Fat tree

[pledesma3]

Hello, I implemented a fat tree topology. However, whenever I try to have 2 specific virtual machines communicate with each other, it says it cannot find the path from the source virtual machine to the destination. Any help would be appreciated. Thank you.

[AhmedFaeq1]

I don't know how to help because I'm still new to cloudsim.
Anyhow I'm trying to do the same but BRITE generator is required to build the network topology.
Could you please tell me how did u make it?
If you have the BRITE tool please send me.
Thanks a lot

[jayjmin]

Hi pledesma3,
Please check your json files - for both physical and virtual topology. In physical topology json file, "links" object should list all the links between physical switches and hosts. Also, in virtual topology json file, the virtual private network topology between VMs should be provided in "links" object. Please check your both json files, and make sure there are available links between physical hosts, as well as VMs.

[pledesma3]

@Fogony Thank you I was able to fix it. Is it possible to place moultiple VM's in a host? Because that is the next thing I am trying to do, and it doesn't seem to work. Thank you

[jayjmin]

Multiple VMs can be placed in a host, but you have to make sure the capacity of a host is enough to hold multiple VMs. Check the MIPS, RAM, storage size of a host and a VM, e.g. a host with 2000 mips can accept 2 VMs with 1000 mips. This decision is made at VM allocation policy, so check out your VM allocation policy if it's not working.

[pledesma3]

@jayjmin Thank you for the help. I am trying to show that the fat tree topology is more energy efficient than the regular tree topology. How can I create congestion on a tree topology with the workload file, and use that same workload file on a fat tree topology to show that a tree topology has only 1 route between 2 VM's, and a fat tree has multiple routes. Because I keep trying this, and the fat tree uses more energy, it doesn't seem to find more than one route

[jayjmin]

@pledesma3 , Fat-Tree is not necessarily more energy efficient than canonical tree topology. Fat-tree is beneficial to provide more bandwidth for hosts, but it usually consumes more energy. Basically Fat-Tree has more number of switches, with multi-pathing, which will turn on more switches for the same amount of network traffic. It's good for load-balancing, but not really beneficial for energy efficiency.