User guide

PCoIP Technology User Guide
21
Figure 8-4: Device Bandwidth Target: 30
Mbps
We now see:
• Device Bandwidth Target is set too high
• PCoIP Technology congestion management
still operates, but is not optimized
• Fairness is better than with no Target (0)
• Some dips down to 18 Mbps
Bandwidth Optimization
The simplified example above shows that PCoIP
System is optimized when the Device Bandwidth
Target is set to ensure fairness for all users.
Here the network link is 100 Mbps for four users,
so the fair Device Bandwidth Target is 25 Mbps
(100 Mbps / 4 users).
In the example, all four users were continually
active. This is not a realistic scenario, as even
extremely active users do not have constantly
changing displays (e.g. pause to study detail).
In actual use, it’s reasonable to assume that
each user has periods of low bandwidth usage.
Also, this example is a bit backward, as it started
with network capacity (100 Mbps) and then
found fair-usage settings. A better strategy is to
determine the bandwidth required to meet users’
expectations, and then work towards the
network capacity it requires.
Device Bandwidth Limit
Considerations
The example above has the Device Bandwidth
Limit set to 0 (none) to let the PCoIP Processors
manage bandwidth throttling. This is
recommended for most networks, unless the
administrator must limit bandwidth usage, for
example if:
• Legacy network equipment is unreliable when
fully utilized
• It is desired to put a cap on user bandwidth
usage
Constrained Network Effects
PCoIP Technology is designed to adjust
gracefully when there is not optimal bandwidth
available. However, during high network
congestion, some artifacts may become
noticeable, including:
• Image smearing/blocking
• Less-responsive user interface (e.g. slower
mouse and window movements)
It is recommended to set the Device Bandwidth
Limit at or below the limiting network link the
PCoIP Session data traverses. For example, if
the PCoIP Session data traverses a 100 Mbps
link (e.g. switch link to the desktop), the limit
should not exceed 100 Mbps.