Correlating the data trace and packet trace with the SOCKAPI trace

The SOCKAPI option only records the first 96 bytes of data. To see all the data that was sent or received, you must also activate the data trace or packet trace. The data trace can be correlated easily with the SOCKAPI trace option because both traces are recording data between the application and the TCP/IP stack. The traces can be merged with the IPCS MERGE subcommand. The data trace header contains fields that allow the full data to be correlated.

Figure 1 shows the data trace record corresponding to the READ Exit SOCKAPI trace entry in Figure 2. The server issues READ and waits for a message. The data trace record shows the entire 120 bytes of data because the FULL option was used when starting the data trace. In the READ Exit record, only the first 96 bytes of data are shown.

The records in the two traces can be correlated by the following:

Time: The data trace time must be prior to the READ Exit record time. The data trace time is 20:08:09.181239. The READ Exit record time is 20:08:09.181354.
Jobname: The job name is EZASOKAS in both records.
ASID: The ASID is the server's 0024 (hexadecimal) in both records.
TCB: The TCB is 006E6A68 in both records.
Data length: In the data trace, the length is 78 hexadecimal, which is 120 decimal. The SOCKAPI trace record shows that the return code is 120 (decimal) bytes.
Port: The source port number in the data trace record (11007 decimal) matches the local port number in the SOCKAPI trace record. The destination and remote ports also match (1040 decimal).
IP Address: The IP addresses are handled in the same way as the port numbers. In this example, both the client and server were on the same TCP/IP stack, so the IP addresses are the same.

Figure 1. Data trace record.

 MVS026    DATA      00000003  20:08:09.181239  Data Trace                      
                                                                                
 JOBNAME =    EZASOKAS          FROM  FULL                                      
  TOD CLOCK = XB395B2C2  40035C03                                               
  PKT 2           LOST RECORDS = 0      HDR SEQUENCE NUM = 1                    
 SOURCE IP ADDR = 9.67.113.58      DEST IP ADDR = 9.67.113.58                   
 SOURCE PORT = 11007  DEST PORT = 1040   ASID = X0024  TCB = X006E6A68          
  DATA LENGTH = X0078                                                           
0000 E38889A2 4089A240 8140A2A3 99899587 *This is a string|....@..@.@......*    
0010 40A689A3 88408696 99A3A840 83888199 * with forty char|@....@.....@....*    
0020 8183A385 99A24B40 E38889A2 4089A240 *acters. This is |......K@....@..@*    
0030 8140A2A3 99899587 40A689A3 88408696 *a string with fo|.@......@....@..*    
0040 99A3A840 83888199 8183A385 99A24B40 *rty characters. |...@..........K@*    
0050 E38889A2 4089A240 8140A2A3 99899587 *This is a string|....@..@.@......*    
0060 40A689A3 88408696 99A3A840 83888199 * with forty char|@....@.....@....*    
0070 8183A385 99A24B40                   *acters.         |......K@        *

Figure 2. SOCKAPI trace record.

====================================================================00002403    
 MVS026    SOCKAPI   60050043  20:08:09.181354   READ Exit                      
                                                                                
HASID....0024     PASID....0024     SASID..0024     JOBNAME..EZASOKAS           
TCB......006E6A68 TIE......00006DF8 PLIST..00006E0C DUCB.....00000009 KEY..8   
ADSNAME..EZASOKAS SUBTASK..EZASOKAS                 TOKEN....7F6F3798 09902FB0  
LOCAL  PORT..11007     IPADDR ..9.67.113.58                               
REMOTE PORT..1040      IPADDR ..9.67.113.58                               
REQAREA..:  00006D90x                                          Addr..00006D90  
SOCKET...:  1                                                  Addr..00006B94  
NBYTE....:  120                                                Addr..00006B90  
BUF......:                                                     Addr..00006B96  
    +0000  E38889A2  4089A240  8140A2A3  99899587  | This is a string |        
    +0010  40A689A3  88408696  99A3A840  83888199  |  with forty char |        
    +0020  8183A385  99A24B40  E38889A2  4089A240  | acters. This is  |        
    +0030  8140A2A3  99899587  40A689A3  88408696  | a string with fo |        
    +0040  99A3A840  83888199  8183A385  99A24B40  | rty characters.  |        
    +0050  E38889A2  4089A240  8140A2A3  99899587  | This is a string |        
RETCODE..:  120 BYTES TRANSFERRED                              Addr..00006EB4  
====================================================================00002407

The packet trace, on the other hand, does not correlate well with the SOCKAPI trace option. The packet trace records data being sent or received between the TCP/IP stack and the network. The packet trace data has headers and the data can be segmented or packed.