diff --git a/src/vnet/tcp/tcp.h b/src/vnet/tcp/tcp.h
index 75046ae..955b2dd 100644
--- a/src/vnet/tcp/tcp.h
+++ b/src/vnet/tcp/tcp.h
@@ -140,7 +140,6 @@
   _(DEQ_PENDING, "Dequeue pending ")		\
   _(PSH_PENDING, "PSH pending")			\
   _(FINRCVD, "FIN received")			\
-  _(TRACK_BURST, "Track burst")			\
   _(ZERO_RWND_SENT, "Zero RWND sent")		\
 
 typedef enum tcp_connection_flag_bits_
@@ -256,6 +255,7 @@
 {
   TCP_BTS_IS_RXT = 1,
   TCP_BTS_IS_APP_LIMITED = 1 << 1,
+  TCP_BTS_IS_SACKED = 1 << 2,
 } __clib_packed tcp_bts_flags_t;
 
 typedef struct tcp_bt_sample_
@@ -821,7 +821,7 @@
  *
  * @param tc	tcp connection
  */
-void tcp_bt_track_tx (tcp_connection_t * tc);
+void tcp_bt_track_tx (tcp_connection_t * tc, u32 len);
 /**
  * Track a tcp retransmission
  *
@@ -852,6 +852,7 @@
  * @param bt	byte tracker
  */
 int tcp_bt_is_sane (tcp_byte_tracker_t * bt);
+u8 *format_tcp_bt (u8 * s, va_list * args);
 
 always_inline u32
 tcp_end_seq (tcp_header_t * th, u32 len)