Two flows with different cycle merge into the same link

[mopean]

Hi,
Thanks for your code. I am running an example on the project.
My example has two flows as follows:

Flow flow0 = new Flow(Flow.UNICAST);
flow0.setStartDevice(dev4);
flow0.addToPath(switch0);
flow0.addToPath(switch2);
flow0.setEndDevice(dev10);
flow0.setFlowSendingPeriodicity(2000);


Flow flow1 = new Flow(Flow.UNICAST);
flow1.setStartDevice(dev5);
flow1.addToPath(switch1);
flow1.addToPath(switch2);
flow1.setEndDevice(dev10);
flow1.setFlowSendingPeriodicity(3000);

The topology is:

Dev4 -> SW0 -> SW2 -> Dev10
                ^
                |
Dev5 -> Sw1 -> 

And the result is:

>>>> INFORMATION OF SWITCH: switch0 <<<<
    Port list - 
        => Port name:       switch0Port1
        Connects to:     switch2
        Cycle start:    0.0
        Cycle duration: 2000.0
        Fragments:       flow1Fragment1, 
        Priority number: 7
          Index 0 Slot start:      1949.088
          Index 0 Slot duration:   8.004
        ------------------------


>>>> INFORMATION OF SWITCH: switch1 <<<<
    Port list - 
        => Port name:       switch1Port1
        Connects to:     switch2
        Cycle start:    0.0
        Cycle duration: 3000.0
        Fragments:       flow2Fragment1, 
        Priority number: 7
          Index 0 Slot start:      2940.996
          Index 0 Slot duration:   8.0
        ------------------------


>>>> INFORMATION OF SWITCH: switch2 <<<<
    Port list - 
        => Port name:       switch2Port9
        Connects to:     dev10
        Cycle start:    0.0
        Cycle duration: 1000.0
        Fragments:       flow1Fragment2, flow2Fragment2, 
        Priority number: 7
          Index 0 Slot start:      949.992
          Index 0 Slot duration:   50.0
        ------------------------

I notice that Cycle duration of Switch2 is 1ms. It means that there is a slot in 1ms. But cycle of flow0 is 2ms, and cycle of flow1 is 3ms. There will has two slot without packets within every 6ms.

I think it is better that the Cycle duration of Switch2 shall be 6ms (i.e. Least Common Multiple of two flow). In each cycle, there are four time slots .

Which part of the code do I need to modify？
Thanks

[ACassimiro]

Hello. The default strategy for schedule generation uses a strategy that we call "microcyles" which, as you pointed out, generates a cycle of size equals to the greatest common divisor of all flow periods. To use the least common multiple instead, a scheduling strategy that we refer to "hypercycle", after declaring a port of a switch, use the method setUseHyperCycle(true) on that port to enable the hypercycle strategy on its cycle.

[mopean]

hi，Thank you for your response. I have set the port of switch2 to hypercycle which is connected to dev10 in my example.

Dev4 -> SW0 -> SW2 -> Dev10
                ^
                |
Dev5 -> Sw1 -> 

Code:

		Port switch2Port=switch2.createPort(dev10, cycle100);
		switch2Port.setUseHyperCycle(true);

But it doesn't seem to work，the Cycle duration of Switch2 is still 1ms.