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Configuring virtual Ethernet to support unusual non-TCP applications that do not negotiate MTU

Note:
To avoid impacts to normal applications that negotiate MTU, before performing this procedure you may want to define a separate virtual Ethernet network or separate IP addresses for the application that does not negotiate MTU.
  1. Do one of the following.
    1. If all Windows endpoints will use an iSCSI network having a maximum frame size of 1500 bytes or greater, configure the iSCSI HBA Ethernet frame size at all Windows endpoints to a value as large as possible without exceeding the most constrained iSCSI network's maximum frame size.
    2. If any Windows endpoint will use an iSCSI network having a maximum frame size less than 1500 bytes, configure the virtual Ethernet Maximum frame size at all Windows endpoints to a value is as large as possible without exceeding the most constrained iSCSI network's maximum frame size.
  2. At other endpoints, set the MTU to a value determined by subtracting 116 from the smaller of the Windows iSCSI HBA Ethernet frame size and the virtual Ethernet Maximum frame size. For i5/OS™ endpoints, you can accomplish this by performing the following procedure.
    1. Using iSeries™ Navigator, expand Network—>TCP/IP Configuration—>IPv4—> Interfaces.
    2. Right-click the interface with the IP address and line description name of interest and select Properties.
    3. On the Advanced tab, type the calculated value in the Maximum transmission unit field and click OK to save the change.
    Note:
    If you want to use the command line interface, use CFGTCP and select option 1, Work with TCP/IP interfaces.
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