PK08183: ADD OPTION TCP_NODELAY TO SOCKET OPTIONS FOR INCREASE NETWORK TRAFFIC THROUGHPUT.

APAR status

• Closed as program error.

Error description

• This apar results from Marketing requirement MR052705392 which
  suggest that IMS Connect use the TCP-NODELAY Socket Option
  setting on the USS SETSOCKOPT interface calls to increase the
  TCP/IP host network traffic throughput. TCP_NODELAY causes TCPIP
  to bypass the logic that uses the 'NAGEL ALGORITHM' eliminating
  a .2 second delay before sending subsequent partially filled
  packets to the end user.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All IMS Connect 9.1 Users                    *
  ****************************************************************
  * PROBLEM DESCRIPTION: Introduction of NODELAY protocol        *
  *                      option in HWSCFGxx                      *
  ****************************************************************
  * RECOMMENDATION: INSTALL CORRECTIVE SERVICE FOR APAR/PTF      *
  ****************************************************************
  This apar introduces a new parameter NODELAY=(Y|N) in
  HWSCFGxx (IMS connect configuration file) for the TCPIP
  configuration statement. This parameter drives the activation
  of TCP_NODELAY protocol option.
  

Problem conclusion

• AIDS: RIDS/UTIL RIDS/DBS DBS/UTIL
    DEP: NONE
    GEN:
  
  *** END IMS KEYWORDS ***
  A new parameter NODELAY=(Y|N) in HWSCFGxx (IMS connect
  configuration file) has been introduced for the TCPIP
  configuration statement.
  This parameter drives the activation of the TCP_NODELAY
  protocol option at IPPROTO_TCP level.
  TCP_NODELAY option specified as Y will disable the Nagle
  buffering algorithm and force a socket to send the data
  in its buffer.
  ---------
  The folloing manual has been changed:
  SC18726002
  -
  THE FOLLOWING TEXT DESCRIBES THE DOC CHANGE:
  IMS Connect Configuration Statement Parameters
  ....
  NODELAY=
  Specifies whether TCP/IP protocol option TCP_NODELAY is to
  be used.
  Set NODELAY to yes or no as follows:
  Y for yes
  N for no (this is the default)
  
  When NODELAY=Y is specified, IMS CONNECT will set TCP_NODELAY
  option at IPPROTO_TCP level for all USS API interface calls,
  thus disabling the Nagle algorithm.
  Using the NODELAY option can enhance IMS Connect performance
  and increase the throughput because it forces a socket to
  send the data in its buffer without having to wait for an ACK
  from the client's TCP/IP.
  This parm plays a role only when sending packets.
  NOTE: THIS OPTION CAN BE ALSO VERY INEFFICIENT FOR 2
  REASONS:
  - CAN CAUSE THE NETWORK TRAFFIC TO INCREASE, WITH SMALLER
    THAN NEEDED PACKET USING BANDWIDTH.
  - ADD THE OVERHEAD OF HAVING A 40 BYTES HEADER EVEN FOR
    1 BYTE PACKET SEND
  

Temporary fix

• *********
  * HIPER *
  *********
  

Comments

APAR Information

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

  PK06448

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

  UK16751

Modules/Macros

• HWSHCDB  HWSHSCT  HWSSDOTD HWSXCFG0
  

Fix information

• Fixed component name

  IMS V9

• Fixed component ID

  5655J3800

Applicable component levels

• R900 PSY UK16751

     UP06/08/04 P F608 Ž