How To Fix D-311 - RFC block size outside valid boundaries [2kB - 4MB]

SAP Error Message - Details

• Message type: E = Error

• Message class: D- -

• Message number: 311

• Message text: RFC block size outside valid boundaries [2kB - 4MB]

Self-Explanatory Message

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Smart SAP Assistant

• What is the cause and solution for SAP error message D-311 - RFC block size outside valid boundaries [2kB - 4MB] ?

  The SAP error message D-311, which indicates that the RFC block size is outside valid boundaries (2kB - 4MB), typically arises when there is an issue with the configuration of the Remote Function Call (RFC) settings in your SAP system. This error can occur in various scenarios, such as when trying to establish a connection between SAP systems or when executing remote function calls.
  Cause:
  
  Invalid Block Size Configuration: The block size specified for the RFC connection is either too small (less than 2kB) or too large (greater than 4MB).
  Network Issues: Sometimes, network configurations or limitations can lead to incorrect block size settings being applied.
  SAP Kernel Version: An outdated or incompatible SAP kernel version may not support the specified block size.
  Parameter Settings: Incorrect settings in the SAP profile parameters related to RFC communication.
  
  Solution:
  
  
  Check RFC Configuration:
  
  Go to transaction SM59 (RFC Destinations) and check the settings for the RFC destination that is causing the issue.
  Ensure that the block size is set within the valid range (2kB - 4MB).
  
  
  
  Adjust Profile Parameters:
  
  Check the instance profile parameters related to RFC. The parameters to look for include:
  
  rfc/blocksize
  
  
  You can adjust these parameters using transaction RZ10 (Edit Profile) and then restart the instance for the changes to take effect.
  
  
  
  Update SAP Kernel:
  
  If you are using an outdated version of the SAP kernel, consider upgrading to a more recent version that supports the required block sizes.
  
  
  
  Network Configuration:
  
  Ensure that there are no network devices (like firewalls or routers) that might be limiting the size of the packets being sent over the network.
  
  
  
  Testing:
  
  After making changes, test the RFC connection again to see if the issue is resolved.
  
  
  
  Related Information:
  
  SAP Notes: Check SAP Notes related to RFC issues for any specific patches or updates that may address this error.
  Documentation: Review the SAP documentation for RFC settings and best practices to ensure that your configuration aligns with recommended guidelines.
  Logs: Check the system logs (transaction SM21) and developer traces (transaction ST22) for any additional error messages that may provide more context about the issue.
  
  If the problem persists after trying the above solutions, consider reaching out to SAP support for further assistance.