Simple network bandwidth consumption calculation for Office 365

Microsoft Office 365 combines Microsoft Office desktop suite with cloud-based versions of communication and collaboration services like Microsoft Exchange Online, Microsoft SharePoint Online, Microsoft Office Web Apps, and Microsoft Lync Online. Each of these, online provided, services has its own bandwidth requirements.

When estimating network traffic, there are many variables to consider. Some of these are:

  • The online services that your company has subscribed to
  • The number of client computers that is in use simultaneously
  • The task each client computer is performing
  • The company’s network topology and the capacity of the various pieces of network hardware
  • The number and the capacity of the network connections and network segments associated with each client computer

In this article we are going to provide guidelines for rough (simple) estimation of the network bandwidth, each service is going to consume. Detailed specifications are beyond the scope of this article. For detailed documentation, business requirements, assessment and deployment preparation you can go to OnRamp for Office 365

Microsoft Exchange Online

In this section we are going to estimate the network bandwidth that your company would need to access Microsoft Exchange Online. To do this, we are going to use a very useful tool called Exchange Client Network Bandwidth Calculator and you can find it here. This tool can help you to reduce the risks involved in Exchange Server network bandwidth planning and is suitable for Exchange Online as well as Exchange On Premises.

If you are already running Exchange Server On Premises you can use PowerShell or tools like Exchange Server Profile analyzer, in order to determine mailbox size, average message size, messages sent and received per mailbox per day etc.

In this calculation we have used User Profile data as suggested by the Exchange Client Network Bandwidth Calculator. The following table lists the message usage for light, medium, heavy, and very heavy e-mail users

Activity Light Medium Heavy Very Heavy
Messages sent per day 5 10 20 30
Messages received per day 20 40 80 120
Average message size 50 KB 50 KB 50 KB 50 KB
Average Mailbox Size 2 GB 2 GB 2 GB 2 GB

The network traffic that is generated by each type of user in each e-mail client, is on the following table. All values are in kilobytes (KB) per day per user.

E-Mail Client Light Medium Heavy Very Heavy
Outlook 2010 (OA-Cached),Receive 2435 KB 3701 KB 6233 KB 9437 KB
Outlook 2010 (OA-Cached),Send 319 KB 638 KB 1277 KB 1915 KB
OWA 2010,Receive 1835 KB 3635 KB 7229 KB 10823 KB
OWA 2010,Send 561 KB 1122 KB 2244 KB 3365 KB
Outlook 2011 (EWS),Receive 3317 KB 5276 KB 9194 KB 14097 KB
Outlook 2011 (EWS),Send 1061 KB 2122 KB 4243 KB 6365 KB

To apply this information to your company, consider the following examples. Each example assumes that the users are in the same time zone and that they perform most of their work during the same eight hours of the day.

  • Example 1, 50 Heavy Outlook 2011 users: In order to calculate the network bandwidth consumption in bytes per second, we must use the following formula
    Received bytes/sec = (50 heavy users × (9,194 KB/user ÷ day)) ÷ (8 hr/day × 3600 sec/hr) = 15.96 KB/sec
    Sent bytes/sec = (50 heavy users × (4,243 KB/user ÷ day)) ÷ (8 hr/day × 3600 sec/hr) = 7.36 KB/sec
    These are average rates, if we assume a daily peak of twice the average usage, the network connection would need to support approximately 32 KB/sec of Download Speed and 16 KB/sec of Upload speed.
  • Example 2, 30 Medium OWA users: In order to calculate the network bandwidth consumption in bytes per second, we must use the following formula
    Received bytes/sec = (30 heavy users × (7,229 KB/user ÷ day)) ÷ (8 hr/day × 3600 sec/hr) = 7.53 KB/sec
    Sent bytes/sec = (50 heavy users × (2,244 KB/user ÷ day)) ÷ (8 hr/day × 3600 sec/hr) = 2.33 KB/sec
    These are average rates, if we assume a daily peak of twice the average usage, the network connection would need to support approximately 16 KB/sec of Download Speed and 6 KB/sec of Upload speed.

You can use the Exchange Client Network Bandwidth Calculator spreadsheet and choose your users profiles mixing.

Microsoft SharePoint Online

In this section we are going to estimate the network bandwidth that your company would need to access Microsoft SharePoint Online. This estimation is based to the following assumptions:

  • An average page load (interaction) transfers approximately 100 KB.
  • A typical user generates about 40 interactions per hour.
  • About 20 percent of a company’s users will be active at the same time.

With that been said, consider the following example, having in mind that this example assumes that all of the users are in the same time zone and that they perform most of their work during the same eight hours of the day.

In this example a company has 100 SharePoint Online Users and we calculate the average network traffic for each user using this formula: bits per second = (102,400 bytes/load × 8 bits/byte × 40 loads/hr) ÷ 3600 seconds/hr = 9102 bits per second

With the assumption that only 20% of company’s users will be active at the same time, those 20 users would require 20 × 9102 bits per second = 177,77 Kilobits per second.

if we assume a daily peak twice the average usage, the network connection would need to support approximately 360 Kb/sec.

In addition to the bandwidth requirement, SharePoint Online requires a network latency of no greater than 250 milliseconds.

For more detailed information about capacity planning for SharePoint Online, see Plan for bandwidth requirements.

Microsoft Lync Online

The estimation of bandwidth requirements for Microsoft Lync Online can be challenging as it depends on many parameters.

Generally, the network bandwidth usage is based on each user. The starting point for understanding the network bandwidth requirements for Lync Online is documented in the article, Network Bandwidth Requirements for Media Traffic, published in Microsoft Technet

There is also a bandwidth calculator available for download.

In planning phase you can use the Transport Reliability IP Probe (TRIPP) tool using the following URLs according to your physical location:

This tool can help you determine connectivity or bandwidth problems

The bandwidth usage is determined by a number of factors, the Codec used (along with overhead), the Stream activity level and for video, the resolution/quality and frame rate.

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