[GridSim-users] Problems with communications

[Héctor B. de F. <hec...@di...>]

Hello.
Finally I have adapted GridSim to simulate a multicluster environment, and
implemented some kind of communications between nodes. But, I have a
problems with the behavior of it. The working model is at follows: The
user sends a gridlet to every of the required gridresources (working as an
unique node, meaning that one resource has only one PE), and immediatelly,
the user sends a notification to the nodes, with the order to communicate
with the res of the nodes. Then, every one sends a big packet (20-40 MB)
to the others.
While the nodes are transmitting, they pause the execution of its gridlet,
to simmulate a blocking communication of the nodes.
All seems to work well, until I read the execution time of the gridlets.
If we have for example two clusters, one with a 100mbps channel, and the
other with 100mbps, the gridlets last (for example) 1000 seconds to
finnish. But If I change the channels to (for example, this combination):
100mbps, and 10mbps, the finnish time of the gridlets last the same. This
not changes until I reduce even more the BW of one of the channels, to
100mbps and 1mbps. These ranges of BW have not much sense as, changing to
100mbps and 20mbps has no real impact on it. I revised the event traces,
and all seems correct. Only the finnish time seems to do strange things.

I use RIPRouter, Simplelink, and FIFOScheduler as the network elements.
and the topology is the following: a main router, where the user and the
clusters (with a router for every cluster) are connected to it. The
gridresources are connected to the router of its corresponding cluster.

Anyone has a idea of why the simulation has its strange behavior? Maybe
I'm doing something incorrectly, but in one week revising the code and the
network examples I can't figure which is the problem.

Sorry for a too big message, but I wanted to give as much detail as possible.


Best regards,

Hector.

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Hector Blanco de Frutos

Dept. d'Informàtica i Enginyeria Industrial
Escola Politècnica Superior
Universitat de Lleida
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