OSI/TS Management Programming Manual

ALTER SERVICE Command
Commands and Responses
5–50 056786 Tandem Computers Incorporated
ZALT-CLASS
is the alternative protocol class used if the class specified in ZCLASS is not
supported by the remote system. If ZCLASS has the value ZOS4-VAL-CLASS-
0, then ZALT-CLASS is not applicable. The values for this field are the same
as for ZCLASS:
ZOS4-VAL-CLASS-0
ZOS4-VAL-CLASS-1
ZOS4-VAL-CLASS-2
ZOS4-VAL-CLASS-3
ZOS4-VAL-CLASS-4
This parameter is not applicable if the preferred class is 0. Only one
alternative class may be specified. The following table defines the valid
combinations of preferred class and alternative classes.
Preferred Class Alternative Classes
0 not applicable
1 0 or 1
2 0 or 2
3 0 or 1 or 2 or 3
4 0 or 1 or 2 or 3 or 4
The default value of the parameter is the value of the class token.
ZTPDU-SIZE
is the maximum length of a transport protocol data unit (TPDU) in bytes.
Acceptable values are 128, 256, 512, 1024, 2048, 4096, and 8192 bytes. The
values 4096 and 8192 are valid only when ZCLASS is 1, 2, 3, or 4. For X.25
subnetworks: OSI/TS will adjust the value of ZTPDU-SIZE to not exceed the
value of the X25AM SYSGEN attribute MAXIOSIZE. Use the STATUS SU
command to determine the actual ZTPDU-SIZE used when the connection
was established.The default value is 512 bytes.
ZXSUM
specifies whether the checksum field is added to each TPDU. This field is
applicable only for protocol class 4 communication. If set to ZSPI-VAL-TRUE,
the checksum field is added; if set to ZSPI-VAL-FALSE, the checksum is not
added. The default value is ZSPI-VAL-TRUE.
ZEXT-FRMT
controls the use of extended format for the credit and sequence number of the
TPDUs. This field is applicable only for protocol class 2, 3, or 4
communication. If set to ZSPI-VAL-TRUE, the extended format is used; if set
to ZSPI-VAL-FALSE, the normal format is used. The default value is ZSPI-
VAL-FALSE.