diff --git a/src/algo_dup2.c b/src/algo_dup2.c
index 30b8e73..530f20e 100644
--- a/src/algo_dup2.c
+++ b/src/algo_dup2.c
@@ -22,15 +22,15 @@ int algo_dup2_on_stream(struct evt_core_ctx* ctx, struct evt_core_fdinfo* fdinfo
 
   // Check that we didn't already received the packet
   struct dup2_ctx* dup2c = app_ctx->misc;
-  if (ring_ge(dup2c->recv_id, bp->ip.ap.str.id)) {
+  if (ring_ge(dup2c->recv_id, bp->ip.ap.fmt.content.clear.id)) {
     mv_buffer_rtof(app_ctx, fdinfo);
     return 0;
   }
 
-  dup2c->recv_id = bp->ip.ap.str.id;
+  dup2c->recv_id = bp->ip.ap.fmt.content.clear.id;
 
   // 1. Find destination
-  sprintf(url, "udp:write:127.0.0.1:%d", bp->ip.ap.str.port);
+  sprintf(url, "udp:write:127.0.0.1:%d", bp->ip.ap.fmt.content.clear.port);
   to_fdinfo = evt_core_get_from_url (ctx, url);
   if (to_fdinfo == NULL) {
     fprintf(stderr, "No fd for URL %s in tcp-read. Dropping packet :( \n", url);
@@ -49,7 +49,7 @@ int algo_dup2_on_datagram(struct evt_core_ctx* ctx, struct evt_core_fdinfo* fdin
   struct algo_ctx* app_ctx = fdinfo->cat->app_ctx;
 
   struct dup2_ctx* dup2c = app_ctx->misc;
-  bp->ip.ap.str.id = dup2c->emit_id;
+  bp->ip.ap.fmt.content.clear.id = dup2c->emit_id;
   dup2c->emit_id = dup2c->emit_id + 1;
 
   struct evt_core_cat* cat = evt_core_get_from_cat (ctx, "tcp-write");
diff --git a/src/algo_naive.c b/src/algo_naive.c
index 17a7d99..90afdaa 100644
--- a/src/algo_naive.c
+++ b/src/algo_naive.c
@@ -11,7 +11,7 @@ int algo_naive_on_stream(struct evt_core_ctx* ctx, struct evt_core_fdinfo* fdinf
   struct algo_ctx* app_ctx = fdinfo->cat->app_ctx;
 
   // 1. Find destination
-  sprintf(url, "udp:write:127.0.0.1:%d", bp->ip.ap.str.port);
+  sprintf(url, "udp:write:127.0.0.1:%d", bp->ip.ap.fmt.content.clear.port);
   to_fdinfo = evt_core_get_from_url (ctx, url);
   if (to_fdinfo == NULL) {
     fprintf(stderr, "No fd for URL %s in tcp-read. Dropping packet :( \n", url);
diff --git a/src/algo_rr.c b/src/algo_rr.c
index c251b10..440e903 100644
--- a/src/algo_rr.c
+++ b/src/algo_rr.c
@@ -5,34 +5,35 @@
 #include "proxy.h"
 #include "timer.h"
 
-struct waited_pkt {
-  uint16_t id;
-  int link_num;
-  uint8_t on;
+struct timer_info {
+  uint16_t health_id;
+  uint8_t prevlink;
+  uint16_t min_blocked_pkt;
   struct algo_ctx* algo;
 };
 
-struct deferred_pkt {
+struct queued_pkt {
+  uint8_t on;
   int link_fd;
   int idx;
   uint16_t id;
-  uint8_t on;
   struct algo_ctx* algo;
 };
 
 struct rr_ctx {
   uint8_t my_links;
-  uint16_t my_links_ver;
   uint8_t remote_links;
-  int64_t mjit;
-  uint16_t recv_id;
-  uint16_t recv_id_late;
-  uint16_t sent_id;
   uint8_t current_link;
+  int64_t mjit;
+  uint16_t health_id;
+  uint16_t health_id_late;
+  uint16_t content_id;
+  uint16_t sent_health_id;
+  uint16_t sent_content_id;
   struct internet_packet prev_packet;
   struct timespec emit_time;
-  struct deferred_pkt real[PACKET_BUFFER_SIZE];
-  struct waited_pkt wait[PACKET_BUFFER_SIZE];
+  struct queued_pkt real[PACKET_BUFFER_SIZE];
+  struct timer_info wait[PACKET_BUFFER_SIZE];
 };
 
 void show_link_availability(struct rr_ctx* rr) {
@@ -49,110 +50,53 @@ void show_link_availability(struct rr_ctx* rr) {
   printf("]\n");
 }
 
-void expired_wait (struct evt_core_ctx* ctx, void* user);
-void expired_late(struct evt_core_ctx* ctx, void* user);
+void on_timeout_health (struct evt_core_ctx* ctx, void* user);
 
 void rr_pkt_register(struct evt_core_ctx* ctx,  struct evt_core_fdinfo* fdinfo, struct buffer_packet* bp) {
   struct algo_ctx* app_ctx = fdinfo->cat->app_ctx;
   struct rr_ctx* rr = app_ctx->misc;
-  char buffer[16];
-  url_get_port (buffer, fdinfo->url);
-  int link_num = atoi(buffer) - 7500; // @FIXME Hardcoded
-  uint16_t real_idx = bp->ip.ap.str.id % PACKET_BUFFER_SIZE;
-  uint16_t wait_idx = (bp->ip.ap.str.id - 1) % PACKET_BUFFER_SIZE;
+  uint16_t real_idx = bp->ip.ap.fmt.content.clear.id % PACKET_BUFFER_SIZE;
 
-  //printf("Selected url %s for pkt %d to be queued for delivery\n", fdinfo->url, bp->ip.ap.str.id);
+  assert(bp->ip.ap.headers.cmd == CMD_CLEAR);
 
-  // 0. Update remote links
-  if (ring_lt(rr->recv_id_late, bp->ip.ap.str.id) && !(rr->remote_links & 1 << link_num)) {
-    printf("Activate link=%d | ", link_num);
-    rr->remote_links |= 1 << link_num; // Make sure that the link is marked as working
-    show_link_availability (rr);
-  }
-
-  // 1. Update my links I can use thanks to target feedback
-  if (bp->ip.ap.str.id > rr->my_links_ver && bp->ip.ap.str.bitfield != rr->my_links) {
-    rr->my_links = bp->ip.ap.str.bitfield;
-    rr->my_links_ver = bp->ip.ap.str.id;
-    printf("Update my links | ");
-    show_link_availability (rr);
-  }
-
-  // 2. If packet arrived too late or already queued, we discard it
-  if (ring_ge(rr->recv_id, bp->ip.ap.str.id) || rr->real[real_idx].id == bp->ip.ap.str.id) {
-    // Packet has already been delivered or dropped, we free the buffer
-    fprintf(stderr, "Packet %d arrived too late (current: %d) or already received\n", bp->ip.ap.str.id, rr->recv_id);
-    mv_buffer_wtof (app_ctx, fdinfo);
-    return;
-  }
-
-  // 3. If packet arrived too early, we wait for its predecessors
-  //printf("%d < %d = %d\n", rr->recv_id, bp->ip.ap.str.id - 1, ring_lt(rr->recv_id, bp->ip.ap.str.id - 1));
-  if (ring_lt(rr->recv_id, bp->ip.ap.str.id - 1)) {
-    int64_t timeout = rr->mjit - (int64_t) bp->ip.ap.str.deltat;
-    //printf("%ld - %ld = %ld\n", rr->mjit, (int64_t) bp->ip.ap.str.deltat, timeout);
-    if (timeout <= 0) timeout = 0;
-
-    if (rr->wait[wait_idx].on && rr->wait[wait_idx].id != bp->ip.ap.str.id - 1) {
-      fprintf(stderr, "Waiting array overlap, BUG: [\n");
-      for (int i = 0; i < PACKET_BUFFER_SIZE; i++) {
-        printf("\t%d => %d\n", rr->wait[i].id, rr->wait[i].on);
-      }
-      printf("] - could be replaced by drop\n");
-      exit(EXIT_FAILURE);
-    } else if (!rr->wait[wait_idx].on) {
-      rr->wait[wait_idx].on = 1;
-      rr->wait[wait_idx].id = bp->ip.ap.str.id - 1;
-      rr->wait[wait_idx].link_num = bp->ip.ap.str.prevlink;
-      rr->wait[wait_idx].algo = app_ctx;
-      set_timeout(ctx, timeout, &rr->wait[wait_idx], expired_wait);
-    }
-  }
-
-  // 4. We queue the packet to keep it
-  if (rr->real[real_idx].on && rr->real[real_idx].id != bp->ip.ap.str.id) {
-    fprintf(stderr, "Real array is full for id=%d, idx=%d, BUG: [\n", bp->ip.ap.str.id, real_idx);
+  // 1. We queue the packet to keep it
+  if (rr->real[real_idx].on && rr->real[real_idx].id != bp->ip.ap.fmt.content.clear.id) {
+    fprintf(stderr, "Real array is full for id=%d, idx=%d, BUG: [\n", bp->ip.ap.fmt.content.clear.id, real_idx);
     for (int i = 0; i < PACKET_BUFFER_SIZE; i++) {
       printf("\t%d => %d\n", rr->real[i].id, rr->real[i].on);
     }
     printf("] - could be replaced by drop\n");
     exit(EXIT_FAILURE);
-  } else if (!rr->real[real_idx].on) {
-    rr->real[real_idx].on = 2;
-    rr->real[real_idx].id = bp->ip.ap.str.id;
+  } else if (!rr->real[real_idx].on && ring_gt(bp->ip.ap.fmt.content.clear.id, rr->content_id)) {
+    rr->real[real_idx].on = 1;
+    rr->real[real_idx].id = bp->ip.ap.fmt.content.clear.id;
     rr->real[real_idx].idx = real_idx;
     rr->real[real_idx].link_fd = fdinfo->fd;
     rr->real[real_idx].algo = app_ctx;
     mv_buffer_rtoa(app_ctx, fdinfo, &rr->real[real_idx].idx);
-
-    // 5. We register a timer for this packet to create a reactivation window for broken links
-    set_timeout(ctx, rr->mjit + 1, &rr->real[real_idx], expired_late);
-
-    //printf("%d is added to real as %d\n", bp->ip.ap.str.id, idx_real);
   } else {
-    fprintf(stdout, "Packet %d already received (current: %d)\n", bp->ip.ap.str.id, rr->recv_id);
-    mv_buffer_wtof (app_ctx, fdinfo);
+    if (ctx->verbose) fprintf(stdout, "Packet %d already received (current: %d)\n", bp->ip.ap.fmt.content.clear.id, rr->content_id);
+    mv_buffer_rtof (app_ctx, fdinfo);
   }
-
 }
 
-void rr_deliver(struct evt_core_ctx* ctx, struct evt_core_fdinfo* fdinfo, struct deferred_pkt* dp) {
+void rr_deliver(struct evt_core_ctx* ctx, struct algo_ctx* app_ctx, struct queued_pkt* dp) {
   struct evt_core_fdinfo *to_fdinfo = NULL;
-  struct algo_ctx* app_ctx = fdinfo->cat->app_ctx;
   struct rr_ctx* rr = app_ctx->misc;
   char url[255];
 
   // 1. Marked the packet as handled
-  dp->on--;
+  dp->on = 0;
 
   // 2. Get the buffer
   struct buffer_packet* bp = get_app_buffer (app_ctx, &dp->idx);
+  assert(bp->ip.ap.headers.cmd == CMD_CLEAR);
 
   // 3. We update our cursor
-  rr->recv_id = bp->ip.ap.str.id;
+  rr->content_id = bp->ip.ap.fmt.content.clear.id;
 
   // 4. Find its target
-  sprintf(url, "udp:write:127.0.0.1:%d", bp->ip.ap.str.port);
+  sprintf(url, "udp:write:127.0.0.1:%d", bp->ip.ap.fmt.content.clear.port);
   to_fdinfo = evt_core_get_from_url (ctx, url);
   if (to_fdinfo == NULL) {
     fprintf(stderr, "No fd for URL %s in udp:write for tcp-read. Dropping packet :( \n", url);
@@ -166,6 +110,54 @@ void rr_deliver(struct evt_core_ctx* ctx, struct evt_core_fdinfo* fdinfo, struct
   main_on_udp_write(ctx, to_fdinfo);
 }
 
+void rr_pkt_manage_links(struct evt_core_ctx* ctx, struct evt_core_fdinfo* fdinfo, struct buffer_packet* bp) {
+  struct algo_ctx* app_ctx = fdinfo->cat->app_ctx;
+  struct rr_ctx* rr = app_ctx->misc;
+
+  assert(bp->ip.ap.headers.cmd == CMD_HEALTH);
+
+  // 1. Health packet was received too late, dropping it
+  if (ring_le(bp->ip.ap.fmt.content.health.id, rr->health_id_late)) goto release;
+
+  // 2. Reactivate link if deactivated
+  char buffer[16];
+  url_get_port (buffer, fdinfo->url);
+  int link_num = atoi(buffer) - 7500; // @FIXME Hardcoded
+  if (!(rr->remote_links & (1 << link_num))) {
+    printf("Activate link=%d | ", link_num);
+    rr->remote_links |= 1 << link_num; // Make sure that the link is marked as working
+    show_link_availability (rr);
+  }
+
+  // 3. Update RR structure if its the greatest health_id we received
+  if (ring_gt(bp->ip.ap.fmt.content.health.id, rr->health_id)) {
+    // 3.1. Update current health id
+    rr->health_id = bp->ip.ap.fmt.content.health.id;
+
+    // 3.2. Update my links I can use thanks to target feedback
+    if (bp->ip.ap.fmt.content.health.bitfield != rr->my_links) {
+      rr->my_links = bp->ip.ap.fmt.content.health.bitfield;
+      printf("Update my links | ");
+      show_link_availability (rr);
+    }
+  }
+
+  // 4. Set callback to close this health packet window
+  int64_t timeout = rr->mjit - (int64_t) bp->ip.ap.fmt.content.health.deltat;
+  if (timeout <= 0) timeout = 0;
+  uint64_t idx = bp->ip.ap.fmt.content.health.id % PACKET_BUFFER_SIZE;
+
+  rr->wait[idx].health_id = bp->ip.ap.fmt.content.health.id;
+  rr->wait[idx].prevlink = bp->ip.ap.fmt.content.health.prevlink;
+  rr->wait[idx].min_blocked_pkt = bp->ip.ap.fmt.content.health.min_blocked_pkt;
+  rr->wait[idx].algo = app_ctx;
+
+  set_timeout (ctx, timeout, &rr->wait[idx], on_timeout_health);
+
+release:
+  mv_buffer_rtof(app_ctx, fdinfo);
+}
+
 void rr_pkt_unroll(struct evt_core_ctx* ctx, struct algo_ctx* app_ctx) {
   struct rr_ctx* rr = app_ctx->misc;
   struct evt_core_fdinfo* fdinfo = NULL;
@@ -173,16 +165,9 @@ void rr_pkt_unroll(struct evt_core_ctx* ctx, struct algo_ctx* app_ctx) {
 
   while(1) {
     //printf("Trying to deliver %d\n", rr->recv_id+1);
-    struct deferred_pkt* def = &rr->real[(rr->recv_id+1) % PACKET_BUFFER_SIZE];
+    struct queued_pkt* def = &rr->real[(rr->content_id+1) % PACKET_BUFFER_SIZE];
     if (!def->on) break;
-    fdinfo = evt_core_get_from_fd (ctx, def->link_fd);
-    if (fdinfo == NULL) {
-      fprintf(stderr, "An error occured as the link seems to be closed for the requested fd\n");
-      rr->recv_id++;
-      continue;
-    }
-
-    rr_deliver(ctx, fdinfo, def);
+    rr_deliver(ctx, app_ctx, def);
     //printf("Delivered %d\n", rr->recv_id);
   }
 }
@@ -193,11 +178,17 @@ int algo_rr_on_stream(struct evt_core_ctx* ctx, struct evt_core_fdinfo* fdinfo,
   struct algo_ctx* app_ctx = fdinfo->cat->app_ctx;
   struct rr_ctx* rr = app_ctx->misc;
 
-  // 1. Register packet in our queue
-  rr_pkt_register(ctx, fdinfo, bp);
+  if (bp->ip.ap.fmt.headers.cmd == CMD_CLEAR) {
+    if (ctx->verbose) printf("Received a CLEAR packet of size %d\n", bp->ip.ap.fmt.headers.size);
+    // 1. Register packet in our queue
+    rr_pkt_register(ctx, fdinfo, bp);
 
-  // 2. Process queue
-  rr_pkt_unroll (ctx, app_ctx);
+    // 2. Process queue
+    rr_pkt_unroll (ctx, app_ctx);
+  } else if (bp->ip.ap.fmt.headers.cmd == CMD_HEALTH) {
+    if (ctx->verbose) printf("Received a HEALTH packet of size %d\n", bp->ip.ap.fmt.headers.size);
+    rr_pkt_manage_links(ctx, fdinfo, bp);
+  }
 
   return 0;
 co_error:
@@ -221,28 +212,45 @@ int algo_rr_on_datagram(struct evt_core_ctx* ctx, struct evt_core_fdinfo* fdinfo
     exit(EXIT_FAILURE);
   }
 
+  // 2. Compute delta t
   secs = curr.tv_sec - rr->emit_time.tv_sec;
   nsecs = curr.tv_nsec - rr->emit_time.tv_nsec;
+  rr->emit_time = curr;
   mili_sec = secs * 1000 + nsecs / 1000000;
   if (mili_sec > rr->mjit) mili_sec = rr->mjit;
 
-  bp->ip.ap.str.id = rr->sent_id;
-  bp->ip.ap.str.flags = 0;
-  bp->ip.ap.str.deltat = mili_sec;
-  bp->ip.ap.str.bitfield = rr->remote_links;
-  bp->ip.ap.str.prevlink = rr->current_link;
+  // 3. Backup clear packet
+  struct buffer_packet clear_packet;
+  assert(bp->ip.ap.headers.cmd == CMD_CLEAR);
+  append_buffer (&clear_packet.ip.ap, 0, &bp->ip.ap);
 
+  // 4. Set health packet
+  bp->ip.ap.fmt.headers.cmd = CMD_HEALTH;
+  bp->ip.ap.fmt.headers.size = sizeof(bp->ip.ap.fmt.headers) + sizeof(bp->ip.ap.fmt.content.health);
+  bp->ip.ap.fmt.content.health.id = rr->sent_health_id;
+  bp->ip.ap.fmt.content.health.deltat = mili_sec;
+  bp->ip.ap.fmt.content.health.prevlink = rr->current_link;
+  bp->ip.ap.fmt.content.health.bitfield = rr->remote_links;
+  rr->sent_health_id++;
+
+  // 5. Append clear packet
+  clear_packet.ip.ap.fmt.content.clear.id = rr->sent_content_id;
+  rr->sent_content_id++;
+  bp->ip.ap.fmt.content.health.min_blocked_pkt = clear_packet.ip.ap.fmt.content.clear.id;
+  append_buffer (&bp->ip.ap, 1, &clear_packet.ip.ap);
+  bp->ap_count++;
+
+  // 6. Append redundancy if needed
   if (app_ctx->ap.redundant_data == 1) {
-    append_buffer(&bp->ip.ap, 1, &rr->prev_packet.ap); // We append previous packet
-    append_buffer(&rr->prev_packet.ap, 0, &bp->ip.ap); // We store current packet for next time
+    assert(ring_gt(bp->ip.ap.fmt.content.health.min_blocked_pkt, rr->prev_packet.ap.fmt.content.clear.id));
+    bp->ip.ap.fmt.content.health.min_blocked_pkt = rr->prev_packet.ap.fmt.content.clear.id;
+    append_buffer(&bp->ip.ap, 2, &rr->prev_packet.ap); // We append previous packet
+    append_buffer(&rr->prev_packet.ap, 0, &clear_packet.ip.ap); // We store current packet for next time
     bp->ap_count++;
   }
   //printf("Will send packet id=%d\n", bp->ip.ap.str.id);
 
-  rr->emit_time = curr;
-  rr->sent_id++;
-
-  // 2. Try to find someone to send it
+  // 7. Try to find someone to send it
   int max = 16;
   uint8_t sel_link = rr->current_link;
   while(max-- >= 0) {
@@ -251,13 +259,14 @@ int algo_rr_on_datagram(struct evt_core_ctx* ctx, struct evt_core_fdinfo* fdinfo
     to_fdinfo = evt_core_get_from_url (ctx, url);
     if (to_fdinfo == NULL) continue; // Missing link
     if (app_ctx->ap.is_waiting_bootstrap && !app_ctx->is_rdy) goto not_ready; // Some links are down
-    if (!app_ctx->ap.is_healing || rr->my_links & (1 << sel_link)) {
+    if (!app_ctx->ap.is_healing /* if healing deactivated */|| rr->my_links & (1 << sel_link) /* if link not down */ ) {
       rr->current_link = sel_link;
       mv_buffer_rtow (app_ctx, fdinfo, to_fdinfo);
       main_on_tcp_write(ctx, to_fdinfo);
       return 0;
     } else {
-      dup_buffer_tow(app_ctx, bp, to_fdinfo);
+      struct buffer_packet* dup_bp = dup_buffer_tow(app_ctx, bp, to_fdinfo);
+      dup_bp->ap_count = 1; // We want to send only health packet to help link recover... Bwarf same traffic on Tor...
       main_on_tcp_write(ctx, to_fdinfo);
     }
   }
@@ -273,39 +282,30 @@ co_error:
   exit(EXIT_FAILURE);
 }
 
-void expired_wait(struct evt_core_ctx* ctx, void* user) {
-  struct waited_pkt* pkt = user;
-  struct rr_ctx* rr = pkt->algo->misc;
+void on_timeout_health (struct evt_core_ctx* ctx, void* raw) {
+  struct timer_info* t = raw;
+  struct algo_ctx* app_ctx = t->algo;
+  struct rr_ctx* rr = app_ctx->misc;
 
-  // 1. Release lock
-  pkt->on = 0;
+  // 1. Update link recovery window if needed
+  if (ring_gt(t->health_id, rr->health_id_late)) rr->health_id_late = t->health_id;
 
-  // 2. We will not reactivate link for this packet
-  if (ring_lt(rr->recv_id_late, pkt->id)) rr->recv_id_late = pkt->id;
-
-  // 3. Stop if packet has been received and delivered
-  if (ring_le (pkt->id, rr->recv_id)) return;
-
-  printf("Timer reached for packet %d\n", pkt->id);
-
-  // 4. BLACKLIST LINK
-  printf("Blacklist link=%d | ", pkt->link_num);
-  rr->remote_links &= 0xff ^ 1 << pkt->link_num;
-  show_link_availability (rr);
-
-  // 5. Deliver following packets
-  while (ring_lt(rr->recv_id, pkt->id)) {
-    rr->recv_id++;
-    rr_pkt_unroll (ctx, pkt->algo);
+  // 2. Blacklist previous link if needed
+  uint16_t prev_health_id = (t->health_id - 1);
+  uint16_t prev_health_idx = prev_health_id % PACKET_BUFFER_SIZE;
+  struct timer_info* t_old = &rr->wait[prev_health_idx];
+  if (t_old->health_id != prev_health_id) {
+    printf("Blacklist link=%d | ", t->prevlink);
+    rr->remote_links &= 0xff ^ 1 << t->prevlink;
+    show_link_availability (rr);
   }
-}
 
-void expired_late(struct evt_core_ctx* ctx, void* user) {
-  struct deferred_pkt* pkt = user;
-  struct rr_ctx* rr = pkt->algo->misc;
-
-  pkt->on--;
-  if (ring_lt(rr->recv_id_late, pkt->id)) rr->recv_id_late = pkt->id;
+  // 3. Deliver blocked packets
+  //printf("t->min_blocked_pkt=%d, rr->content_id=%d\n", t->min_blocked_pkt, rr->content_id);
+  while (ring_gt(t->min_blocked_pkt, rr->content_id)) {
+    rr->content_id++;
+    rr_pkt_unroll (ctx, app_ctx);
+  }
 }
 
 int algo_rr_on_err(struct evt_core_ctx* ctx, struct evt_core_fdinfo* fdinfo) {
@@ -328,9 +328,12 @@ void algo_rr_init(struct evt_core_ctx* ctx, struct algo_ctx* app_ctx, struct alg
   rr->mjit = 200;
   rr->my_links = 0xff;
   rr->remote_links = 0xff;
-  rr->sent_id = 1;
-  rr->recv_id = 0;
-  rr->recv_id_late = 0;
+  rr->sent_health_id = 1;
+  rr->sent_content_id = 1;
+  rr->health_id = 0;
+  rr->health_id_late = 0;
+  rr->content_id = 0;
+  rr->current_link = 0;
   app_ctx->misc = rr;
   app_ctx->free_misc = algo_rr_free;
 
diff --git a/src/algo_utils.c b/src/algo_utils.c
index fc1fa4b..a85bd10 100644
--- a/src/algo_utils.c
+++ b/src/algo_utils.c
@@ -43,7 +43,7 @@ struct buffer_packet* get_read_buffer(struct algo_ctx *app_ctx, struct evt_core_
   struct buffer_packet* bp;
 
   // 1. Check if we don't have a buffer
-  bp = g_hash_table_lookup (app_ctx->used_buffer, &fdinfo->fd);
+  bp = fdinfo == NULL ? NULL : g_hash_table_lookup (app_ctx->used_buffer, &fdinfo->fd);
   if (bp != NULL) return bp;
 
   // 2. Get a new buffer otherwise
@@ -189,14 +189,14 @@ void mv_buffer_atof(struct algo_ctx* app_ctx, void* from) {
   g_queue_push_tail (app_ctx->free_buffer, bp);
 }
 
-void dup_buffer_tow(struct algo_ctx* app_ctx, struct buffer_packet* bp, struct evt_core_fdinfo* to) {
+struct buffer_packet* dup_buffer_tow(struct algo_ctx* app_ctx, struct buffer_packet* bp, struct evt_core_fdinfo* to) {
   GQueue* q;
 
   // 1. We get a free buffer
   struct buffer_packet* bp_dest = g_queue_pop_head(app_ctx->free_buffer);
   if (bp_dest == NULL) {
     debug_buffer(app_ctx, to);
-    return;
+    return NULL;
   }
 
   // 2. We duplicate the data
@@ -211,6 +211,7 @@ void dup_buffer_tow(struct algo_ctx* app_ctx, struct buffer_packet* bp, struct e
 
   // 4. We push the content to the appropriate destination
   g_queue_push_tail(q, bp_dest);
+  return bp_dest;
 }
 
 struct buffer_packet* get_app_buffer(struct algo_ctx *app_ctx, void* idx) {
@@ -238,9 +239,9 @@ void notify_read(struct evt_core_ctx* ctx, struct algo_ctx* app_ctx) {
 int append_buffer(union abstract_packet* dest, int pos, union abstract_packet* src) {
   char* target = &(dest->raw);
   while (pos-- > 0) {
-    target += dest->str.size;
+    target += ((union abstract_packet*) target)->fmt.headers.size;
   }
-  memcpy(target, src, src->str.size);
+  memcpy(target, src, src->fmt.headers.size);
   return 0;
 }
 
diff --git a/src/algo_utils.h b/src/algo_utils.h
index ce8d26a..76154de 100644
--- a/src/algo_utils.h
+++ b/src/algo_utils.h
@@ -51,7 +51,7 @@ void mv_buffer_wtof(struct algo_ctx* app_ctx, struct evt_core_fdinfo* from);
 void mv_buffer_rtoa(struct algo_ctx* app_ctx, struct evt_core_fdinfo* from, void* to);
 void mv_buffer_atow(struct algo_ctx* app_ctx, void* from, struct evt_core_fdinfo* to);
 void mv_buffer_atof(struct algo_ctx* app_ctx, void* from);
-void dup_buffer_tow(struct algo_ctx* app_ctx, struct buffer_packet* bp, struct evt_core_fdinfo* to);
+struct buffer_packet* dup_buffer_tow(struct algo_ctx* app_ctx, struct buffer_packet* bp, struct evt_core_fdinfo* to);
 
 int append_buffer(union abstract_packet* dest, int pos, union abstract_packet* src);
 
diff --git a/src/packet.c b/src/packet.c
index 6d520dd..518cb53 100644
--- a/src/packet.c
+++ b/src/packet.c
@@ -3,14 +3,14 @@
 size_t get_full_size(struct buffer_packet* bp) {
   union abstract_packet* ap = &bp->ip.ap;
   for (int i = 0; i < bp->ap_count; i++) {
-    ap = (union abstract_packet*)(&ap->raw + ap->str.size);
+    ap = (union abstract_packet*)(&ap->raw + ap->fmt.headers.size);
   }
   return &ap->raw - &bp->ip.ap.raw;
 }
 
 enum FD_STATE read_packet_from_tcp(int fd, struct buffer_packet* bp) {
   ssize_t nread;
-  size_t pkt_size_size = sizeof(bp->ip.ap.str.size);
+  size_t pkt_size_size = sizeof(bp->ip.ap.fmt.headers.size);
   if (bp->mode != BP_READING) return FDS_ERR;
 
   while (bp->aread < pkt_size_size) {
@@ -21,8 +21,8 @@ enum FD_STATE read_packet_from_tcp(int fd, struct buffer_packet* bp) {
     bp->aread += nread;
   }
 
-  while (bp->aread < bp->ip.ap.str.size) {
-    nread = read(fd, &(bp->ip.ap.raw) + bp->aread, bp->ip.ap.str.size - bp->aread);
+  while (bp->aread < bp->ip.ap.fmt.headers.size) {
+    nread = read(fd, &(bp->ip.ap.raw) + bp->aread, bp->ip.ap.fmt.headers.size - bp->aread);
     if (nread == 0) return FDS_AGAIN;
     if (nread == -1 && errno == EAGAIN) return FDS_AGAIN;
     if (nread == -1) return FDS_ERR;
@@ -46,7 +46,6 @@ enum FD_STATE write_packet_to_tcp(int fd, struct buffer_packet* bp) {
     if (nwrite == -1) return FDS_ERR;
     bp->awrite += nwrite;
   }
-
   bp->mode = BP_READING;
   bp->aread = 0;
   bp->ap_count = 0;
@@ -57,7 +56,8 @@ enum FD_STATE write_packet_to_tcp(int fd, struct buffer_packet* bp) {
 enum FD_STATE write_packet_to_udp(int fd, struct buffer_packet* bp, struct udp_target* udp_t) {
   ssize_t nwrite;
   size_t bytes_to_send;
-  size_t pkt_header_size = sizeof(bp->ip.ap.str) - sizeof(char);
+  assert(bp->ip.ap.headers.cmd == CMD_CLEAR);
+  size_t pkt_header_size = sizeof(bp->ip.ap.fmt.headers) + sizeof(bp->ip.ap.fmt.content.clear) - sizeof(char);
   struct sockaddr* addr = NULL;
   socklen_t addrlen = 0;
   if (udp_t->set) {
@@ -67,9 +67,9 @@ enum FD_STATE write_packet_to_udp(int fd, struct buffer_packet* bp, struct udp_t
 
   if (bp->mode != BP_WRITING) return FDS_ERR;
 
-  bytes_to_send = bp->ip.ap.str.size - pkt_header_size;
+  bytes_to_send = bp->ip.ap.fmt.headers.size - pkt_header_size;
   nwrite = sendto(fd,
-                  &(bp->ip.ap.str.payload),
+                  &(bp->ip.ap.fmt.content.clear.payload),
                   bytes_to_send,
                   0,
                   addr,
@@ -89,12 +89,12 @@ enum FD_STATE read_packet_from_udp (int fd, struct buffer_packet* bp, struct udp
   ssize_t nread;
   if (bp->mode != BP_READING) return FDS_ERR;
 
-  size_t pkt_header_size = sizeof(bp->ip.ap.str) - sizeof(char); // We remove the payload
+  size_t pkt_header_size = sizeof(bp->ip.ap.fmt.headers) + sizeof(bp->ip.ap.fmt.content.clear) - sizeof(char); // We remove the payload
   size_t udp_packet_size = sizeof(struct internet_packet) - pkt_header_size;
   socklen_t addrlen = sizeof(struct sockaddr_in);
 
   nread = recvfrom(fd,
-                   &(bp->ip.ap.str.payload),
+                   &(bp->ip.ap.fmt.content.clear.payload),
                    udp_packet_size,
                    MSG_TRUNC,
                    (struct sockaddr*)&udp_t->addr,
@@ -106,7 +106,8 @@ enum FD_STATE read_packet_from_udp (int fd, struct buffer_packet* bp, struct udp
 
   udp_t->set = 1;
   udp_t->addrlen = addrlen;
-  bp->ip.ap.str.size = nread + pkt_header_size;
+  bp->ip.ap.fmt.headers.size = nread + pkt_header_size;
+  bp->ip.ap.fmt.headers.cmd = CMD_CLEAR;
 
   bp->mode = BP_WRITING;
   bp->awrite = 0;
diff --git a/src/packet.h b/src/packet.h
index f07fd67..0c7b43d 100644
--- a/src/packet.h
+++ b/src/packet.h
@@ -1,4 +1,5 @@
 #pragma once
+#include <assert.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <unistd.h>
@@ -28,22 +29,35 @@ enum BP_MODE {
   BP_WRITING
 };
 
-enum PKT_FLAGS {
-  PKT_CONTROL = 1 << 0
+enum PKT_CMD {
+  CMD_HEALTH,
+  CMD_CLEAR,
+  CMD_XOR
 };
 
 union abstract_packet {
   char raw;
   struct {
-    uint16_t size;
-    uint16_t port;
-    uint16_t id;
-    uint8_t bitfield;
-    uint8_t prevlink;
-    uint16_t deltat;
-    uint8_t flags;
-    char payload;
-  } str;
+    struct {
+      uint16_t size;
+      enum PKT_CMD cmd;
+    } headers;
+
+    union {
+      struct {
+        uint16_t id;
+        uint8_t bitfield;
+        uint8_t prevlink;
+        uint16_t deltat;
+        uint16_t min_blocked_pkt;
+      } health;
+      struct {
+        uint16_t id;
+        uint16_t port;
+        char payload;
+      } clear;
+    } content;
+  } fmt;
 };
 
 struct internet_packet {
diff --git a/src/proxy.c b/src/proxy.c
index b392dee..60fe7c7 100644
--- a/src/proxy.c
+++ b/src/proxy.c
@@ -71,7 +71,7 @@ int main_on_udp_read(struct evt_core_ctx* ctx, struct evt_core_fdinfo* fdinfo) {
   if ((bp = get_read_buffer(app_ctx, fdinfo)) == NULL) return 1;
 
   // 2. Read packet from socket
-  bp->ip.ap.str.port = url_get_port_int (fdinfo->url);
+  bp->ip.ap.fmt.content.clear.port = url_get_port_int (fdinfo->url);
   read_res = read_packet_from_udp (fdinfo->fd, bp, fdinfo->other);
   if (read_res == FDS_ERR) goto co_error;
   if (read_res == FDS_AGAIN) return 1;