Redirecting USB over RDP protocol - potential difficulties
You can use native operating system capabilities to redirect USB devices over RDP but you may run into difficulties. Certain devices work better than others because of certain issues such as bandwidth and network latency.
An example can be seen with USB devices that need consistently high throughput. Latency may impact their functionality in a VDI session. Another problem can come up with USB 3.0 devices attempting to use a USB 2.0 port on the client.
When sharing USB devices over RDP, an IT team needs to keep in mind the performance requirements of the peripheral equipment.
Factors to consider when sharing USB over RDP
- The state of the network is crucial when using USB audio devices. Unreliable networks are not recommended for these devices, as they need high throughput even when idle.
- Webcams are not supported when forwarding USB over remote desktop due to high bandwidth requirements that usually exceed 60 Mbps.
- The performance of USB scanners is directly related to the network’s state and scans may take longer than anticipated.
- WANs can pose latency and reliability issues that impact the performance of USB devices. An example of the problem is illustrated when reading a large file across the WAN. Each read request demands three two-way transfers between the remote desktop and a device. A small difference in network latency can be compounded over multiple requests to cause substantial performance degradation.
- Performance can be impacted by the file structure used on large USB disks. These can take a considerable amount of time to be recognized in an RDP session after being connected for the first time. Unreliable network links result in multiple retries which reduces performance. Using NTFS instead of FAT as the underlying filesystem can speed up connection time.
- USB CD/DVD readers, scanners, and touch devices also exhibit problems when used on a WAN with latency issues.