Ingeniero

Este es el programa original del libro “Introducción to Network Simulator NS2”

Program 1.3 Simulation skeleton of a single-channel queuing system.

1 % Initialize system states
2channel_free = true; %Channel is idle
3 num_queue = 0; %Number of packets in queue
4 num_system = 0; %Number of packets in system
5 SimClock = 0; %Current time of simulation

6%Generate packets and schedule their arrivals
7 event_list = create_list();

8 % Main loop
9 while {event_list != empty} & {SimClock < stopTime}
10 expunge the previous eventfrom event list;
11 set SimClock := time of current event;
12 call current event;
13 end while

14 %Define events
15 pkt_arrival(){
16 if(channel_free)
17 channel_free =false;
18 num_system = num_system + 1;
19 % Update "event_list": Put "successful packet tx event"
20 % into "event_list," T is random service time.
21 schedule event "pkt_complete" atSimClock + T;
22 else
23 num_queue = num_queue + 1; %Place packet in queue
24 num_system = num_queue + 1;
25 }

26 pkt_complete(){
27 num_system = num_system - 1;
28num_queue = num_queue - 1;
29 if(num_queue > 0)
30 schedule event "pkt_complete" at SimClock + T;
31 else
32 channel_free = true;
33 num_system = 0;
34 num_queue = 0;
35 }Sin embargo hay que hacer algunas correcciones, por tanto se propone el siguiente cambio:

1 % Initialize system states
2 channel_free = true; %Channel is idle
3 num_queue = 0;%Number of packets in queue
4 num_system = 0; %Number of packets in system
5 SimClock = 0; %Current time of simulation

6 %Generate packets and schedule their arrivals
7event_list = create_list();

8 % Main loop
9 while {event_list != empty} & {SimClock < stopTime}
10 expunge the previous event from event list; % aunque se podría quedar para log...