Re: [GridSim-users] some questions

[Anthony S. <an...@cs...>]

Questions:
>1. Is the any algorithm in GridSim to chose the "best" network way? 
>because in my case simulator use only direct link
>Router1-Router2 (100Mb/s) and not Router1-Router3-Router2 (1.2Gb/s).

In FloodingRouter.java and RIPRouter.java description:
"In case there are more than two routes to a destination, the route with 
the lower hopcount is used."
You can add a new router that finds the biggest pipe instead.

>2. Is the any relations between resources characteristic and file
>transfer time? Or file transfer time just depend on
>size of file and bandwidth?

file transfer time just depend on size of file and bandwidth.

>3.  When I've tried to send 100Mb files through network with a different 
>bandwidth (10Mb/s, 100Mb/s, 1000Mb/s) I always
>received the same time - something about 669. Why it is?

I don't know. Perhaps the router finds the shortest route
which may have the bottleneck/small pipe.


>But when  I've tried to use the same bandwidth (100Mb/s) for different 
>files (10Mb, 100Mb, 1000Mb),
>i received the next time: 69.8; 669.8; 6669.8. And for transfer one file 
>1000Mb I have to wait half an hour, it's to
>long can it be faster?!

the half an hour simulation time is due to overheads of creating
many Java objects for network packets, scheduling them,
and synchronization of threads.
This time refers to simulation/experiment runtime.
It has nothing to do with GridSim.clock().

A large object is partitioned into packets
according to MTU. Hence, num packets = object size / MTU.
In GridSim, we set Link#DEFAULT_MTU = 1500.

That's why for datagrid, my colleague, James, has come up with
the flow network simulation that aims to make the simulation
runs faster.

I have integrated his work to the main trunk.
It is available on
http://gridsim.svn.sourceforge.net/viewvc/gridsim/trunk/

You can help us with testing this functionality.
It is not yet ready for release.


anthony


> I have some questions about GridSim.
>
> I've tried to make some test about files transfer  in GridSim. I've created 
> two resources, 3 routers between (one direct link and one link through third 
> router ), and one user on one of resource. Files were on one resource. User 
> try to replicate files from Res_1 to res_2.
> Config:
>
> 3
> Router1
> Router2
> Router3
> Router1 Router2 0.10 10.0 1500
> Router1 Router3 1.2 10.0 1500
> Router2 Router3 1.2 10.0 1500
>
> Res1 25000 0.1 Router1 regionalRC1 File_name_0 File_name_1 File_name_2 
> File_name_3 File_name_4 File_name_5 File_name_6 File_name_7 File_name_8 
> File_name_9 Res2 20000 0.1 Router2 regionalRC1
>
> user__Res1 Router1 regionalRC1 
> regionalRC1 0.10 Router1
>
>
>
> Questions:
> 1. Is the any algorithm in GridSim to chose the "best" network way? because 
> in my case simulator use only direct link Router1-Router2 (100Mb/s) and not 
> Router1-Router3-Router2 (1.2Gb/s).
> 2. Is the any relations between resources characteristic and file transfer 
> time? Or file transfer time just depend on size of file and bandwidth?
> 3.  When I've tried to send 100Mb files through network with a different 
> bandwidth (10Mb/s, 100Mb/s, 1000Mb/s) I always received the same time - 
> something about 669. Why it is?
> But when  I've tried to use the same bandwidth (100Mb/s) for different files 
> (10Mb, 100Mb, 1000Mb),
> i received the next time: 69.8; 669.8; 6669.8. And for transfer one file 
> 1000Mb I have to wait half an hour, it's to long can it be faster?!
> As you said we couldn't have any correlation of this simulation time with the 
> real, for example, we've got 6669.8 and it does not mean that real file would 
> be transfered in 10 minutes. But what this time mean? just that something 
> happened in this time?
>
>
> Thanks in advance,  I hope you have time to answering me
>
> Best regards, Andrey
>