Transcript
Research Report of Desktop Email:
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Cloud Experience
Huawei official website: http://www.huawei.com/en/ilab
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Released by Huawei iLab, February 2017
Desktop cloud service allows users to access virtual desktops deployed on the cloud through the network using terminals such as thin clients (TC), pads, laptops, and mobile phones. In the cloud era, the main values of desktop cloud for users include centralized data management and control, high security, mobile office, and on-demand dynamic resource configuration. As one of the ways to access the cloud world, desktop cloud is changing the mode that people work. After preliminarily experiencing the desktop cloud service provided by two vendors, Huawei iLab presented the following key findings: 1. There is a high network latency requirement to achieve quick login, smooth application of Microsoft PowerPoint (PPT), and clear voice communication of desktop cloud.
Proper experience with round trip time (RTT) less than 40 ms: acceptable login speed (less than 10s); smooth response of PPT, clear images and no obvious delay; good voice experience with a high mean opinion score (MOS). Degraded performance with RTT up to 60 ms: delay occurs in PPT page flipping; when the RTT increases to 100 ms, the login speed decreases to about 17.8s; when the RTT increases to 160 ms, there are obvious noises and delay in voice.
4. If desktop cloud is deployed in households, a 25 Mbit/s bandwidth in the home broadband package must be reserved for desktop cloud. In the future, a 100 Mbit/s bandwidth will be required for home broadband to support multiple devices in a family: 37.5 Mbit/s for a single-screen 4K TV, 7.5 Mbit/s for a 1080p mobile phone, 7.5 Mbit/s for a single-screen tablet, and 10.5 to 25 Mbit/s for a single-screen desktop cloud. 5. Although the traffic required by a single user is low, desktop cloud offices in enterprise campus require large bandwidths because of the high user concurrency. A 10.5 Mbit/s bandwidth should be reserved per user for a pure office working environment and a 25 Mbit/s bandwidth should be reserved per user if video streaming is required.
1. Differences Between Desktop Cloud and Traditional PCs Traditional PC
Desktop cloud
Local storage, computing, and applications are migrated to the cloud data center.
2. Desktop cloud applied in office work requires no large traffic, but good experience requires a high bandwidth. Superior experience requires over 10.5 Mbit/s bandwidth to ensure quick login, smooth application of PPT, high-fidelity images, and good voice quality. Login delay occurs when the bandwidth is less than 5 Mbit/s. PPT response delay occurs when the bandwidth is less than 10.5 Mbit/s. 3. Videos on desktop cloud require larger bandwidths compared with traditional playing modes. To improve the experience of desktop cloud videos, efforts must be made to improve both the video processing technology and bandwidth. Playing a local 720p video on the desktop cloud requires a bandwidth of about 10 to 25 Mbit/s. It requires only less than half of the bandwidth required on traditional terminals (about 4.8 Mbit/s) than that on the desktop cloud.
01
PC becomes a thin client.
Mobile phone
PC
Thin client
Laptop Tablet
2. Desktop Cloud System Users transmit commands to the desktop cloud virtual machine (VM) through the network using a mouse and keyboard. After the response, desktop cloud VM encapsulates application data through VDI protocol, transmits it to the client through the network and displays it on the client screen. Desktop cloud server is deployed in the data center. 02
LAN Thin client Mirrored packet capturing
Office area (testing area)
APP OS VM
WAN
4. Interactive Process Analysis of Typical Desktop Cloud Scenarios
Web
Service side of the VDI protocol
Client side of the VDI protocol
Email
Desktop Egress Access cloud router Aggregation Server
Video
Data center
The preliminary experience this time involves user login, PPT application, voice communication, and video experience. These four scenarios can best represent the keyboard and mouse interaction technology, graphics display technology, voice processing technology, and video display technology of the desktop cloud protocol.
IM
Desktop cloud login
3. Experience Elements of Desktop Cloud Services Operating system interface
Subjective experience System operation experience First response time
Experience elements User login PPT startup
Instant messaging (IM) startup
Player startup
Start and shut down
Interactive experience
Sleep and wake up
Browsing
Calling and answering
Playing
Startup process experience of the applications
Application startup
Editing
Talking
End
Mouse interaction
Playing
First response time, interactive experience, and response speed
Keyboard interaction
2D image display
Unnatural images
End
Natural images System audio
APP operation experience
Voice
Display quality, view experience, and
Video display
Local videos
interactive experience
3D image display
Online videos
Desktop cloud logout
VoIP
4.1 Desktop Cloud Login
Peripheral redirection
03
End
Log in to a desktop cloud is actually the login to a desktop cloud VM at the remote end of the network. The login process is displayed on the TC terminal through a network extension. 04
Traffic models during the login process:
Enter the cloud address and access the WI address.
The interaction traffic is about 3.9 MB for the entire login process. The peak bandwidth is required when the Windows main interface is displayed. At this time, the rate is 7.8 Mbit/s and the traffic required by mouse interaction is about 0.01 MB.
When the bandwidth is less than 5 Mbit/s, the login time obviously increases and a black screen occurs during the login process.
Enter the user name and password.
The relationship between login experience and bandwidth Smooth
4.5 4 3.5 3 Experience 2.5 2 1.5 1 0.5 0
Select a desktop cloud VM.
Slowdown
3.5 Portal site of a virtual desktop
7.74 Mbit/s
When the RTT increases to 100 ms, the login duration increases to about 17.8s and the subjective experience starts to degrade.
Experience
4.5 4 3.5 3 2.5 2 1.5 1 0.5 0
5
5.5
7.80 Mbit/s Uplink traffic Downlink traffic
5.08 Mbit/s
Smooth 1.98 Mbit/s
Slowdown Entering the login interface
60
05
4.5 Bandwidth (Mbit/s)
bit/s
When the RTT is less than 70 ms, the login duration is shorter than 10s, and such a speed is acceptable during the experience.
The relationship between login experience and RTT
4
70
80 90 RTT (ms)
100
110
Entering the selection interface of a VM
During the login process and displaying PPT after the login
Clicking the taskbar, displaying the desktop, and the desktop displaying process
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4.2 PPT Application in Desktop Cloud bit/s
PPT is opened in the desktop cloud VM and then projected to the client through desktop transmission protocol.
22.65 Mbit/s Total traffic
When the RTT is less than 40 ms, the images are clear, there is no sense of delay, and the page flipping responses within 1s.
Uplink traffic
When the RTT increases to 60 ms, the page flipping response takes about 3s with a sense of delay.
14.59 Mbit/s 12.16 Mbit/s
The relationship between PPT experience and RTT 4.5
9.97 Mbit/s
Smooth
4 3.5 3
0.69 Mbit/s
2.5 Experience
2 1.5 1
Slowdown
0.5 0
35
40
45
50 RTT (ms)
55
60
65
Traffic models during the PPT processing:
When the bandwidth is less than 10.5 Mbit/s, obvious delay occurs during the PPT page flipping and user experience degrades.
The relationship between PPT experience and bandwidth Smooth
4 3.5 3 Experience 2.5 2 Delay
1.5 1 0.5 0 7.5
07
8
8.5 9 9.5 Bandwidth (Mbit/s)
Switching Screen the browse scrolling mode to the normal view mode
Clicking any page
Full-screen auto-playing
Closing the PPT
4.3 Voice Communication in Desktop Cloud
The peak occurs at the moment of a page refresh with the value from 0.69 Mbit/s to 22.65 Mbit/s, and the actual value varies with the complexity of the PPT contents.
4.5
Opening the PPT
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The evaluation is made with reference to the ITU-T perceptual evaluation of speech quality (PESQ).
Level
MOS Value
Customer Satisfaction
Excellent
4.0–5.0
Very good, with clear voices
Good
3.5–4.0
Fairly clear voices, but with a little noise
Medium
3.0–3.5
Not so good, but can still communicate
Inferior
1.5–3.0
Bearable, but cannot hear clearly
Bad
0–1.5
Very bad, and cannot hear
10.5
08
For a 3-minute voice call between two users, the relationship between voice quality and network latency is shown in the figure below.
Desktop cloud video decoding involves two key technologies: server-side decoding and client-side decoding (multimedia redirection). Server-side decoding takes video images as parts of desktop images and projects them to the client through the VDI protocol. The following sections analyze the network bandwidth requirements of server-side decoding.
The relationship between voice communication and RTT 4 Good (3.5)
3.5
3 2.5 Experience (MOS)
4.4 Processing Mechanism of Desktop Cloud Videos Results in Larger Bandwidth Requirements
2 1.5
Bad (1.5)
The video source resolution, content complexity, and content change per frame will affect the bandwidth requirement from the server to the client. The tested bandwidth data is related to the selected video source. 4.4.1 High Demand for Bandwidth When Streaming Both Local and Online Videos on Desktop Cloud
1 0.5 0 80
90
100
110
120 130 RTT (ms)
140
150
160
170
(1) Different from traditional PCs, desktop cloud requires traffic for playing local videos. Local video streaming with various players on desktop cloud (resolution: 1280x720, bit rate: 1.9 Mbit/s):
Traffic characteristics of voice communication: Voice communication consumes a little traffic: the uplink traffic is about 1.3 MB; and the downlink traffic is about 1.6 MB. The peak rate occurs at the moment of answering or hanging up. bit/s
The desktop cloud client consumes higher bandwidth while adopting
MPEG2 coding than adopting the H.264 coding. Using a traditional way to play a 720p video will require about 4.8 Mbit/s
bandwidth, whereas using desktop cloud will require 10 to 25 Mbit/s bandwidth, which is more than twice of that in the traditional way.
1.64 Mbit/s 30 25 Total traffic Total voice traffic Uplink voice traffic
Bandwidth comparison of full-screen local video streaming with various players on desktop cloud 25
20 Bandwidth (Mbit/s) 15
14
12
10 0.51 Mbit/s
10
5 0
0.2 Mbit/s
IM voice answering
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During a voice call (speak in turn, keep silent, and speak loudly)
Storm Codec (MPEG2) Voice hanging up
Storm Codec (H.264)
QQ Player (MPEG2)
QQ Player (H.264)
Local video resolution: 1280x720, bit rate: 1.9 Mbit/s Display resolution: 1920x1080
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(2) Different from traditional PCs, desktop cloud also requires higher bandwidth for online videos.
4.4.2 Comparison of Network Bandwidths for Video Streaming with Mainstream Desktop Cloud Protocols
Resolution: 736x414, bit rate: 0.9 Mbit/s: Using a traditional way to play the online video requires about 2 Mbit/s bandwidth, while using desktop cloud requires about 6 Mbit/s bandwidth, which is about 3 times of that in the traditional way.
Bandwidth comparison of full-screen online video streaming with desktop cloud and traditional PC 7
6 6
Desktop Cloud Protocol
Requirement of Network Bandwidth
ICA/HDX
Fairly low
PCoIP
High
HDP
Fairly low
RDP/RemoteFX
High
SRAP
Medium
SPICE
Medium
Source of part of the data: H3C focus: desktop connection protocol parsing
5
Bandwidth (Mbit/s)
4
4.4.3 Suggestions for Improving Video Experience through Desktop Cloud Technologies
3 2
Improve video encoding performance on the client.
Optimize the H.264 encoding parameters of the current desktop cloud.
Use the H.265 encoding technology to replace H.264.
Standardize redirection APIs for client-side decoding.
2 1 0
Using PC
Using desktop cloud
Online videos: 736x414 resolution and 0.9 Mbit/s bit rate Display resolution: 1920x1080
4.5 Bandwidth Requirement for Good Desktop Cloud Experience Bandwidth requirement of good user experience on desktop cloud
(3) Why is a higher bandwidth required for playing videos on desktop cloud?
VDI protocol policy H.264 encoding parameters
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• Quality/Bandwidth comes first. • Average bandwidth results in average quality, and the lowest quality results in peak bandwidth. • The ultra-fast mode has the features of simple compression encoding and low CPU consumption. • The VM density and real-time processing are ensured.
Bandwidth (Mbit/s)
No B-frame encoding
Desktop cloud has a higher requirement for real-time transmission than the traditional way when playing videos. Desktop cloud cannot respond to users' operations immediately because the B-frame encoding needs an extra 30 ms.
30
25
25 20 14
15 10
10.5
11
12
10 6
5
5 0 Login
PPT
Desktop sharing
Local videos Local videos Local videos in Storm in QQ Player in Storm Codec (MPEG2) Codec (MPEG2) (H.264)
Local videos in QQ Player (H.264)
Online videos
Local videos: 1280x720 resolution and1.9 Mbit/s bit rate Online videos: 736x414 resolution and 0.9 Mbit/s bit rate
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5. Desktop Cloud Service Requirements on Campus Networks
6. Desktop Cloud Brings Bright Future to Home Broadband 1. Desktop cloud brings value-added broadband packages to hundreds and thousands of households.
Client Access switch
Aggregation Core switch router
DC egress router
Core router Backbone network
Building equipment room of the region
Desktop cloud data center
Central equipment room of the region
The above figure shows a large enterprise user sharing a desktop cloud data center. According to the assessment data, it can be inferred that in order to provide good user experience, the desktop cloud should: 1. The link bandwidth between the aggregation switch and core router should be above 20 Gbit/s. If there are 500 desktop cloud users working or watching standard definition (SD) videos at the same time, the average link bandwidth should be 10–25 Mbit/s and the port rate should be 5–20 GE or higher to ensure good user experience. If high-definition (HD) videos are to be watched, or working or data backups are involved in the future, the link bandwidth should be at least 20 Gbit/s. 2. It is advised that the egress rate of the data center network is over 100GE. If the data center (DC) is planned for 10,000 desktop cloud users to work or watch SD videos at the same time, the per-user link bandwidth should be 10–25 Mbit/s and the DC egress rate should reach 100GE to ensure good user experience. 3. The network adapter rate of the desktop cloud server should be at least 10GE. If there are 25 users connecting to the desktop cloud server, the per-user bandwidth should be 10–25 Mbit/s to ensure good user experience. If they are working or watching 720p videos at the same time, the network adapter rate should be greater than 625 Mbit/s (25 x 25 Mbit/s). If users watch 4K videos in the future, the egress rate should be no lower than 10GE.
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Desktop cloud walks into home offices, and together with mobile phones and TVs, the bandwidth required by the multi-screen video streaming is about 100 Mbit/s. 2. The thin client-integrated ONUs or STBs will be available in hundreds and thousands of households. 3. Thin clients with the Wi-Fi function will make the desktop cloud more flexible and convenient in enterprise offices or households.
Appendixes: 1. Experience site: XXX campus in Shenzhen 2. Desktop cloud conditions for the evaluation: Client Parameter CPU Clock Speed
Desktop Cloud System Parameter
System
CPU Clock Speed
Windows (64-bit)
2.60 GHz
Memory Storage Specification
2.41 GHz
1.87 GB
7.37 GB
Memory Storage Specification 7.99 GB
280 GB
3. Video sources for the evaluation are as follows:
Video Source
File Length File Size (MB) (Minute)
Bit Rate (Mbit/s)
Resolution
Frame Rate (fps)
splitin4k720p.mp4
3
42
1.9
1280x720
24
Online video
3.77
27.4
0.9
736x414
25
14
