Dell Precision R5400 Remote Access Device: Task-Based User Guide  - Page 21

PCoIP Technology User Guide (Vol I) 9 Latency Considerations With any network, there are latency effects to be addressed. The following are latency effect considerations for PCoIP Technology deployments: • Latency effects are subjective and affect response (e.g. mouse movement) • Latency due to length of physical medium (i.e. speed of light of copper/fiber) and switch hops • Additional latency due to OS (e.g. 40-50 ms for Windows) The table below outlines latency effects examples based on critical user evaluation. User tolerance levels for latency vary widely. Table 2: Latency Network Latency Approx. Distance1 0-30 ms Campus/Metro/ Inter-city (0-1500 km) 40-60 ms Inter-city/Intracountry (1500-2500 km) 60-100 ms Intra-country/ Intercontinent (2500-5000 km) > 100 ms Inter-continent/ Overseas (> 5000 km) Example Observations2 Perception free to average user Minimal latency perceived, e.g. 'heavier' than usual mouse pointer/windows, but very usable Sluggish mouse and windows Some audio/ video dropouts Slow mouse and windows Audio/video dropouts Notes: 1. High bandwidth, low error network 2. Examples given are based on subjective critical analysis Note: As with bandwidth considerations, these latency observations are subjective and biased towards a perception free experience. Administrators must study use case(s) typical for their deployment and adjust user expectations accordingly. TER0806003 Issue 1 Desired Network Attributes The desired network attributes to minimize latency effects are: • High bandwidth • Low error rate • Minimized data path/network hops Networks with less desirable network attributes will result in decreased performance, i.e. decreased mouse and display responsiveness. USB Latency Performance USB performance can vary over latency for the various transfer types: • Isochronous - may notice delay or loss of data (e.g. video data lost on a webcam) • Interrupt - may delay device response (e.g. slow keystrokes from keyboard) • Bulk - may notice slower data transfer (e.g. slower USB FLASH drive) Minimizing Latency Effects The following are suggestions for extreme long distances, non-enterprise networks or less than desirable networks to minimize latency effects: • Use graphically less demanding computer applications and set user expectations accordingly • For bandwidth constricted environments, configure Device Target Bandwidth and Device Bandwidth Limit parameters to limit bandwidth usage to minimum required (see Section 6 Bandwidth Considerations) • Configure Image settings to minimum image quality required (see Section 7 Imaging Considerations). © 2008 Teradici Corporation Page 21 of 25