Changes between Version 21 and Version 22 of Internal/RunningDemos

Timestamp:

Dec 23, 2005, 6:34:04 PM (20 years ago)

Author:

kishore

Comment:

—

Internal/RunningDemos

@@ -16 +16 @@
 The objective of this demo is to show the failure of current implementations of IEEE 802.11 infrastructure networks in supporting a large number (O(10)) of clients. The cumulative throughput at the access point (AP) is the measured and it is shown that beyond a certain number of clients, there is a sharp drop rather than graceful degradation. It is hypothesized that the 802.11 bit-rate adaptation algorithm is the primary culprit for this behavior - the algorithm does not differentiate between collision-based packet loss and packet loss due to poor channel conditions. It incorrectly infers collision-based loss as an indication to drop the bit-rate, resulting in the sharp drop in cumulative throughput.
 
-The demo itself consists of one receiver and 25 senders -- the start times of the senders are staggered (3-4 senders join the experiment in 10 second intervals). Traffic generated is UDP-CBR (constant bit-rate) at 1.5Mbps emulating high-quality video streaming from the clients to the AP. All the clients and the AP use 802.11a (channel 36 (5.18Ghz)) with negligible interference from other sources.
+The demo itself consists of one receiver and 25 senders -- the start times of the senders are staggered (3-4 senders join the experiment in 10 second intervals). Traffic generated is UDP-CBR (constant bit-rate) at 1.5Mbps emulating high-quality video streaming from the clients to the AP. All the clients and the AP use 802.11a (channel 36 (5.18Ghz)) with negligible interference from other sources. The figure below provides a graphical representation.
+
+{{{
+Timeline     SOURCES                                                  DESTINATION
+                                         1.5Mbps UDP CBR on Wireless
+Time 0       Group 1: [1,2],[1,4],[1,8] -------------------------------> [5,4]   
+Time 10      Group 2: [2,1],[2,3],[2,5] -------------------------------> [5,4]
+...
+
+Time 60      Group 7: [8,1],[8,5],[8,7] -------------------------------> [5,4]
+
+Time 110     Stop Group 1 senders.
+Time 115     Stop Group 2 senders.
+...
+Time 140     Stop Group 7 senders.
+}}}
 
 === Steps to Execute Demo ===