E-mail synchronization appears slow when multiple "Migration Agent for Exchange" (MAGE) agents are installed on a single agent host server.
Microsoft confirmed that the slowness may be caused by the ‘TCP Auto-Tuning’ feature built into Windows 7/2008/R2.
TCP Auto-Tuning feature is enabled by default. The TCP receive window size is automatically tuned for each individual connection based on the bandwidth delay product (BDP) and the rate at which the application reads data from the connection.
Perform the following steps to verify TCP Auto-Tuning state and disable it:
1. Open elevated command prompt with administrator’s privileges.
2. Type the following command and press Enter:
netsh interface tcp show global
The system will display the following text on screen, where you can check on the Auto-Tuning setting:
Querying active state…
TCP Global Parameters
———————————————-
Receive-Side Scaling State : enabled
Chimney Offload State : enabled
Receive Window Auto-Tuning Level : normal
Add-On Congestion Control Provider : none
ECN Capability : disabled
RFC 1323 Timestamps : disabled
To disable TCP Auto-Tuning type the following command and press Enter:
netsh interface tcp set global autotuning=disabled
