diff --git a/core/federated/RTI/rti_remote.c b/core/federated/RTI/rti_remote.c
index cc0252843..d006ab3f3 100644
--- a/core/federated/RTI/rti_remote.c
+++ b/core/federated/RTI/rti_remote.c
@@ -923,7 +923,7 @@ void* clock_synchronization_thread(void* noargs) {
       send_physical_clock(MSG_TYPE_CLOCK_SYNC_T1, fed, UDP);
 
       // Listen for reply message, which should be T3.
-      size_t message_size = 1 + sizeof(int32_t);
+      size_t message_size = 1 + sizeof(uint16_t);
       unsigned char buffer[message_size];
       // Maximum number of messages that we discard before giving up on this cycle.
       // If the T3 message from this federate does not arrive and we keep receiving
@@ -935,7 +935,7 @@ void* clock_synchronization_thread(void* noargs) {
         // If any errors occur, either discard the message or the clock sync round.
         if (!read_failed) {
           if (buffer[0] == MSG_TYPE_CLOCK_SYNC_T3) {
-            int32_t fed_id_2 = extract_int32(&(buffer[1]));
+            int32_t fed_id_2 = (int32_t) extract_uint16(&(buffer[1]));
             // Check that this message came from the correct federate.
             if (fed_id_2 != fed->enclave.id) {
               // Message is from the wrong federate. Discard the message.
diff --git a/core/federated/clock-sync.c b/core/federated/clock-sync.c
index b18efb650..ef5403c89 100644
--- a/core/federated/clock-sync.c
+++ b/core/federated/clock-sync.c
@@ -275,13 +275,13 @@ int handle_T1_clock_sync_message(unsigned char* buffer, int socket, instant_t t2
   // T3-T2 between receiving the T1 message and replying.
 
   // Reply will have the federate ID as a payload.
-  unsigned char reply_buffer[1 + sizeof(int)];
+  unsigned char reply_buffer[1 + sizeof(uint16_t)];
   reply_buffer[0] = MSG_TYPE_CLOCK_SYNC_T3;
-  encode_int32(_lf_my_fed_id, &(reply_buffer[1]));
+  encode_uint16(_lf_my_fed_id, &(reply_buffer[1]));
 
   // Write the reply to the socket.
   LF_PRINT_DEBUG("Sending T3 message to RTI.");
-  if (write_to_socket(socket, 1 + sizeof(int), reply_buffer)) {
+  if (write_to_socket(socket, 1 + sizeof(uint16_t), reply_buffer)) {
     lf_print_error("Clock sync: Failed to send T3 message to RTI.");
     return -1;
   }
diff --git a/core/utils/util.c b/core/utils/util.c
index 62de9fd27..721c2d977 100644
--- a/core/utils/util.c
+++ b/core/utils/util.c
@@ -58,7 +58,7 @@ THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  * The ID of this federate. For a non-federated execution, this will be -1.
  * For a federated execution, it will be assigned in the generated code.
  */
-int _lf_my_fed_id = -1;
+int32_t _lf_my_fed_id = -1;
 
 /**
  * If non-null, this function will be used instead of the printf to