IJ12817: SEA PLSO_BRIDGE=YES LARGE_RECEIVE PACKET CORRUPTION APPLIES TO AIX 7100-05

APAR status

• Closed as program error.

Error description

• On Power8/9 vios 2.2.6.3x introduced SEA plso_bridge=yes
  mode that sends aggregated large_receive packets as
  "platform largesend" packet to client VEAs.
  If the receiving client VEA is not PLSO enabled the power
  hypervisor will segment the large_receive packet.
  Due to a problem with segmenting padded TCP frames this
  will sometimes result in modified data packets.
  Encrypted TCP sessions will experience
  hang/timeout/abbort
  situations.
  

Local fix

• disable "plso_bridge" on all SEA devices:
  (use the right SEA adapter number instead of "X")
  $ chdev -dev entX -attr plso_bridge=no
  The change is dynamic and doesn't require a reboot.
  

Problem summary

• *
    * USERS AFFECTED:
    * Systems running the AIX 7200-03 Technology Level
    * or VIOS 3.1.0.x
    * with devices.common.IBM.ethernet.rte at
    * the 7.2.3.15 level.
  *
    * PROBLEM DESCRIPTION:
    * TCP sessions through VIOS SEA can slow, hang, timeout, or
    * cause extra zeroes to be added to the tcp payload data.
    *
    * This can happen if the SEA on the VIOS is configured with:
    * - large_receive=yes (non-default setting)
    * AND
    * - plso_bridge=yes (default setting on affected VIOS levels)
    *
    * This includes data transferred between VIOSes during LPM.
    *
  * The APAR/iFix should be applied to the VIOS to prevent these
    * issues.
    * As a workaround, the SEA attributes can be modified:
    * For SEAs bridging traffic to AIX LPARs only, set
    * plso_bridge=no
    * For SEAs bridging traffic to any Linux LPARs, set
    * large_receive=no
  *
    * RECOMMENDATION:
    * Install APAR IJ12809.
    * Prior to fix availability, an interim fix is available from
    * either
    * ftp://aix.software.ibm.com/aix/ifixes/ij12809/
    * https://aix.software.ibm.com/aix/ifixes/ij12809/
    * Installation of the ifix requires a reboot.
  *
  

Problem conclusion

• Code fixed to avoid the corruption.
  

Temporary fix

Comments

• 6100-09 - use AIX APAR IJ12143
  7100-04 - use AIX APAR IJ12816
  7100-05 - use AIX APAR IJ12817
  7200-01 - use AIX APAR IJ12818
  7200-02 - use AIX APAR IJ12819
  7200-03 - use AIX APAR IJ12809
  

APAR Information

• APAR is sysrouted FROM one or more of the following:

  IJ12143

• APAR is sysrouted TO one or more of the following:

Fix information

• Fixed component name

  AIX V7.1

• Fixed component ID

  5765H4000

Applicable component levels

• R710 PSY U883404

     UP19/05/01 I 1000