Further to this blog... http://blogs.vmware.com/vsphere/2011/10/vsphere-replication-bandwidth-1.html and this: http://blogs.vmware.com/vsphere/2011/10/vsphere-replication-bandwidth.html In theory, 100mbps LL can transmit ~ 45GB per hour, that's around 1TB per day (24 hours). With 70% utilization, we are looking around 700GB of data can be transmitted in 24 days. Block level changes is not equal to changes between two interval. A single file can be changed 100 times in 1 hour, but there will be only one block level change if RPO is 1 hour. The file can be 1mb change every time, with 100 times, we probably are expecting 100mb data changes. However, with RPO 1 hour, we are looking the differences compare with the last snapshot capture. This could be only 1mb or less than 1mb changes. It is not easy or rather no simple calculation can be used to calculate the bandwidth requirement. It is always recommended that we will monitor the bandwidth utilization when vSR is enab