docs: Update the statistics documentation.

doc/statistics.md

@@ -3,16 +3,16 @@ Introduction
 **Jitsi Videobridge implements reports for the following statistics:**
 
  * Number of threads used by the JVM.
- * Total and memory
- * CPU usage
- * Bitrate and packet rate
- * Loss rate
- * Number of audio and video channels
- * Number of conferences and participants
- * Estimated number of video streams
- * The size of the largest conference
- * The distribution of conference sizes
- * Aggregates of RTT and jitter across all users
+ * Current CPU and memory usage.
+ * Current bitrate, packet rate, and packet loss rate.
+ * Current number of audio and video channels, and conferences.
+ * Current estimated number of video streams.
+ * The size of the largest conference in progress.
+ * The distribution of the sizes of the conferences currently in progress.
+ * Aggregates of RTT and jitter across all users.
+ * The total number of created and completed conferences.
+ * The total duration of all completed conferences.
+ * The number of ICE sessions established over UDP or TCP.
 
 Implementation
 ==============
@@ -23,21 +23,24 @@ generated (in UTC).
  * **threads** - The number of Java threads that the video bridge is using.
  * **used_memory** - Total used memory on the machine (i.e. what 'free' would return) in megabytes (10^6 B).
  * **total_memory** - The total memory of the machine in megabytes.
- * **cpu_usage** - CPU usage for the machine. The value is between 0 and 1 and is the fraction of the last interval that the CPU spent in either user, nice, system or iowait state (what would appear in the 'cpu' line in 'top')
+ * **cpu_usage** - CPU usage for the machine. The value is between 0 and 1 and is the fraction of the last interval that the CPU spent in either user, nice, system or iowait state (what would appear in the 'cpu' line in 'top').
  * **bit_rate_download / bit_rate_upload** - the total incoming and outgoing (respectively) bitrate for the video bridge in kilobits per second.
  * **packet_rate_download / packet_rate_upload** - the total incoming and outgoing (respectively) packet rate for the video bridge in packets per second.
  * **loss_rate_download** - The fraction of lost incoming RTP packets. This is based on RTP sequence numbers and is relatively accurate.
  * **loss_rate_upload** - The fraction of lost outgoing RTP packets. This is based on incoming RTCP Receiver Reports, and an attempt to subtract the fraction of packets that were not sent (i.e. were lost before they reached the bridge). Further, this is averaged over all streams of all users as opposed to all packets, so it is not correctly weighted. This is not accurate, but may be a useful metric nonetheless.
  * **rtp_loss** - Deprecated. The sum of **loss_rate_download** and **loss_rate_upload**.
  * **jitter_aggregate** - Experimental. An average value (in milliseconds) of the jitter calculated for incoming and outgoing streams. This hasn't been tested and it is currently not known whether the values are correct or not.
  * **rtt_aggregate** - An average value (in milliseconds) of the RTT across all streams.
- * **largest_conference** - The number of participants in the largest conference hosted on the bridge.
+ * **largest_conference** - The number of participants in the largest conference currently hosted on the bridge.
  * **conference_sizes** - The distribution of conference sizes hosted on the bridge. It is an array of integers of size 15, and the value at (zero-based) index *i* is the number of conferences with *i* participants. The last element (index 14) also includes conferences with more than 14 participants.
- * **audiochannels** - Number of audio channels
- * **videochannels** - Number of video channels
- * **conferences** - Number of conferences
- * **participants** - Number of participants
- * **videostreams** - Number of video streams, there can be more than one per channel
+ * **audiochannels** - The current number of audio channels.
+ * **videochannels** - The current number of video channels.
+ * **conferences** - The current number of conferences.
+ * **participants** - The current number of participants.
+ * **videostreams** - An estimation of the number of current video streams forwarded by the bridge.
+ * **total_udp_connections / total_tcp_connections** - The total number of ICE sessions established over UDP or TCP.
+ * **total_conference_seconds** - The sum of the lengths of all completed conferences, in seconds.
+ * **total_conferences_created** - The total number of conferences created on the bridge.
 
 If Jitsi Videobridge is using XMPP it sends the statistics reports by COLIBRI
 protocol or by PubSub (XEP-0060).