What is the link between the Walrus Controller and the Storage Controller ?

When a user want to upload its save on the Eucalyptus, what happened ?
First the backup applications point in the front-end, CCL (tranks to S3 API) , next the CCL relay to the Walrus ? Next Walrus will scan the good bucket storage to know where the save will be. Then it transfer the data to the Cluster Controller (CC) where the load balancing is installed (do you know an application of load balancing free to eucalyptus ? i know Scalr but it need to pay ..) then the data will be send to the good Node Controller to the good Space Disk ... ??

It's hard to know the relation between each components of Eucalyptus platform.

Need your help, thanks.

Best regard,
Nicolas.