Change Mode Description (CHGMODD)

Parameters

Keyword	Description	Choices	Notes
MODD	Mode description	Name	Required, Key, Positional 1
COS	Class-of-service	Communications name, *SAME, #CONNECT, #BATCH, #INTER, #BATCHSC, #INTERSC	Optional
MAXSSN	Maximum sessions	1-512, *SAME	Optional
MAXCNV	Maximum conversations	1-512, *SAME	Optional
LCLCTLSSN	Locally controlled sessions	0-512, *SAME	Optional
PREESTSSN	Pre-established sessions	0-512, *SAME	Optional
MAXINPAC	Maximum inbound pacing value	1-32767, SAME, CALC	Optional
INPACING	Inbound pacing value	0-63, *SAME	Optional
OUTPACING	Outbound pacing value	0-63, *SAME	Optional
MAXLENRU	Maximum length of request unit	241-32767, SAME, CALC	Optional
DTACPR	Data compression	1-2147483647, SAME, NETATR, NONE, ALLOW, REQUEST, REQUIRE	Optional
INDTACPR	Inbound data compression	SAME, RLE, LZ9, LZ10, LZ12, NONE	Optional
OUTDTACPR	Outbound data compression	SAME, RLE, LZ9, LZ10, LZ12, NONE	Optional
SLE	Session level encryption	ALL, NONE, *SAME	Optional
TEXT	Text 'description'	Character value, SAME, BLANK	Optional

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Class-of-service (COS)

Specifies the path control network characteristics (represented by a class-of-service description) used by advanced peer-to-peer networking (APPN).

#CONNECT
#BATCH
#INTER
#BATCHSC
#INTERSC

class-of-service-name: Specify the class-of-service name.
Note: The class-of-service name will be ignored if using mode for APPC.

*SAME: The value does not change.

Maximum sessions (MAXSSN)

Specifies the maximum number of active sessions that are established for this mode. This number must be greater than or equal to the sum of the number of locally controlled sessions as specified on the Locally controlled sessions prompt (LCLCTLSSN) and the number of locally controlled sessions specified at the remote location.

maximum-number-of-sessions: Specify the maximum number of sessions.
Valid values range from 1 to 512.

*SAME: The value does not change.

Maximum conversations (MAXCNV)

Specifies the maximum number of conversations that can be established at the same time with the remote system. The maximum number of conversations is the sum of synchronous and asynchronous conversations; this value must be greater than or equal to the value specified by the Maximum sessions prompt (MAXSSN parameter). A synchronous conversation is a conversation where both the source and the target programs are communicating. An asynchronous conversation is a conversation where the source program has detached itself from the conversation, but data is still being read by the target program.

maximum-number-of-conversations: Specify the maximum number of conversations. Valid values range from 1 to 512.

*SAME: The value does not change.

Locally controlled sessions (LCLCTLSSN)

Specifies the minimum number of locally controlled sessions that must be active to establish this mode. This value must be less than or equal to the value specified in the Maximum sessions prompt (MAXSSN parameter).

locally-controlled sessions: Specify the number of locally-controlled sessions used as source sessions. Valid values range from 0 to 512.

*SAME: The value does not change.

Pre-established sessions (PREESTSSN)

Specifies the maximum number of locally-controlled sessions that are established when the mode is started. Additional sessions are established as required, up to the maximum number of locally-controlled sessions specified in the Maximum sessions prompt (MAXSSN parameter). This value must be less than or equal to the value specified in the Locally controlled sessions prompt (LCLCTLSSN parameter).

number-of-established-sessions: Specify the maximum number of concurrent locally-controlled sessions established when the mode is started. Valid values range from 0 to 512.

*SAME: The value does not change.

Maximum inbound pacing value (MAXINPAC)

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

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

*SAME: The value does not change.

*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.

Maximum length of request unit (MAXLENRU)

Specifies the maximum request unit (RU) length allowed.

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

*CALC: The system calculates the value to use.

maximum-request-unit-length

Specify a value, ranging from 241 through 32767 in bytes, for the maximum length of incoming request units.

Some 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 is in the Communications Configuration book, SC41-5401 book.

*SAME: The value does not change.

Data compression (DTACPR)

Specifies whether data compression is used.

*SAME: The value does not change.

*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 Inbound data compression and Outbound data compression prompts (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 on the Inbound data compression and Outbound data compression prompts (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 Inbound data compression and Outbound data compression prompts (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 Inbound data compression and Outbound data compression prompts (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).

Inbound data compression (INDTACPR)

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

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.

*SAME: The value does not change.

*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. LZ12 requires the most storage and processing time of the LZ algorithms; however, it compresses the data stream the most.

*NONE: No compression occurs.

Outbound data compression (OUTDTACPR)

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

*SAME: The value does not change.

*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. LZ12 requires the most storage and processing time of the LZ algorithms; however, it compresses the data stream the most.

*NONE: No compression occurs.

Session level encryption (SLE)

Specifies the desired level of session encryption.

*SAME: The value does not change.

*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 i5/OS is installed along with the Cryptographic Processor feature or the Cryptographic Processor-Commercial feature.