Figure 1: Creation of a compact dumbbell topology


dosdbell creates a compact dumbell topology using a distribution of hops specified as probability density function (pdf). The parameters of the topology are inputed from a file.


The parameters of the attack tree are specified in the following format. Link bandwidth is specified in Mbps, delays are in ms, and starttime in seconds.

diameter bn_bw bn_delay
TCP_src, link_bw starttime
attackers rate packet_size Master starttime

File Explanation

Line 1: Maximum number of hops, bandwidth(Mbps) and delay(ms) for the bottleneck
Line 2: Background traffic paramaters:
Number of TCP source, link_bw(Mbps) and all TCP sources start by starttime(in sec)
Line 3: Attack traffic parameters:
Number of attackers, attack rate, packet size, presence/Absence of master, and time(in sec) at which the attack starts.
Line 4: Simulation termination time (in sec)
The Master variable is a boolean value to indicate presence/absence (1/0) of a master. If a master is present, then an additional delay component due to the trigger mechanism is added. The model assumes all hops have the same propagation delay(specified as bn_delay). We use TCP Reno (oneway) to model background traffic.

For example: 25 10 20 # Maximum number of hops between two nodes in the original topology is 25,
# bottleneck bandwidth is 10Mbps, propagation delay is 20ms
100 0.1 20 # Hundred TCP sources each send at 100Kbps, all start before 20s
200 0.05 200 0 50 # 200 Attackers, each send at 50Kbps using 200B packets,
no master. The attack starts at 50s
150 # Simulation ends at 150s


Creates a tcl file with the ns topology that can be used directly to run the simulation. The simulation creates a queue trace file,, at the bottle neck link.


dosdbell input_parameters output_tclfile