Tieline Merlin PLUS User Manual page 72

72 Merlin PLUS WNET Manual v2.0
Feature
1 Lost Packets
2 Empty
Buffer)
3 Late Packets
4 FEC Packets
5 1 minute
6 10 minutes
Important Note: If the jitter buffer, FEC or the connection bit rate is changed, we
recommend assessing a minute of recent connection performance in preference to 10
minutes of historical connection performance. 10 minutes of data will include connection
settings which may no longer be relevant. 'Packet arrival history' is cleared when you hang
up a connection.
Following is a packet arrival analysis table with solutions for any noticeable packet loss statistics
displayed on the screen.
Packet Displays
Analysis
Loss Packets sent and
that failed to
arrive.
Empty Indicates how
often the jitter
buffer 'reservoir'
empties causing
loss of audio.
Late The number of
packets that
arrive late and
after audio play
out.
Description
Packets sent that failed to arrive
(Jitter Indicates how often the jitter buffer 'reservoir' empties causing loss of
audio
The number of packets that arrive late, i.e. after audio play out
Indicates the number of forward error correction (FEC) packets that
have been replaced if it is enabled in the codec
Statistics listed for the last minute of network activity
Statistics for the last 10 minutes of network activity
Possible Causes
·
LAN/WAN congestion
·
Unreliable ISPs
·
Unreliable networks
·
Inferior IP hardware
·
High number of
packets being lost or
arriving late
·
Signal dropouts
using cell-phone
networks
·
Renegotiation
causes the jitter
buffer reservoir to
empty
·
Network congestion
·
Jitter Buffer depth is
too low
Possible Solutions
·
Renegotiate connection bit rate
downwards
·
If link quality good add or increase
FEC as required
·
Assess ISPs QoS if very bad
performance
·
Once could be an anomaly –
assess lost & late packets
·
If many lost packets and network is
unreliable – renegotiate bit rate
and /or FEC down
·
If many late packets, increase jitter
buffer
·
Auto-jitter buffer will adjust
automatically
·
For manual jitter buffer settings
increase jitter buffer depth 50-100
ms & reassess (if only a few
packets arrive late over time, audio
repairs will be automatic and may
not require buffer changes).
© Tieline Pty. Ltd. 2017