diff --git a/headers/packet_interface.h b/headers/packet_interface.h
index c4d5583f77b1fc3d10b161ac0558f3a52a7a7e9a..2b51cbf2093fb687d13b33630c1c751faf30faed 100644
--- a/headers/packet_interface.h
+++ b/headers/packet_interface.h
@@ -15,6 +15,9 @@
 #define MAX_PAYLOAD_SIZE 512
 /* Taille maximale de Window */
 #define MAX_WINDOW_SIZE 31
+/* Taille maximale de seqnum */
+#define MAX_SEQNUM_SIZE 255
+
 
 #define member_size(type, member) sizeof((((type *) NULL)->member))
 
diff --git a/src/sender.c b/src/sender.c
index ce02d155bc9701f59ef3ad36ec24c3e7ea3992e1..3f3e53eb7d2d177e35ad2722c8b2b1df9e88f6d1 100644
--- a/src/sender.c
+++ b/src/sender.c
@@ -49,7 +49,7 @@ int main(int argc, char **argv) {
     DEBUG_DUMP("Some bytes", 11); // You can use it with any pointer type
 
     // This is not an error per-se.
-    ERROR("Sender has following arguments: \tfilename is %s,\n\t stats_filename is %s,\n\t fec_enabled is %d,\n\t receiver_ip is %s,\n\t receiver_port is %u",
+    ERROR("Sender has following arguments: \n\tfilename is %s,\n\t stats_filename is %s,\n\t fec_enabled is %d,\n\t receiver_ip is %s,\n\t receiver_port is %u\n",
         filename, stats_filename, fec_enabled, receiver_ip, receiver_port);
 
     DEBUG("You can only see me if %s", "you built me using `make debug`");
@@ -87,17 +87,21 @@ int main(int argc, char **argv) {
 
     
     // *** Step: Time for sending ***
-    // pkt_t buffer[MAX_WINDOW_SIZE];
-    // int buffer_space = MAX_WINDOW_SIZE;
-    // int seqnum = 0;
+    // pkt_t buffer[MAX_WINDOW_SIZE]; not used for now
+    int buffer_space = MAX_WINDOW_SIZE;
+    int seqnum = 0;
     
     pkt_t *pkt = pkt_new();
     ssize_t nbr_byte_read = read(fd, pkt->payload, MAX_PAYLOAD_SIZE);
     while (nbr_byte_read > 0)
     {
-        // *** Step: Prepare the paquet to be send ***
+        // *** Step: Prepare the packet to be send ***
         pkt_set_type(pkt, PTYPE_DATA);
+        pkt_set_tr(pkt, 0);
+        pkt_set_window(pkt, buffer_space);
         pkt_set_length(pkt, nbr_byte_read);
+        pkt_set_seqnum(pkt, (seqnum++) % MAX_SEQNUM_SIZE);
+        pkt_set_timestamp(pkt, 0); // We're free to use as we want
         
         // We set the TR to 0 in order to calculcate the CRC on the header
         char modified_header[8];