VM66426: NETWORK PACKET MARKED INCORRECTLY AS TX ERROR

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• When using IBM Communication Server for Linux with a VSwitch,
  packets may be dropped and incorrectly marked as TX Error.
  
  The interface being used is a SNA LLC2 port on IBM Communication
  server. The problem occurs when the guest interface is
  configured an Access port on a VLAN AWARE ETHERNET (layer 2)
  VSwitch.
  
  In this scenario, CP needs to insert the VLAN tag into the
  Ethernet frame before sending it through the Virtual Switch.
  The packet length is adjusted to account for the VLAN tag.
  In the case of very small LLC packets, a logic error turns
  it into a malformed packet that is dropped as an Error
  instead of being delivered to the destination (or transmitted
  via the uplink port).
  

Local fix

• Apply PTF
  

Problem summary

• ****************************************************************
  * USERS AFFECTED: All VSwitch users configured with Access     *
  *                 ports using non-IP protocols.                *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  ****************************************************************
  * RECOMMENDATION: APPLY PTF                                    *
  ****************************************************************
  When very short packets are transmitted by an access port on a
  VLAN AWARE VSwitch, network packets may be incorrectly marked as
  TX error.
  

Problem conclusion

• A logic error incorrectly incremented a pointer to the wrong
  value when inserting the VLAN tag for a network packet
  being transmitted from an Access port.  This error only
  caused an issue with a short network packet, such as one
  used in the SNA LLC2 protocol.
  The setting of this pointer has been corrected.
  

Temporary fix

Comments

APAR Information

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

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

  UM35721 UM35722

Modules/Macros

• HCPVQA
  

Fix information

• Fixed component name

  VM CP

• Fixed component ID

  568411202

Applicable component levels

• R710 PSY UM35721

     UP21/06/29 P 2101

• R720 PSY UM35808

     UP21/01/12 P 2101

Fix is available

• Select the PTF appropriate for your component level. You will be required to sign in. Distribution on physical media is not available in all countries.