Cisco Cisco WebEx Meeting Center WBS30 Libro blanco
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During a video-enabled WebEx meeting, a portion of the network bandwidth is consumed by the video bit streams
that are being transmitted and received. The actual bandwidth consumption can be affected by admin or user- level
settings and by network conditions.
The test used BlackBerry Bold 9700 (BB). The traffic was monitored with the Mobile Data Alerter software. For
iPhones and iPads, the testing team used the actual devices connected to a Mac and a traffic-monitoring tool to
monitor data usage. PC tests were run with Window clients. All measurements were captured locally with the Iris
Network Analyzer tool. The testing team also monitored the inbound and outbound HTTP traffic from the PCs and
other devices to the Cisco Collaboration Cloud. Measurements were captured from both the presenter’s machine
and the attendee’s machine. There was no significant difference in the bandwidth for data sharing; therefore tests
other devices to the Cisco Collaboration Cloud. Measurements were captured from both the presenter’s machine
and the attendee’s machine. There was no significant difference in the bandwidth for data sharing; therefore tests
related to data sharing assume both presenter and attendee traffic to be the same.
All measurement results are in kilobits per second (kbps), not kilobytes (KB). File sizes are measured in kilobytes
(KB). A byte is eight bits; a kilobyte is 1024 bytes. Eight bits multiplied by 1024 equals 8192 bits. Transmission
rates are also measured in kilobits per second (not kilobytes).
Measurement Scenarios for Mobile Clients
●
Idle: Baseline network traffic in a meeting
●
Presentation share: Presenter shares a PowerPoint presentation with graphics and animations
●
Desktop share and application share: Presenter shares a desktop, running a PowerPoint presentation with
30-second transitions
●
Internet phone (VoIP): Presenter and attendees have a conversation using PC microphones
Average Video Bandwidth Consumption
Table 7 gives the average bandwidth consumption for each of the video configurations.
Table 7.
Average Bandwidth Consumption
Session
HD
HQ-Active Video
Source
720p
180p
360p
Six thumbs at 90p
One 180p + six
thumbs at 90p
thumbs at 90p
Sender traffic (kbps)
1750-2380
330
911
-
-
Received traffic
1260-1820
245
635
313
482
These results are for video traffic only; add an average of 70 to 150 kbps for VoIP traffic (send and receive).
Table 8 summarizes the average measurements. Each measurement is dependent on what the camera sees.
Video traffic will increase and can be reduced based on the moving subject. The audio traffic average should be
added to the total average numbers. Data presentation traffic is variable and dependent on the shared content and
change rate. Table 8 includes examples of the video bandwidth measured during the test, with faster-moving
versus slow-moving or static subjects used in the test file. Note the minimal differences between the TCP and User
Datagram Protocol (UDP) protocols used; however, note the bandwidth usage difference between the static
subject and slow- and faster-moving video subjects.