From Martin Mathieson:

 I've written this patch to use the 'Delay since last SR' (DLSR) field found
in SR reports to calculate and report roundtrip-propagation delays.  This is
described in rfc 3550, section 6.4.1, inside the description of DLSR.

Only the endpoint can compute the end-end roundtrip delay, and only they
know exactly when the report is received and can compare it with the 'Last
SR timestamp' (LSR) that they set.  This patch instead takes the difference
between the capture times of the 2 reports and subtracts the DLSR (the LSR
is checked in case the SR it's referring to wasn't captured).  The time
difference represents a roundtrip network delay between the point of capture
and the sender of the SR containing the DLSR.


svn path=/trunk/; revision=11998

1 files changed, 19 insertions, 3 deletions

diff --git a/epan/dissectors/packet-rtcp.h b/epan/dissectors/packet-rtcp.h
index b997ab6738..096d24b39a 100644
--- a/epan/dissectors/packet-rtcp.h
+++ b/epan/dissectors/packet-rtcp.h
@@ -27,12 +27,28 @@
  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  */
 
-/* Info to save in RTCP conversation / packet-info */
+/* Info to save in RTCP conversation / packet-info.
+   Note that this structure applies to the destination end of
+   an RTP session */
 #define MAX_RTCP_SETUP_METHOD_SIZE 8
 struct _rtcp_conversation_info
 {
-	gchar   method[MAX_RTCP_SETUP_METHOD_SIZE];
-	guint32 frame_number;
+    /* Setup info is relevant to traffic whose dest is the conversation address */
+    guchar  setup_method_set;
+    gchar   setup_method[MAX_RTCP_SETUP_METHOD_SIZE];
+    guint32 setup_frame_number;
+
+    /* Info used for roundtrip calculations */
+    guchar  last_received_set;
+    guint32 last_received_frame_number;
+    guint32 last_received_time_secs;
+    guint32 last_received_time_usecs;
+    guint32 last_received_ts;
+
+    /* Stored result of calculation (ms) */
+    guchar  calculated_delay_set;
+    guint32 calculated_delay_used_frame;
+    guint32 calculated_delay;
 };