Using PCoIP® Zero Clients with PCoIP Host Cards
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Setting the Device Bandwidth Target is the preferred method for managing bandwidth utilization on a shared
network because it still allows individual remote sessions to exploit all available bandwidth when the network is
not congested. In contrast, the Device Bandwidth Limit (described in Section 3.1.3) is a hard limit on bandwidth
utilization that will restrict the user experience even if no other trac is on the network.
3.1.2 Device Bandwidth Floor
The Device Bandwidth Floor specifies the minimum bandwidth that a remote session will consume when
congestion is present and bandwidth is required. Bandwidth utilization will drop below the floor when
bandwidth is not required (e.g., when the display is static).
This setting is intended for use in networks where persistent packet loss (Section 3.4) or packet reordering
(Section 3.5) cannot be eliminated. The best solution is to identify and fix the source of packet loss or packet
reordering in the network. While the network problem is being resolved, the PCoIP session experience can be
improved by using the Device Bandwidth Floor setting.
The default setting of 0 (zero) uses the default bandwidth floor (currently 1,000 kbps for 1:1 sessions).
Setting this to a non-zero value (> 1,000 kbps) will give remote users a better user experience by increasing
the minimum bandwidth the remote session will attempt to use in the presence of persistent packet loss.
However, this should be done in consultation with users and only if network bandwidth and demands are
well understood, because the higher this value is set, the less flexibility the PCoIP protocol has to adjust to
real network congestion. As a result, setting this value too high can result in a significantly degraded overall
experience if the network becomes oversubscribed, that is, the combined trac from all remote sessions
exceeds the bandwidth that the network can provide).
Once the network packet loss/reordering issue in the network has been resolved, reset the Device Bandwidth
Floor to 0 (zero).
3.1.3 Device Bandwidth Limit
The Device Bandwidth Limit defines the maximum peak bandwidth that a PCoIP session will consume and is
provided primarily for testing purposes, but can sometimes be useful in production deployments.
• The Device Bandwidth Limit setting on the host card limits bandwidth on trac from the host to the client
(primarily display data). This represents the vast majority of bandwidth utilization.
• The Device Bandwidth Limit setting on the client limits bandwidth on trac from the client to the host
(e.g., USB or microphone audio data).
• The bandwidth limit range is 1,000 to 220,000 kbps.
The recommended setting for the Device Bandwidth Limit is 0 (zero), which configures the PCoIP processor to
adjust the bandwidth solely based on network congestion with no limit. The processor will maximize the user
experience based on the bandwidth available at any given moment. However, a non-zero setting (> 1,000 kbps)
may be appropriate in situations where there are network constraints, such as:
• If there is a known network bandwidth constraint between the PCoIP host and client, set the Device
Bandwidth Limit to approximately 90% of this bandwidth limit.
– For example, if the PCoIP host is on a 100 Mbps network but the zero client is connected on a 6 Mbps
ADSL link, set the Device Bandwidth Limit to approximately 90% x 6 Mbps = 5,400 kbps.
• If you are experiencing congestion and packet loss on a network being shared between PCoIP sessions and
other types of network trac, consider setting the Device Bandwidth Limit to constrain aggregate PCoIP
session bandwidth.
– For example, if you have four similar users (similar application demands and priority) sharing a 6 Mbps
link with other network traffic, setting the Device Bandwidth Limit to 70% of the link bandwidth (70% x
6,000 kbps = 4,200 kbps) will help reduce congestion on the network.
