Bandwidth Considerations for Online Services: Exchange Online, BPOS, etc.
This post will be updated and more flushed out in a few days, but I wanted to share the few bits of information I have gleaned from the Microsoft Assessment and Planning Toolkit for Microsoft Online Services and a few other documents for online services.
First off, when discussing bandwidth considerations for email, know that the bandwidth needed can vary tremendously by worker, scenario, etc. So these are just guidelines and you may have to adjust where needed.
Below is a paste from the proposal document created by the Microsoft Assessment and Planning Toolkit (MAPS). I put in 100 mailboxes to migrate with a total of 150 mailboxes within 3 years. Average mailbox size of 1-2GB. Here is what the proposal document stated:
SNIP\
Guidelines for internet bandwidth utilization for Exchange Online mailboxes are described in the following table:
Table 6. Typical Mailbox User Network Utilization
| Access Method | Average Email User | Heavy Email User |
| Using Outlook Anywhere | 0.215 KB/sec | 0.428 KB/sec |
| Using Outlook Web Access | 0.849 KB/sec | 1.685 KB/sec |
Mailbox migration will require incremental bandwidth calculated by multiplying the number of mailboxes being migrated by the average size of mailboxes in your organization.
Note that users working from home or other locations not on your corporate network will not impact your corporate bandwidth utilization as they are using their own internet connectivity.
Based on the above information, a guideline for the amount of data to be transferred during migration is 200 GB. The following tables provide a guideline for incremental Internet bandwidth requirements based on initial usage and projected usage in 3 years time:
Table 7. Initial Mailbox User Network Utilization
| Access Methods | Average Email User | Heavy Email User |
| Using Outlook Anywhere | 2.15 KB/s | 4.28 KB/s |
| Using Outlook Web Access | 8.49 KB/s | 16.85 KB/s |
Table 8. Initial Mailbox User Network Utilization Guideline
| Access Methods | Average Email User | Heavy Email User |
| Using Outlook Anywhere | 3.225 KB/s | 6.42 KB/s |
| Using Outlook Web Access | 12.735 KB/s | 25.275 KB/s |
Please note that the above calculations are only guidelines as e-mail activity can vary widely by user.
Migration Plan Report
Take these things into account when planning your migration:
Migration Scope
The purpose of this section is to summarize the information you entered in the Migration Planning section of the survey and to provide specific recommendations based on that information.
Table 9. Planned mailbox provisioning
| Mailbox Metric | Value |
| Number of mailboxes initially provisioned: | 100 |
| Number of mailboxes planned to be migrated: | 100 |
| Expected average mailbox size: | 1GB - 2GB |
Planned Migration Time
Microsoft provides the Microsoft Online Mailbox Migration Tool to move data from existing Microsoft Exchange and POP3/IMAP4 mail servers to the Exchange Online environment. The amount of time required to migrate e-mail and other data using this tool depends on three factors:
· How much e-mail is transferred
· How much bandwidth is available via your Internet connection
· How many instances of the Mailbox Migration Tool are run simultaneously
You indicated that your migration will include 100 mailboxes. You also indicated that the current average size of mailboxes in your organization is 250MB - 500MB. Therefore, your total migration size is 50 GB.
The maximum rate of migration per instance of the Mailbox Migration Tool is 2 GB per hour.
You should allocate a minimum of 25 hours for your migration if you plan to use a single instance of the Mailbox Migration tool. The actual time required will be dependent on the amount of Internet bandwidth available from the locations where your Exchange servers are located and by the number of instances of the Microsoft Online Mailbox Migration Tool that are utilized.
For more information about mailbox migration, please refer to the “Migrate to Microsoft Online” whitepaper at http://go.microsoft.com/fwlink/?LinkId=128821.
/END SNIP
I’ll elaborate more later. The first thing that stands out to me is how much more bandwidth OWA requires than Outlook 2007 (anywhere – RDP over HTTPS).
-Woody