Application and Desktop Application and Desktop Sharing Sharing Omer Boyaci, Henning Schulzrinne, Department of Computer Science, Columbia University 1 2 3 4 Participant Participant Host pplication specific Efficient Participants need application Application has to be modified eneric Inefficient (sometimes) Participants don't need application All applications are supported •Sharing an application with multiple users •There is only one copy of the application •Participants do not need application itself •Briefly, participants •receive screen updates •send keyboard and mouse events Related Work UltraVN C MAST Multicast Application Sharing Tool Kernel space U serspace X 320,340 Y 100,200 X 320,340 Y 100,200 X 320,340 Y 100,200 M irrorDriver 2 X 300,500 Y 200,600 ServerM ain Thread Window coordinates •Participants may have different bandwid •Some participants may join lately. •The effects of packet losses •Reliable multicasting (NACK) •Some regions require different encoding Region> 40,000px ? YES New Region ? NO Use Detected Format YES -1,0,1 coordinates PNG Size Time Stamp counter Region record Create a record & Start Checking Detected ? Continue Checking NO YES PNG/JPG Detection Algorithm What is Application Sharing? Challenges Windows Server Architecture Application Sharing Models Multimedia Support The effect of Packet Loss Retransmissions NACK mechanism for lost packets NACK suppression for multicasting Minimizing the loss effect Small PNG images Around 1500 bytes Several scan lines

Application and Desktop Sharing

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Application and Desktop Sharing. Omer Boyaci, Henning Schulzrinne, Department of Computer Science, Columbia University. What is Application Sharing?. Application Sharing Models. 4. 1. Application specific + Efficient - Participants need application - Application has to be modified - PowerPoint PPT Presentation

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Application and Desktop SharingApplication and Desktop SharingOmer Boyaci, Henning Schulzrinne, Department of Computer Science, Columbia University

Participant ParticipantHost

Application specific+ Efficient- Participants need application- Application has to be modifiedGeneric- Inefficient (sometimes)+ Participants don't need application+ All applications are supported

•Sharing an application with multiple users•There is only one copy of the application•Participants do not need application itself•Briefly, participants

•receive screen updates•send keyboard and mouse events

Related Work

UltraVNC

MASTMulticast ApplicationSharing ToolX 320,340

Y 100,200Kernel space

User space X 320,340Y 100,200

X 320,340Y 100,200

Mirror Driver

2X 300,500Y 200,600

Server Main Thread

Window coordinates

•Participants may have different bandwidths•Some participants may join lately.•The effects of packet losses•Reliable multicasting (NACK)•Some regions require different encoding

Region>40,000px

YES

New Region

Use DetectedFormat

YES

-1,0,1

coordinates

PNG Size

Time Stamp

counter

Region recordCreate a record&

Start Checking