diff --git a/src/vnet/tcp/tcp.h b/src/vnet/tcp/tcp.h
index 9988069..361abe2 100644
--- a/src/vnet/tcp/tcp.h
+++ b/src/vnet/tcp/tcp.h
@@ -263,6 +263,8 @@
   f64 delivered_time;		/**< Delivered time when sample taken */
   f64 tx_time;			/**< Transmit time for the burst */
   f64 first_tx_time;		/**< Connection first tx time at tx */
+  u64 tx_in_flight;		/**< In flight at tx time */
+  u64 tx_lost;			/**< Lost at tx time */
   tcp_bts_flags_t flags;	/**< Sample flag */
 } tcp_bt_sample_t;
 
@@ -273,9 +275,12 @@
   f64 prior_time;		/**< Delivered time of sample used for rate */
   f64 interval_time;		/**< Time to ack the bytes delivered */
   f64 rtt_time;			/**< RTT for sample */
+  u64 tx_in_flight;		/**< In flight at (re)transmit time */
+  u64 tx_lost;			/**< Lost over interval */
   u32 delivered;		/**< Bytes delivered in interval_time */
   u32 acked_and_sacked;		/**< Bytes acked + sacked now */
-  u32 lost;			/**< Bytes lost now */
+  u32 last_lost;		/**< Bytes lost now */
+  u32 lost;			/**< Number of bytes lost over interval */
   tcp_bts_flags_t flags;	/**< Rate sample flags from bt sample */
 } tcp_rate_sample_t;
 
@@ -420,6 +425,7 @@
   u64 app_limited;		/**< Delivered when app-limited detected */
   f64 delivered_time;		/**< Time last bytes were acked */
   f64 first_tx_time;		/**< Send time for recently delivered/sent */
+  u64 lost;			/**< Total bytes lost */
   tcp_byte_tracker_t *bt;	/**< Tx byte tracker */
 
   tcp_errors_t errors;	/**< Soft connection errors */
diff --git a/src/vnet/tcp/tcp_bt.c b/src/vnet/tcp/tcp_bt.c
index b664944..e8dc5c9 100644
--- a/src/vnet/tcp/tcp_bt.c
+++ b/src/vnet/tcp/tcp_bt.c
@@ -275,6 +275,8 @@
   bts->tx_time = tcp_time_now_us (tc->c_thread_index);
   bts->first_tx_time = tc->first_tx_time;
   bts->flags |= tc->app_limited ? TCP_BTS_IS_APP_LIMITED : 0;
+  bts->tx_in_flight = tcp_flight_size (tc);
+  bts->tx_lost = tc->lost;
   return bts;
 }
 
@@ -475,6 +477,8 @@
   rs->interval_time = bts->tx_time - bts->first_tx_time;
   rs->rtt_time = tc->delivered_time - bts->tx_time;
   rs->flags = bts->flags;
+  rs->tx_in_flight = bts->tx_in_flight;
+  rs->tx_lost = bts->tx_lost;
   tc->first_tx_time = bts->tx_time;
 }
 
@@ -586,6 +590,8 @@
   if (PREDICT_FALSE (tc->flags & TCP_CONN_FINSNT))
     return;
 
+  tc->lost += tc->sack_sb.last_lost_bytes;
+
   delivered = tc->bytes_acked + tc->sack_sb.last_sacked_bytes;
   if (!delivered || tc->bt->head == TCP_BTS_INVALID_INDEX)
     return;
@@ -607,7 +613,8 @@
 				rs->interval_time);
   rs->delivered = tc->delivered - rs->prior_delivered;
   rs->acked_and_sacked = delivered;
-  rs->lost = tc->sack_sb.last_lost_bytes;
+  rs->last_lost = tc->sack_sb.last_lost_bytes;
+  rs->lost = tc->lost - rs->tx_lost;
 }
 
 void