The gateway is installed within an instance as service "G", and reads its parameters, as all servers do, from the profile file located in the profile directory in the SAP directory tree.
The following documentation describes parameters that could require modification in the event of gateway problems.
"Dynamic" means that the parameter can be changed while the system is running.

Specifies the maximum number of clients connected at a time. Note that the gateway regards an R/3 server as one single client.

Specifies the maximum number of connections that can be active at a time. This includes connections via LU6.2 to a HOST (R/2) and connections via TCP/IP.

Specifies the maximum number of gateway work processes that can be started.
This parameter only affects SNA connections.

Specifies the usage of the overflow area in % as of which the gateway slows down its clients, i.e. sends SYNC requests.

Determines how to start remote CPIC programs:

• REMOTE_SHELL : Start via remote shell
• REXEC : Start via rexec (UNIX only)
• DISABLED : Deactivate remote activation of programs

Remote programs to be started via remote shell always run under the "gateway" identification. If remote programs are started using rexec, they run under the identification defined by the parameters SAPUSERNAME and SAPPASSWORD.

(*) but only if changing the parameter affords increased security, thus REMOTE_SHELL -> DISABLED or REXEC -> DISABLED is allowed, whereas DISABLED -> REMOTE_SHELL or DIABLED -> REXEC is not.

Identification for starting remote CPIC programs via rexec.

Identification for starting remote CPIC programs via rexec.

File containing statements to start programs when the gateway starts. This is useful if CPIC/RFC server programs are always to run. When the gateway is restarted, these programs are thus started as well.

File syntax:

 Example of a file

; Syntax : local program [parameter...] or

; hostname program [parameter ...]

;

; Under NT the options ( starting with '-' )

; or strings containing a '/' must be placed in

; in quotation marks, for example

;

; hw1439 "/priv/cpict2" "-tp" cpict2 "-gwhost" p29290 "-gwserv" sapgw53

;

; start program locally ( registers using ID cpicsrc on gateway

; running locally and responds to service sapgw53 )

local /usr/sap/BIN/SYS/exe/run/cpicserver -tp cpicsrv -gwhost uw1033 -gwserv sapgw53

; start program remotely

hw1439 /usr/sap/BIN/SYS/exe/run/rfcserver -tp rfcsrv -gwhost uw1033 -gwserv sapgw53

Specifies whether the trace level of a CPIC or RFC connection should be transferred. In order to prevent misuse, you can use this parameter to prevent the trace level from being transferred within the gateway.
0 : Transfer trace level allowed
1 : Transfer trace level not allowed

Specifies the period (in seconds) after which a route to a remote gateway through which a CPIC connection is open is closed.

There are high availability solutions in which the IP addresses can move from one host to another. This means that the entries read when the gateway was started up may no longer be valid. In such cases, the current configuration must always be read using the "netstat" command when making the test for a "local" IP address. To activate this mechanism, set the profile parameter to 0.

Specifies the call path of the remote shell to start programs on other hosts. If the variable USER is defined in the environment, the value of this variable is transferred to the remote shell with the option -l <value>.

Specifies the maximum number of seconds for which an active connection cannot be used. If this time interval is exceeded, the connection is closed automatically. Only R/2 connections are checked.
If you set this parameter to 0, the connection is not closed automatically.
This parameter only affects SNA connections.

Specifies the maximum number of seconds for which an active connection can remain in the status DISCONNECT or DISCONNECTED. If this time interval is exceeded, the connection is closed by the gateway.
If you set this parameter to 0, such connections are not closed.

Specifies the maximum number of seconds for which a GW-GW connection can remain inactive. If this time interval is exceeded, the connection to the other gateway is closed. This is only the case if there is no active CPIC/RFC connection to this gateway.
If you set this parameter to 0, such connections are not closed.

Specifies the maximum time in seconds for which the gateway read process sleeps on the select.

Specifies the maximum time period (in seconds) before the system checks, using a ping, whether the partner is still alive when there is no data transfer across a CPIC connection.

Specifies the complete path of the side-info file. This parameter is passed on to the CPIC interface via putenv and defines the shell variable SIDE-INFO. The side-info file should be created in the Data Directory of the gateway instance, i.e. in /usr/sap/<instance name>/data.

Specifies the maximum wait time during connection setup. The wait time must not exceed the interval defined by the parameter (in seconds). Otherwise the connection setup is terminated with a timeout. This parameter is passed on to the CPIC interface via putenv and defines the shell variable CPIC_TIMEOUT.

Species the maximum wait time for setting up the connection with a registered program. The wait time must not exceed the interval defined by the parameter (in seconds). Otherwise the connection setup is terminated with a timeout.

Defines the type of load balancing for registered programs. The following values are permitted:

• 0 : No load balancing; the first free registered program is used.
• 1 : The program with the lowest counter is used. Every time a registered program is assigned a request, the counter is increased by one.
• 2 : The program with the lowest load is used. The load is determined as defined by profile parameter gw/reg_lb_ip.

Default value for the load of a server if its IP address cannot be found in the list.

Specifies the load value for an IP address or for a range of IP addresses. A host name can be entered in the place of an IP address. The gateway then determines the IP address for the host name.
When the registered program logs onto the gateway, the IP address is used to determine what the load of the IP address is. The system searches the list in the order specified by the profile parameter. This value is added to the load when this program receives a request. If the IP address is not found, the system uses the value defined by parameter gw/reg_lb_default. This ensures that a strong server is assigned more requests than a weaker server. A server that registers itself with the gateway receives as initial value the highest load of all servers with the same registration ID. If no servers are registered with this ID, or if no requests have been assigned to these servers, the value is 0.

List of IP addresses or host names The corresponding load is output with an equal sign after each IP address. The load is a weighting factor that specifies the strength of a particular server. The higher the value, the weaker the server. The maximum value is 1.

a.b.c.d=val1 e.f.g.*=val2 linux1=val3

Important: You can specify a range of IP addresses in the place of a single IP address, for example

gw/reg_lb_ip = 194.56.48.*=1 194.56.49.*=3

All servers from the 194.56.48 – network are highly efficient, the servers from the 194.56.49 network are somewhat weaker, and all other servers are extremely weak and should only be used infrequently.

Determines whether CPIC security calls (CMSCSP, CMSCSU, etc.) are called. The parameter setting depends on the security setting on the host.

 
If the host connection is implemented via UPIC, the security calls must not be called (parameter value must be 0).
This parameter only affects SNA connections.

(*) but only if changing the parameter affords increased security, thus 0 -> 1 is allowed, 1 -> 0 is not allowed.

These parameters can be used to protect external programs against being started. For more information, see the section on security.

(*) but only if changing the parameter affords increased security, thus 0 -> 1 is allowed, 1 -> 0 is not allowed.

File with security information

Determines the status of the gateway statistics after starting the gateway. The gateway statistics can be evaluated using the gateway monitor (gwmon or transaction SMGW), and can be changed dynamically.

Determines (provided this is supported by the R/2 System) that "non-conversational" mode is used, i.e. that the connection is established and closed for each dialog step of the CUA interface.
This makes sense when many connections are to be established to an R/2 System because (in CICS, for example) approximately 40 KB of information are held for each connection.

This parameter only affects SNA connections.

Poll raster setting for poll mode:
The system first polls gw/max_short_poll_no times with an interval of gw/gwwp_short_polling_time, then with an interval of gw/gwwp_long_polling_time.

The intervals are specified in milliseconds.

This parameter only affects SNA connections.

 This parameter only affects host connections via UPIC.

It determines the first 4 characters of the UTM login name. The gateway fills the remaining 4 characters with the work process number.

This parameter only affects SNA connections.

Determines whether a SIGN ON should be performed when the partner system is IMS.

This parameter only affects SNA connections.

IMS-SIGN-ON data. The following standard SIGN ON command is built up:

ON <user> <password>

The SIGN ON data may include up to two variable parts that must be specified with %s.

Note that the first %s pattern is replaced by the user name and the second %s is replaced by the password.

This parameter only affects SNA connections.

Maximum length of a data packet that can be sent to IMS using the send function.
This parameter only affects SNA connections.

This parameter determines whether the gateway can communicate with servers older than Release 3.0. For 3.0 installations, this parameter should be set to 0. In this case, errors that occur during connection setup can be returned to the caller directly, without trying the old procedure once more.

As of Release 4.6A, the default value of this parameter has been changed to 0.

In mixed installations, this parameter must have the value 1.

This parameter determines whether the gateway should communicate with the monitor locally or remotely.

• 0 : No monitor commands are accepted
• 1 : Only monitor commands from the local gateway monitor are accepted
• 2 : Monitor commands from local and remote monitors are accepted.

(*) but only if changing the parameter affords increased security, thus 2 -> 1 is allowed, 1 -> 2 is not allowed.

The following parameters are connected with SAP Gateway memory management, and must be changed in relation to the use of the gateway. Incorrect settings are the frequent cause of gateway error messages. These parameters and the permitted changes to them are described in detail to prevent errors in configuration:

There are a number of additional parameters that control the behavior of the SAP Gateway in conjunction with SNC (Secure Network Communication).