CRTMODD (Create Mode Description)

CRTMODD Command syntax diagram

 

Purpose

The Create Mode Description (CRTMODD) command creates a mode description for advanced-program-to-program communications (APPC) devices. A mode description defines the session characteristics and number of sessions for a link between the local and remote locations.

APPC support uses Systems Network Architecture (SNA).

 

Required Parameters

MODD

Specifies the name of the mode description.

 

Optional Parameters

COS

Specifies the path control network characteristics used by advanced peer-to-peer networking (APPN) support.

Note:

This parameter is ignored if the communications line is not using APPN support.

class-of-service-name: Specify the class-of-service name in the mode description. Valid class-of-service names are shown below:

• #CONNECT
  
• #BATCH
  
• #INTER
  
• #BATCHSC
  
• #INTERSC

MAXSSN

Specifies the maximum number of active sessions that can be established for this mode. This number must be greater than or equal to the number of locally controlled sessions on the local system (as specified in the LCLCTLSSN parameter) plus the number of locally controlled sessions specified at the remote location.

8: The maximum number of active sessions is eight.

maximum-sessions: Specify a value, ranging from 1 through 512, for the maximum number of active sessions.

MAXCNV

Specifies the maximum number of active conversations allowed by the mode. The maximum number of active conversations is the sum of synchronous and asynchronous conversations; this value must be greater than or equal to the value specified by the MAXSSN parameter. A synchronous conversation is a conversation in which both the source and the target programs are communicating. An asynchronous conversation is a conversation in which the source program has detached from the conversation, but there is still data to be read by the target program.

8: Up to eight conversations are allowed.

maximum-conversations: Specify a value, ranging from 1 through 512, for the maximum number of conversations.

LCLCTLSSN

Specifies the minimum number of concurrent locally controlled sessions requested for this mode. This value must be less than or equal to the value specified in the MAXSSN parameter.

4: The minimum number of locally controlled sessions is 4.

locally-controlled-sessions: Specify a value, ranging from 0 through 512, for the number of locally controlled sessions.

PREESTSSN

Specifies the maximum number of locally controlled sessions established when the mode is started. Additional sessions are established when required up to the value specified in the MAXSSN parameter; this value must be less than or equal to the value specified in the LCLCTLSSN parameter.

0: No sessions are established when the mode is started.

pre-established-sessions: Specify a value, ranging from 0 through 512, used to specify the maximum number of concurrent locally controlled sessions established when the mode is started.

MAXINPAC

Specifies the maximum SNA pacing value used to schedule the incoming request units (RUs). Pacing is established by the receiving system to control the rate of transmission of the sending system to prevent the loss of data.

Note:

To ensure an optimum rate, the value *CALC is recommended.

*CALC: The system determines the value to use. The value is calculated to be 2*INPACING, which is two times the value specified on the INPACING parameter.

maximum-inbound-pacing: Specify a value, ranging from 1 through 32767 in RUs, for the maximum inbound pacing value.

INPACING

Specifies the Systems Network Architecture (SNA) pacing value used to schedule the incoming request units (RUs).

7: Character density is 16.7 characters per inch.

inbound-pacing-value: Specify a value, ranging from 0 through 63, as the limiting value.

OUTPACING

Specifies the SNA pacing value used for outgoing request units (RUs).

7: Character density is 16.7 characters per inch.

outbound-pacing-value: Specify a value, ranging from 0 through 63, for the limiting value.

MAXLENRU

Specifies the maximum request unit (RU) length (in bytes) allowed.

Note:

To ensure an optimum length, the value *CALC is recommended.

*CALC: The system determines the value to use.

maximum-length-request-unit: Specify a value, ranging from 241 through 32768 in bytes, for the maximum length of incoming request units. Other common values are:

SDLC lines:

256, 512, 1024, 2048

Token-Ring Network lines:

256, 512, 1024, 1985

X.25 (QLLC) lines:

247, 503, 1015

X.25 (ELLC) lines:

241, 497, 1009

More information about this parameter is in the Communications Configuration

book.

DTACPR

Specifies whether data compression is used.

*NETATR: The value from the DTACPR network attributes is used.

*NONE: Compression is not allowed on the session.

*ALLOW: Data compression is allowed on the session by the local system if requested by a remote system. The local system does not request compression.

If data compression is requested by the remote system, the data compression levels used by the session are the lower of the requested levels and the levels specified on the INDTACPR and OUTDTACPR parameters.

*REQUEST: Data compression is requested on the session by the local system. However, the request can be refused or changed to lower compression levels by the remote system. Data compression is allowed on the session if requested by the remote system. The requested compression levels for inbound and outbound data are the levels specified for the INDTACPR and OUTDTACPR parameters.

If data compression is requested by the remote system, the data compression levels used by the session are the lower of the requested levels and the levels specified on the INDTACPR and OUTDTACPR parameters.

*REQUIRE: Data compression is required on the session. If the remote system does not accept the local system's exact required levels of compression, the session is not established.

The data compression levels that the local system require are the levels specified on the INDTACPR and OUTDTACPR parameters.

line-speed: Specify the maximum line speed at which data is compressed. If the line speed of the link used by the session is less than or equal to this specified line speed, data compression is used for the session as if *REQUEST is specified. Otherwise, compression is used for the session as if *ALLOW is specified. Valid values range from 1 through 2147483647 in bits per second (bps).

INDTACPR

Specifies the desired level of compression for inbound data. No data compression occurs if DTACPR(*NONE) is specified.

Note:

Adaptive dictionary-based compression is a dynamic compression algorithm, similar to Lempel-Ziv, that compresses previously seen strings to 9-, 10-, and 12-bit codes. This algorithm is referred to as LZ in the following parameters.

*RLE: The Run Length Encoding (RLE) algorithm is used. RLE substitutes a 1- or 2-byte sequence in the data stream for each repeated occurrence of the same character. This algorithm requires no storage and less processing time than the other options.

*LZ9: The LZ algorithm with the 9-bit code for repeated substrings in the data stream is used. These codes refer to entries in a common dictionary, created as the data flows between the sender and receiver. The LZ algorithms require storage and extra processing time. The LZ9 requires the least storage and processing time of the LZ algorithms; however, it compresses the data stream the least.

*LZ10: The LZ algorithm with the 10-bit code for repeated substrings in the data stream is used. These codes refer to entries in a common dictionary, created as the data flows between the sender and receiver. The LZ algorithms require storage and extra processing time. The LZ10 table algorithm requires more storage and processing time than the LZ9, but less than the LZ12. The LZ10 compresses the data stream more than the LZ9, but less than the LZ12.

*LZ12: The LZ algorithm with the 12-bit code for repeated substrings in the data stream is used. These codes refer to entries in a common dictionary, created as the data flows between the sender and receiver. The LZ algorithms require storage and extra processing time. The LZ12 requires the most storage and processing time of the LZ algorithms; however, it compresses the data stream the most.

*NONE: No compression occurs.

OUTDTACPR

Specifies the desired level of compression for outbound data. No data compression occurs if DTACPR(*NONE) is specified.

*RLE: The Run Length Encoding (RLE) algorithm is used. RLE substitutes a 1- or 2-byte sequence in the data stream for each repeated occurrence of the same character. This algorithm requires no storage and less processing time than the other options.

*LZ9: The LZ algorithm with the 9-bit code for repeated substrings in the data stream is used. These codes refer to entries in a common dictionary, created as the data flows between the sender and receiver. The LZ algorithms require storage and extra processing time. The LZ9 requires the least storage and processing time of the LZ algorithms; however, it compresses the data stream the least.

*LZ10: The LZ algorithm with the 10-bit code for repeated substrings in the data stream is used. These codes refer to entries in a common dictionary, created as the data flows between the sender and receiver. The LZ algorithms require storage and extra processing time. The LZ10 table algorithm requires more storage and processing time than the LZ9, but less than the LZ12. The LZ10 compresses the data stream more than the LZ9, but less than the LZ12.

*LZ12: The LZ algorithm with the 12-bit code for repeated substrings in the data stream is used. These codes refer to entries in a common dictionary, created as the data flows between the sender and receiver. The LZ algorithms require storage and extra processing time. The LZ12 requires the most storage and processing time of the LZ algorithms; however, it compresses the data stream the most.

*NONE: No compression occurs.

SLE

Specifies the desired level of session encryption.

*NONE: No data is encrypted or decrypted.

*ALL: All data is encrypted before it is sent out to the network and is decrypted as it is received from the network.

Note:

The use of session level encryption requires that IBM Common Cryptographic Architecture Services for OS/400 is installed along with the Cryptographic Processor feature or the Cryptographic Processor-Commercial feature.

AUT

Specifies the authority given to users who do not have specific authority to the mode description, who are not on an authorization list, and whose user group has no specific authority to the mode description.

*LIBCRTAUT: The authority for the object is the same as the create authority for QSYS. The create authority for QSYS can be displayed by using the Display Library Description (DSPLIBD) command. If the create authority is changed with the Change Library (CHGLIB) command, the new authority does not affect existing objects.

*CHANGE: The user can perform all operations on the object except those limited to the owner or controlled by object existence authority and object management authority. The user can change and perform basic functions on the object. Change authority provides object operational authority and all data authority.

*ALL: The user can perform all operations except those limited to the owner or controlled by authorization list management authority. The user can control the object's existence, specify the security for the object, change the object, and perform basic functions on the object. The user also can change ownership of the mode description.

*USE: The user can perform basic operations on the mode description, such as running a program or reading a file. The user cannot change the mode description. *USE authority provides object operational authority, read authority, and execute authority.

*EXCLUDE: The user cannot access the mode description.

authorization-list-name: Specify the name of the authorization list used.

TEXT

Specifies the text that briefly describes the mode description. More information on this parameter is in Commonly used parameters.

*BLANK: Text is not specified.

'description': Specify no more than 50 characters of text, enclosed in apostrophes.

Example for CRTMODD

CRTMODD   MODD(MODE1)  COS(COSD1)
  TEXT('Mode using COSD1 Class-of-Service')

This command creates a mode, MODE1, that specifies class-of-service description COSD1.

Error messages for CRTMODD

*ESCAPE Messages

CPF261B

Mode description &1 not created due to errors.