Applet n. 1.1 | |
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This animation file: gzipped. The script used: bwxd.tcl Parameters for this animation: ns bwxd.tcl 10Mb 4ms 1 0.5 Description:These two hosts are connected by means of a 10Mbit/s, 4ms delay link. Host 0 is using a Stop-and-Wait protocol. The line is very ineficiently used. |
Applet n. 1.2 | |
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This animation file: gzipped. The script used: bwxd.tcl Parameters for this animation: ns bwxd.tcl 10Mb 4ms 10 0.5 Description:The two hosts are connected by means of a 10Mbit/s, 4ms delay link. Host 0 is using a window with capacity for 10 segments of 500bytes. The pipe is not being filled with packets and therefore the link is not being efficiently used. The effective bandwidth is, in this case, approximately (10pkt*500bytes*8)/0.008 = 5Mbit/s, half of the available bandwidth. |
Applet n. 1.3 | |
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This animation file: gzipped. The script used: bwxd.tcl Parameters for this animation: ns bwxd.tcl 10Mb 4ms 20 0.5 Description:Bandwidth x Delay = 40000bits = 10 packets of 500 bytes; we have adjusted the window to 20 packets but the pipe is still not full. Why? In our previous calculus we assumed the first ACK was sent exactly when the reception at n1 of the first packet begins. That is not true; the first ACK is sent when the reception of the first packet finishes and the packet is processed (you may need to slow down a bit the animation to see this fact). |
Applet n. 1.4 | |
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This animation file: gzipped. The script used: bwxd.tcl Parameters for this animation: ns bwxd.tcl 10Mb 4ms 21 0.5 Description:We have added one packet more to the size of the window in the previous example; now we are keeping the pipe full. |