I have a customer running 8 PCs and 1 server over a 3 GB bonded T1. They are also running 11 VOIP phones.   How munch bandwidth is required to operate office 365? What would be a suitable recommendation for them to upgrade to since they are getting a new phone carrier whi can provide a 10GB connection but they don't want to pay alot if it's overkill.  

Any recommendations? 

Hi,

Please see this discussion and I have copied the part of reply here:

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There are many variables to consider for a user when estimating network traffic. Some of the variables are:

1. The Office 365 service offerings that your organization has subscribed to.
2. The type of task the users client computer is performing (for example, the number of the pages opened).
3. The performance of your Internet browser software (for example, Word Online and Excel Online).
4. Other variables.

Because these variables are unique to each customer environment, as a result, we are not able to provide the accurate official bandwidth requirement for a user. However, we can calculate the average network traffic for each user based on the following assumptions.
a. An average interaction (page load) transfers approximately 100 KB.
b. A typical user generates about 36 interactions (page loads) per hour.
c. About 10 percent of a company's users will be active at the same time.
For detailed steps and the example, please see: BPOS bandwidth / network requirements Company

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Regards,

George Zhao
TechNet Community Support