._flow) {
+            case Z_LINK_CAP_FLOW_STREAM:
                 expandable = true;
                 break;
-            case Z_LINK_CAP_UNICAST_DATAGRAM:
-            case Z_LINK_CAP_MULTICAST_DATAGRAM:
+            case Z_LINK_CAP_FLOW_DATAGRAM:
             default:
                 expandable = false;
                 break;
diff --git a/src/transport/unicast/tx.c b/src/transport/unicast/tx.c
index 93997048a..21694e1e9 100644
--- a/src/transport/unicast/tx.c
+++ b/src/transport/unicast/tx.c
@@ -53,13 +53,13 @@ int8_t _z_unicast_send_t_msg(_z_transport_unicast_t *ztu, const _z_transport_mes
 #endif  // Z_FEATURE_MULTI_THREAD == 1
 
     // Prepare the buffer eventually reserving space for the message length
-    __unsafe_z_prepare_wbuf(&ztu->_wbuf, ztu->_link._capabilities);
+    __unsafe_z_prepare_wbuf(&ztu->_wbuf, ztu->_link._cap._flow);
 
     // Encode the session message
     ret = _z_transport_message_encode(&ztu->_wbuf, t_msg);
     if (ret == _Z_RES_OK) {
         // Write the message length in the reserved space if needed
-        __unsafe_z_finalize_wbuf(&ztu->_wbuf, ztu->_link._capabilities);
+        __unsafe_z_finalize_wbuf(&ztu->_wbuf, ztu->_link._cap._flow);
         // Send the wbuf on the socket
         ret = _z_link_send_wbuf(&ztu->_link, &ztu->_wbuf);
         if (ret == _Z_RES_OK) {
@@ -100,7 +100,7 @@ int8_t _z_unicast_send_n_msg(_z_session_t *zn, const _z_network_message_t *n_msg
 
     if (drop == false) {
         // Prepare the buffer eventually reserving space for the message length
-        __unsafe_z_prepare_wbuf(&ztu->_wbuf, ztu->_link._capabilities);
+        __unsafe_z_prepare_wbuf(&ztu->_wbuf, ztu->_link._cap._flow);
 
         _z_zint_t sn = __unsafe_z_unicast_get_sn(ztu, reliability);  // Get the next sequence number
 
@@ -110,7 +110,7 @@ int8_t _z_unicast_send_n_msg(_z_session_t *zn, const _z_network_message_t *n_msg
             ret = _z_network_message_encode(&ztu->_wbuf, n_msg);  // Encode the network message
             if (ret == _Z_RES_OK) {
                 // Write the message length in the reserved space if needed
-                __unsafe_z_finalize_wbuf(&ztu->_wbuf, ztu->_link._capabilities);
+                __unsafe_z_finalize_wbuf(&ztu->_wbuf, ztu->_link._cap._flow);
 
                 if (ztu->_wbuf._ioss._len == 1) {
                     ret = _z_link_send_wbuf(&ztu->_link, &ztu->_wbuf);  // Send the wbuf on the socket
@@ -137,13 +137,13 @@ int8_t _z_unicast_send_n_msg(_z_session_t *zn, const _z_network_message_t *n_msg
                         is_first = false;
 
                         // Clear the buffer for serialization
-                        __unsafe_z_prepare_wbuf(&ztu->_wbuf, ztu->_link._capabilities);
+                        __unsafe_z_prepare_wbuf(&ztu->_wbuf, ztu->_link._cap._flow);
 
                         // Serialize one fragment
                         ret = __unsafe_z_serialize_zenoh_fragment(&ztu->_wbuf, &fbf, reliability, sn);
                         if (ret == _Z_RES_OK) {
                             // Write the message length in the reserved space if needed
-                            __unsafe_z_finalize_wbuf(&ztu->_wbuf, ztu->_link._capabilities);
+                            __unsafe_z_finalize_wbuf(&ztu->_wbuf, ztu->_link._cap._flow);
 
                             ret = _z_link_send_wbuf(&ztu->_link, &ztu->_wbuf);  // Send the wbuf on the socket
                             if (ret == _Z_RES_OK) {