Bandwidth planning for Exchange Online migrations may seem boring, but it’s essential for a successful move to Office 365.
A badly planned move to Office 365 can cripple an organization if the bandwidth requirements aren’t investigated before migrating. Although services such as Exchange Online aren’t bandwidth heavy in daily use, services such as Lync can be, depending on workloads.Bandwidth planning for Exchange Online migrations can be a dry subject, but it’s essential for a successful move. It isn’t as simple as plugging the values into the Microsoft calculators. Admins need to use values and other data to understand where the weak points are and remediate.
It’s important to look at end users across the organization and perform calculations using Microsoft tools to understand the impact of these Exchange Online requirements. Admins can then use the results to understand if they’ll need to make upgrades. We’ll focus on how to perform this planning and understand the ongoing requirements for using Office 365.
Before we begin, it’s essential to understand how clients access Office 365. Typically, an Outlook client will connect from its local site directly to the Internet, or, if it’s on a wide area network (WAN), at the closest site with Internet breakout. The client will perform a DNS lookup to obtain the nearest Office 365 point of presence and connect over HTTPS to the service. This typically provides reasonably low latency when accessing the service.
During a migration, it’s typical to switch on features such as Cached Mode and upgrade clients in advance. The Offline Cache stays intact after a hybrid migration, so this removes the need for every client to re-download the mailbox en masse.