Dell ThinOS 2402 and 2405 Administrator’s Guide

Maximum Transmission Unit (MTU) discovery in Enlightened Data Transport (EDT)

From ThinOS 2311 and Citrix Workspace App package 23.9.0.24.4, Maximum Transmission Unit (MTU) discovery in Enlightened Data Transport (EDT) is supported.

• MTU increases the reliability and compatibility of the EDT protocol and provides an improved user experience.
• MTU Discovery enables EDT to automatically determine the Maximum Transmission Unit (MTU) when establishing a session.
• This prevents EDT packet fragmentation that might result in performance degradation or failure to establish a session.
• System requirements:
  • Citrix Virtual Delivery Agent (VDA) 2003 and later
  • Citrix Workspace app package version 23.9.0.24.4 and later
  • Session reliability enabled
• MTU Discovery is enabled by default. To disable EDT MTU Discovery, configure the following registry values and restart the VDA:
  • Key: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Terminal Server\Wds\icawd
  • Value name: MtuDiscovery
  • Value type: DWORD
  • Value data: 0

    This setting is machine-wide and affects all sessions connecting from a supported client.

• To configure Maximum Segment Size (MSS) when using EDT on networks with nonstandard MTU, do the following:
  1. You can set the EDT MTU Discovery Registry key value below to disabled (value 0) and restart the VDA.
     • Key: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Terminal Server\Wds\icawd
     • Value name: MtuDiscovery
     • Value type: DWORD
     • Value data: 0
       NOTE:If the value is 1, then MTU discovery is enabled. If the value is 0, MTU discovery is disabled.
  2. You can also configure the MTU or MSS rates manually by doing the following:
     1. On Admin Policy Tool or Wyse Management Suite policy settings, go to Advanced > VDI Configuration Editor > Citrix Configuration Editor.
     2. In Citrix INI Settings, click Add Row.
     3. From the File drop-down list, select All_Regions.ini.
     4. From the Operation drop-down list, select Add or Update.
     5. In the Section field, enter Network\UDT.
     6. In the Key field, enter edtMSS.
     7. In the Value field, enter a value, such as 1480. The MTU value must be determined for each network independently and is not a one-size-fits-all solution.
     8. Sign out or restart the device for the settings to take effect.
        NOTE:By design, Citrix Workspace App does not support disable EDT MTU Discovery from the client side. You can enable or disable EDT MTU Discovery on VDA.