DCAM LINK Statement

The DCAM LINK statement defines each driver's DCAM connection to any other Entire Net-Work node. This statement is not required if ACCEPTUI=Y (Yes) is specified in the related DRIVER statement.


LINK Statement Format

The DCAM LINK statement has the following format:

LINK linkname DCAM  ACQUIRE=N|Y,-
                    ADJNODE=adjacent-node-name|link-name,-
                    BLOCKMSG=N|Y,-
                    COMPRMSG=N|Y,-
                    CONUDATA=connection-user-data|(none),-
                    LOGPW=logon-password|(none),-
                    LOGUDATA=logon-user-data|(none),-
                    MAXBLK=n|4096,-
                    MINCMP=n|6,-
                    PRONAME=partner-processor-name,-
                    PTNNAME=partner-name|link-name,-
                    RESTART=retry interval and number retries (i,n),-
                    STATBLK=N|Y,-
                    STATCMP=N|Y,-
                    SYSCODE=N|Y,-
                    WEIGHT=n|256

For more information about syntax conventions and rules used in this section, read Conventions.

LINK Statement Parameters

In the following syntax-example diagrams, default values are underlined. The underlined portion of the parameter keyword is the minimum abbreviation.

 
				  
ACQUIRE = {N|Y}

This optional parameter instructs the line driver either to acquire the connection to the partner application (Y), or to build a LINKBLK only for the partner application and not issue DCAM YOPNCON (N). The default is N (No).

 
				  
ADJNODE = {adjacent-node-name|link-name}

This parameter is required with a gateway link and specifies the node name that Entire Net-Work is to use for the adjacent node on the other side of the link.

 
				  
BLOCKMSG = {N|Y}

BLOCKMSG=Y (Yes) causes messages for this link to be blocked for transmission. The default value is N, no blocking.

 
				  
COMPRMSG = {N|Y}

COMPRMSG=Y (Yes) causes messages for this link to be compressed for transmission. The default value is N, no data compression.

 
				  
CONUDATA = {connection-user-data|(none)} 

This parameter allows you to specify the data to be sent with the connection request to the communication partner. The maximum length is 16; there is no default value.

The parameter must be set to the following value when communicating with VMS: X'FE0000004E4554524449', that is, X'FE000000'+ascii('NETRDI').

 
				  
LOGPW = {logon-password|(none)}

This optional parameter must match the password in LOGPASS used when connecting to the partner application. Otherwise, the connection request will be rejected. If you specify a value of "none" for the password, this parameter is ignored.

 
				  
LOGUDATA = {logon-user-data|(none)}

This parameter allows you to specify the data to be sent with a connection request from the communication partner. If the logon data does not match this value, the LOGON is rejected. The maximum length is 16; there is no default value.

 
				  
MAXBLK = {n|4096}

This optional parameter specifies the maximum transmission block size accepted by DCAM and the partner node, thus determining the size of messages sent to partner nodes. This value must not be higher than the MAXBLK parameter contained in the partner node's DRIVER statement.

The default of this parameter is 4096 bytes. The maximum value you can specify for front-end processors (FEPs) or data exchange controllers (DASTs) is 32767 bytes. The recommended value for LAN-based connections is 65520 bytes, which is also the maximum that can be specified for this parameter.

If you intend to send large messages over a DCAM link, set the MAXBLK parameter to the maximum value. If you receive error messages that read "unexpected response 0C30 from YSEND", choose increasingly smaller values for MAXBLK until the YSEND error messages disappear.

 
				  
MINCMP = {n|6}

This optional parameter specifies the smallest group of identical characters that will be compressed. Values less than 6 (the default) are not accepted.

 
				  
PRONAME = partner-processor-name

This required parameter provides the line driver with the TRANSDATA processor name of the session partner's processor.

 
				  
PTNNAME = { partner-name | link-name }

This optional parameter provides the line driver with the DCAM application name of the session partner. If the parameter is not specified, the default is the link name.

Depending on how the partner node is defined in the TRANSDATA network, the PTNNAME can be specified as an EBCDIC string (for example, definition of a VAX node as a station of the front end), or must be specified in ASCII (for example, a UNIX node connected by means of a LAN). In the latter, the hexadecimal notation must be used:

 
				  
ASCII 'SIN' -> X'53494E2020202020'

Note that the names will be printed in lower case in the DCAM line driver printout.

 
				  
RESTART = (i,n)

RESTART specifies the retry interval in seconds (i) and number of retries (n) to be used if you want Entire Net-Work to attempt to reconnect the link following a shutdown due to a failure. If RESTART is not specified or (i) is specified as zero, no retry is attempted. By specifying (n) as zero, an infinite number of retries can be requested.

The TIMER parameter on the NODE statement affects the RESTART parameter. (See the section Entire Net-Work NODE Statement .) The retry interval should not be less than the TIMER parameter, and should be a multiple of this value. If a retry interval other than zero is specified that is less than the value of the TIMER parameter, the TIMER value is used instead.

If a RESTART interval and count are also specified for the DCAM DRIVER statement, Software AG recommends that the link restart interval and retry count be coordinated with those values to ensure that a link restart follows a DCAM driver restart, if it occurs.

 
				  
STATBLK = { N | Y }

This optional parameter tells the transmission queue manager whether to keep blocking statistics for this link. The default value is N; blocking statistics are not kept. For this parameter to take effect, BLOCKMSG=Y must also be specified.

 
				  
STATCMP = { N | Y }

This optional parameter tells the transmission queue manager whether to keep compression statistics for this link. The default value is N; compression statistics are not kept. For this parameter to take effect, COMPRMSG=Y must also be specified.

 
				  
SYSCODE = { N | Y }

When this parameter is set to Y, messages along the link are sent and received with PROC=SYSCODE. This is required when the communication partner is Entire Net-Work VTAM via TRANSIT-CD. The default value is N.

 
				  
WEIGHT = { n | 256 }

If more than one path to a destination is available, the WEIGHT parameter allows a performance- or cost-based value to be assigned to each link in order to provide Entire Net-Work with information on which to base path selection. A higher value should be used for slower links and a lower value for faster links. Values may range 1 to 999999; the default is 256.

Example Procedures for an Entire Net-Work Node

Note that these procedures are similar to those in the section Running in BS2000/OSD Environments, except that the TCP/IP-specific component statements have been removed for the sake of clarity.

Note that there is no need to remove the TCP/IP statements from the delivered procedures, even if you do not have the optional TCP/IP driver installed.

Job START:

/SET-LOGON-PARAMETERS -
/    USER-ID  = *NO,-
/    ACCOUNT  = *NONE,-
/    JOB-CLASS = *STD,-
/    JOB-NAME  = NETWORK
/ASSIGN-SYSOUT -
/    TO = START.JNL
/CALL-PROC -
/    FROM-FILE = *LIB(LIB = WCPvrs.LIB,-
/            ELE = STARTP),-
/    PROC-PAR  = (DUMP = YES,-
/            ADALIB= &(ADALIB))
/    LOGGING   = *YES
ADARUN PROG=NETWRK,TARGETID=1234,IDTNAME=name,FORCE=N
ADARUN TASKCTGY=TP
/EOF
NODE SI01 BUFFERS=(128K,8K,1024K),REPLY=120,NT=128,LOG=N
DRIVER DCAM GOSIGNAL=Y,MAXBL=4096,APP=TRANSIT1
LINK LNK1 DCAM PRONAME=HOST,COMPR=N,MAXBLK=4096,ACQ=N
LINK LNK2 DCAM PRONAME=HOST,COMPR=N,MAXBLK=4096,ACQ=N
/EXIT-JOB -
/    MODE = NORMAL,-
/    SYS-OUT = NONE

Procedure STARTP:

/SET-PROCEDURE-OPTIONS -
/    IMPLICIT-DECLARATION   = *YES,-           &* For SDF-BASYS
/    LOGGING-ALLOWED        = *YES,-           &*
/    SYSTEM-FIL-CONTEXT     = *SAME-AS-CAL,-   &* For ADARUN
/    JV-REPLACEMENT         = *AFTER,-         &* Allow JV for ADALIB
/    ERROR-MECHANISM        = *SPIN-OFF        &* For SDF-BASYS
/BEGIN-PARAMETER-DECLARATION
/    DECLARE-PARAM -                           &* Used to form WCP
/       VERSION(INIT='571')                    &* library name.
/    DECLARE-PARAM -                           &* Adabas or WAL library.
/       ADALIB                                 &*
/    DECLARE-PARAM -                           &* Determines whether a dump
/       DUMP(INIT='NO')                        &* is created for errors.
/END-PARAMETER-DECLARATION
/
/MODIFY-JOB-OPTIONS -                          &* Log messages to the system
/    OPERATOR = *YES                           &* Console.
/
/MODIFY-TEST-OPTIONS -
/    DUMP = &DUMP
/
/CALL-PROC -
/    FROM-FILE = *LIB(LIB = WCP&VERSION..LIB, -
/                     ELE = NEWGEN), -
/   PROC-PAR  = (NET.PROTO.OUT)                &* Create the next generation
/                                              &* in this file group, then
/ASSIGN-SYSOUT -                               &* direct SYSOUT to it.
/    TO = NET.PROTO.OUT(+0)
/
/SHOW-JOB-STATUS
/
/SET-FILE-LINK -                               &* add WCP file link for BLS,
/    LINK-NAME = BLSLIB01, -
/    FILE-NAME = WCP&VERSION..LIB
/
/SET-FILE-LINK -                               &* add a file link for ADARUN.
/    LINK-NAME = DDLIB, -
/    FILE-NAME = &ADALIB
/
/  SEND-MSG -
/        TO = *OPERATOR,-
/        MSG = 'STARTING ENTIRE NET-WORK (V &VERSION)'
/
/  START-PROGRAM -
/    FROM      = *MODULE(LIB = &ADALIB, ELEM = ADARUN, PROG = ANY,-
/                             RUN-MOD = ADV(ALT-LIB = YES))        
/EXIT-PROC