diff --git a/src/algo_lightning.c b/src/algo_lightning.c
index 90e38c0..ea9fedc 100644
--- a/src/algo_lightning.c
+++ b/src/algo_lightning.c
@@ -200,7 +200,7 @@ int send_message(struct evt_core_ctx* ctx, struct buffer_packet* bp) {
   union abstract_packet *ap_buf = buffer_append_ap (bp_dup, &monit);
   uint8_t *links = &ap_buf->fmt.content.link_monitoring_lightning.prev_links;
   for (int i = 0; i < lightc->sent_past_links; i++) {
-    links[i] = lightc->prev_links[lightc->pkt_sent_id - (i + 1) % MAX_LINKS];
+    links[i] = lightc->prev_links[(lightc->pkt_sent_id - (i + 1)) % MAX_LINKS];
   }
 
   lightc->prev_links[lightc->pkt_sent_id % MAX_LINKS] = lightc->selected_link;
@@ -224,27 +224,35 @@ int algo_lightning_on_datagram(struct evt_core_ctx* ctx, struct evt_core_fdinfo*
   int64_t stats[MAX_LINKS];
   algo_lightning_update_stats(lightc, stats);
 
-  struct timespec now;
+  struct timespec now, temp_time;
   set_now(&now);
 
-  while (1) {
+  int protection = lightc->total_links;
+  while (protection-- > 0) {
     lightc->selected_link = (lightc->selected_link + 1) % lightc->total_links;
-    uint64_t cdelta = stats[lightc->selected_link];
+    int64_t cdelta = stats[lightc->selected_link];
 
     // OK link
-    if (cdelta >= 0 && cdelta < lightc->max_ooo) {
+    printf("cdelta=%ld\n", cdelta);
+    if (cdelta < lightc->max_ooo) {
       send_message (ctx, bp);
       break;
     }
 
     // Broken link that must be probed
-    if (elapsed_micros (&now, &lightc->last[lightc->selected_link]) >= lightc->sleep_duration) {
+    timespec_diff (&now, &lightc->last[lightc->selected_link], &temp_time);
+    uint64_t elapsed = timespec_get_unit(&temp_time, MILISEC);
+    if (elapsed >= lightc->sleep_duration) {
       send_message (ctx, bp);
       continue;
     }
 
     // Broken link probed recently
   }
+  if (protection <= 0) {
+    fprintf(stderr, "Schedule error\n");
+    exit(EXIT_FAILURE);
+  }
 
   mv_buffer_rtof (&app_ctx->br, fdinfo);
   return 0;