
>>-SESSIONS(name)--GROUP(groupname)--+-------------------+------>
'-DESCRIPTION(text)-'
.-PROTOCOL(APPC)--| Attributes for APPC sessions |---------.
>--+----------------------------------------------------------+-->
+-PROTOCOL(LU61)--| Attributes for MRO and LU61 sessions |-+
'-PROTOCOL(EXCI)--| Attributes for EXCI sessions |---------'
.-AUTOCONNECT(NO)--. .-BUILDCHAIN(YES)-.
>--+------------------+--+-----------------+-------------------->
+-AUTOCONNECT(ALL)-+ '-BUILDCHAIN(NO)--'
'-AUTOCONNECT(YES)-'
.-NEPCLASS(0)---------.
>--CONNECTION(connection)--+---------------------+-------------->
'-NEPCLASS(tranclass)-'
.-RECEIVESIZE(4096)---. .-RECOVOPTION(SYSDEFAULT)--.
>--+---------------------+--+--------------------------+-------->
'-RECEIVESIZE(number)-' +-RECOVOPTION(CLEARCONV)---+
+-RECOVOPTION(NONE)--------+
+-RECOVOPTION(RELEASESESS)-+
'-RECOVOPTION(UNCONDREL)---'
.-RELREQ(NO)--. .-SENDSIZE(4096)---.
>--+-------------+--+------------------+------------------------>
'-RELREQ(YES)-' '-SENDSIZE(number)-'
.-SESSPRIORITY(0)--------. .-USERAREALEN(0)------.
>--+------------------------+--+---------------------+---------->
'-SESSPRIORITY(priority)-' '-USERAREALEN(number)-'
>--+----------------+------------------------------------------><
'-USERID(userid)-'

Attributes for APPC sessions
.-MAXIMUM(1,0)-----------.
|--+------------------------+--+--------------------+-----------|
'-MAXIMUM(value1,value2)-' '-MODENAME(modename)-'

Attributes for MRO and LU61 sessions
.-DISCREQ(NO)--. .-IOAREALEN(0,0)-----------.
|--+--------------+--+--------------------------+--------------->
'-DISCREQ(YES)-' '-IOAREALEN(value1,value2)-'
>--+--------------------+--------------------------------------->
'-NETNAMEQ(netnameq)-'
.--------------------------.
V | .-RECEIVEPFX(<)------. .-SENDPFX(>)------.
>--+---+-RECEIVECOUNT(number)-+-+--+--------------------+--+-----------------+-+--|
| '-SENDCOUNT(number)----' '-RECEIVEPFX(prefix)-' '-SENDPFX(prefix)-' |
'-SESSNAME(sessname)--+-RECEIVECOUNT(1)-+-----------------------------------'
'-SENDCOUNT(1)----'

Attributes for EXCI sessions
.-IOAREALEN(0,0)-----------.
|--+--------------------------+--RECEIVECOUNT(number)----------->
'-IOAREALEN(value1,value2)-'
.-RECEIVEPFX(<)------.
>--+--------------------+---------------------------------------|
'-RECEIVEPFX(prefix)-'
- AUTOCONNECT({NO|YES|ALL})
- specifies how connections are to be established. What you have to specify
for LU6.1 and APPC sessions is discussed below:
- APPC sessions
- For a VTAM®-connected
system that has AUTOCONNECT(YES) or (ALL) on the connection definition:
- NO
- CICS® does
not attempt to bind any sessions when the connection is established. However,
one or more user sessions may be allocated as part of any ACQUIRE CONNECTION
processing which takes place.
- YES or ALL
- A contention-winner session is established (that is, BIND is performed)
during CICS initialization, or when communication with VTAM is started using
the CEMT SET VTAM OPEN command. If the connection cannot be made at this time
because the remote system is unavailable, the link must be subsequently acquired
using the CEMT SET CONNECTION(sysid) INSERVICE ACQUIRED command, unless the
remote system becomes available in the meantime and itself initiates communications.
AUTOCONNECT(ALL)
should not be specified for sessions to other CICS systems, because this can
caused a bind race.
For a VTAM-connected system that has AUTOCONNECT(NO) on
the CONNECTION definition:
- ALL
- All sessions, not just contention winners, are established when the connection
is acquired by issuing CEMT SET CONNECTION(name) ACQUIRED, or when the remote
system itself initiates communication.
- NO
- CICS does not attempt to bind any sessions when the connection is established.
However, one or more user sessions may be allocated as part of any ACQUIRE
CONNECTION processing that takes place.
- YES
- Contention-winner sessions are established when the connection is acquired
by issuing CEMT SET CONNECTION(sysid) ACQUIRED, or when the remote system
itself initiates communication.
- LU6.1 sessions
- Specify AUTOCONNECT(YES) on the SESSIONS if you want the connection to
be established at initialization or CEDA install.
Specify AUTOCONNECT(NO)
on the SESSIONS if you do not want the connection to be established at initialization
or CEDA installation.
- BUILDCHAIN({YES|NO})
- specifies whether CICS is to perform chain assembly before passing the
input data to the application program.
- NO
- Any TIOA received by an application program from this logical unit contains
one request unit (RU).
- YES
- Any terminal input/output area (TIOA) received by an application program
from this logical unit contains a complete chain.
- CONNECTION(connection)
- specifies the name of the connection definition that you want to use with
this session definition. The name can be up to four characters in length.
Acceptable characters:A-Z 0-9 $ @ #
Unless
you are using the CREATE command, any lowercase characters you enter are converted
to uppercase. |
Note that
the CONNECTION definition must be in the same GROUP as the SESSIONS definition.
- DESCRIPTION(text)
- You can provide a description of the resource you are defining in this
field. The description text can be up to 58 characters in length. There are
no restrictions on the characters that you can use. However,
if you use parentheses, ensure that for each left parenthesis there is a matching
right one. If you use the CREATE command, for each single apostrophe in the
text, code two apostrophes.
- DISCREQ({NO|YES})
- specifies
whether disconnect requests are to be honored. DISCREQ applies
to LUTYPE6.1 ISC sessions, but not to MRO sessions where CICS is not dealing
with VTAM devices.
DISCREQ
does not apply to APPC (LUTYPE6.2) sessions. When APPC is used, individual
sessions are acquired as transactions need them, then are subsequently freed.
Because it is possible to have multiple sessions between APPC logical units,
there should never be a problem of one request holding up another. It is not
possible to disconnect an individual APPC session; instead, you can issue
a CEMT SET CONNECTION RELEASED command.
- NO
- CICS is not to honor a disconnect request for a VTAM device.
- YES
- CICS is to honor a disconnect request for a VTAM device, and issue a VTAM
CLSDST macro instruction to terminate the VTAM session with that logical unit.
CESF LOGOFF or GOODNIGHT commands issued from the terminal also cause
disconnection if you specify DISCREQ(YES).
- GROUP(groupname)
- Every resource definition must have a GROUP name. The resource definition
becomes a member of the group and is installed in the CICS system when the
group is installed.
Acceptable characters:A-Z 0-9 $ @ #
Any
lower case characters you enter are converted to upper case. |
The GROUP name can be up to eight characters in length. Lowercase
characters are treated as uppercase characters. Do not use group names beginning
with DFH, because these characters are reserved for use by CICS.
- INSERVICE
- This attribute is obsolete, but is supported to provide compatibility
with earlier releases of CICS. For more information, see Obsolete attributes.
- IOAREALEN({0|value1},{0|value2})
- specifies the length, in bytes, of the terminal input/output area to be
used for processing messages transmitted on the MRO link.
- value1
- value1 specifies the minimum size of a terminal input/output
area to be passed to an application program when a RECEIVE command is issued.
- value2
- If value2 is not specified, or is less than value1,
it defaults to the value of value1.
You can specify value2 as
greater than or equal to value1. In this case, when the
size of an input message exceeds value1, CICS uses a terminal input/output
area (TIOA) value2 bytes long.
When
a transaction is attached on an MRO link, CICS uses a TIOA that is long enough
to contain the initial input message.
Otherwise, if the input message
size also exceeds value2, the node abnormal condition program
sends an exception response to the terminal.
You can waste both real and virtual storage by specifying
an IOAREALEN value that is too large for most messages transmitted on your
MRO link. On the other hand, if you specify an IOAREALEN value that is either
zero or smaller than most of your messages, excessive FREEMAIN and GETMAIN
activity may occur. This results in additional processor requirements.
- MAXIMUM({1|value1},{0|value2}) (APPC
only)
- specifies the maximum number of sessions that are to be supported for
the modeset. Value1 must be greater than or equal to value2.
- 1|value1
- The maximum number of sessions in the group. This value can be in the
range 1 through 999. The default is 1.
- 0|value2
- The maximum number of sessions that are to be supported as contention
winners. This value can be in the range 0 to 999. The default is 0. Note that
this operand has no meaning for a single session connection. (For further
information on the effects of the MAXIMUM option, see the CICS Intercommunication Guide.)
SNA allows some resources (for example, switched lines)
to be defined in the network as limited resources. At bind time, VTAM
indicates to CICS whether the bind is over a limited resource. When a CICS
task frees a session across a limited resource, CICS unbinds the session if
no other task wants to use it.
If the sessions are to use limited resources,
specify MAXIMUM(value1,0).
This causes any unbound session to be reset so that either side can then bind
it as a winner when it is next required. For more information on limited resources,
see the CICS Intercommunication
Guide.
- MODENAME(modename) (APPC
only)
- specifies the name that identifies a group of sessions for use on an APPC
connection. The name can be up to eight characters in length, and must be
the name of a VTAM LOGMODE entry defined to VTAM. It must not be the reserved
name SNASVCMG. If you omit the modename it defaults to blanks. See the CICS Intercommunication Guide for
more information about VTAM modenames.
The MODENAME must be unique for each
group of sessions defined for any one intersystem link. That is, the MODENAME
must be unique among the SESSIONS definitions related to one CONNECTION definition.
It is passed to VTAM as the LOGMODE name.
- NEPCLASS({0|tranclass})
- specifies the transaction class for the node error program. This value
acts as the default.
- 0
- This results in a link to the default node error program module.
- tranclass
- The transaction class for the (nondefault) node error program module.
The value can be in the range 1 through 255. For programming information about
the node error program, see the CICS Customization
Guide.
The NEPCLASS attribute is ignored
for SNASVCMGR sessions.
- NETNAMEQ(netnameq)
- specifies the name by which the remote IMS™ system knows this particular session.
This is used for CICS-IMS sessions. The name can be up to eight characters
in length. The acceptable characters are: A-Z 0-9 $ @ # . / - _ % &
¢ ? ! : | " = ¬ , ; < and >. Lowercase characters are converted to uppercase
except when using the CREATE command.
- OPERID
- This attribute is obsolete, but is supported to provide compatibility
with earlier releases of CICS. For more information, see Obsolete attributes.
- OPERPRIORITY
- This attribute is obsolete, but is supported to provide compatibility
with earlier releases of CICS. For more information, see Obsolete attributes.
- OPERRSL
- This attribute is obsolete, but is supported to provide compatibility
with earlier releases of CICS. For more information, see Obsolete attributes.
- OPERSECURITY
- This attribute is obsolete, but is supported to provide compatibility
with earlier releases of CICS. For more information, see Obsolete attributes.
- PROTOCOL({APPC|LU61|EXCI})
- specifies the type of protocol that is to be used for an intercommunication
link (ISC or MRO).
- APPC (LUTYPE6.2)
- Advanced program-to-program communication (APPC) protocol. Specify this
for CICS-CICS ISC.
- EXCI
- The external CICS interface. Specify this to indicate that the sessions
are for use by a non-CICS client program using the external CICS interface.
- LU61
- LUTYPE6.1 protocol. Specify this for CICS-CICS ISC, for CICS-IMS, or for
MRO.
- RECEIVECOUNT(number)
- For MRO, and
VTAM LU6.1 sessions, and for sessions with EXCI clients, specifies the number
of receive sessions; that is, sessions that normally receive before
sending:
- MRO receive sessions (including sessions with EXCI clients) always receive
before sending
- VTAM LU6.1 receive sessions normally receive before sending, but may send
before receiving when there is a shortage of suitable send sessions
The number of receive sessions you can specify depends upon the length
of the prefix specified in the RECEIVEPFX attribute:
- If you use the default receive prefix (<), or your own 1-character
prefix, you can specify 1 through 999 receive sessions
- If you use a 2-character prefix, you can specify 1 through 99 receive
sessions.
You should also ensure that the value specified matches the number of
send sessions in the partner system:
- If the partner is another CICS system, the value should match the SENDCOUNT
specified in the partner system
- If the partner is an EXCI client, you cannot specify the number of send
session in the partner. However, there is an upper limit of 100 send sessions
in an EXCI address space. When this limit is reached, IRP rejects further
requests for a session with SYSTEM_ERROR reason code 608.
If you do not specify the RECEIVECOUNT attribute, there are no
receive sessions
- RECEIVEPFX({<|prefix})
- specifies a 1-or 2-character prefix that CICS is to use as the first one
or two characters of the receive session names (the names of the terminal
control table terminal entries (TCTTEs) for the sessions).
Prefixes
must not cause a conflict with an existing connection or terminal name.
- < (MRO and EXCI sessions)
- For MRO and EXCI sessions, if you do not specify your own receive
prefix, CICS enforces the default prefix—the less-than symbol (<), which
is used in conjunction with the receive count to generate receive session
names.
CICS creates the last three characters of the session names. The
acceptable characters are A-Z 1-9. These 3-character identifiers begin with
the letters AAA, and continue in ascending sequence until the number of session
entries reaches the limit set by the RECEIVECOUNT value. Note that receive
session names are generated after the send sessions, and they follow
in the same sequence.
For example, if the last session name generated
for the send sessions is >AAJ, using the default sendprefix
(>) CICS generates the receive session names as <AAK, <AAL,
<AAM, and so on. (This method of generation of session identifiers is the
same as for APPC sessions, except for the initial prefix symbol.)
If
you use more than 46656 sessions (<AAA to <999), CICS allocates the
next range of AAA< to 999<, again in a similar manner to APPC sessions.
A
region with more than 46656 sessions might not perform well. You should consider
the alternative of increasing the number of CICS regions.
Although you
can define up to 93312 MRO sessions there is a current restriction that prevents
you from attempting to acquire more than 65535 sessions in one attempt. This
might occur during CICS start up or for a CEDA install for more than 65536
sessions if ALL the partner regions are up and running. Further sessions
can be acquired later.
Note: If you specify your own prefix, CICS generates
the session names in the same way as it does for LUTYPE6.1 sessions.
- prefix (LUTYPE6.1 sessions)
- If the sessions are on LUTYPE6.1 ISC connections, you must specify a 1-or
2-character prefix. Do not use the default < symbol for LUTYPE6.1 sessions.
For LUTYPE6.1 sessions (and MRO if you specify your own 1-or 2-character
prefix), CICS generates session names by appending a number to the prefix,
either in the range 1 through 99, or 1 through 999. The number begins with
1 and is incremented by 1 until the specified RECEIVECOUNT is reached.
- RECEIVESIZE({4096|number})
- specifies the maximum VTAM request unit (RU) size that these sessions
are capable of receiving. The value must be between 1 and 30720 for LU61 sessions,
or 256 and 30720 for APPC sessions. The default is 4096.
The value
specified is transmitted to the connected logical unit. This value may be
rounded down by CICS, depending on what value you specified, because the value
must be transmitted in an architected form. The value may be negotiated down
still further at BIND time.
If CICS is the secondary LU session, this
indicates the maximum VTAM request unit (RU) size that these sessions are
capable of sending.
- RECOVNOTIFY
- This attribute is obsolete, but is supported to provide compatibility
with earlier releases of CICS. For more information, see Obsolete attributes.
- RECOVOPTION({SYSDEFAULT|CLEARCONV| RELEASESESS|UNCONDREL|NONE})
- This option applies to the recovery of sessions in a CICS region running
with VTAM persistent sessions, or with XRF.
VTAM persistent sessions:
In a CICS region running with persistent session support, this option specifies
how you want CICS to recover the session, and return the terminal to service
on system restart within the persistent session delay interval.
XRF:
In a CICS region running with XRF support, this option specifies how you want
CICS to recover the session, and return the terminal to service after an XRF
takeover.
For all recovery options other than NONE, if the action taken
is a VTAM UNBIND, the UNBIND is followed by a VTAM SIMLOGON.
- CLEARCONV
- VTAM persistent sessions: CLEARCONV is not supported for APPC sessions.
It defaults to SYSDEFAULT.
XRF: If AUTOCONNECT(YES) is specified,
the session is restarted. If AUTOCONNECT(NO) is specified, the session is
unbound.
- NONE
- VTAM persistent sessions: In a CICS region running with persistent
sessions support, this specifies that the session is not to be recovered at
system restart within the persistent session delay interval: in effect, the
sessions on the modegroup have no persistent sessions support. LU6.2 sessions
are unbound and the modegroup CNOS value is reset to zero. After system restart,
the session is reconnected automatically if you specify AUTOCONNECT(YES).
XRF: In a CICS region running with XRF support, this specifies
that the logon state is not tracked by the alternate system, and the terminal
session is not automatically recovered after a takeover; in effect, the terminal
has no XRF support. After takeover, the terminal is reconnected automatically
by the alternate system, if you specify AUTOCONNECT(YES).
- RELEASESESS
- VTAM persistent sessions: RELEASESESS is not supported for APPC
sessions. It defaults to SYSDEFAULT.
XRF: If AUTOCONNECT(YES) is
specified, the session is restarted. If AUTOCONNECT(NO) is specified, the
session is unbound.
- SYSDEFAULT
- VTAM persistent sessions: In a CICS region running with persistent
sessions support, this specifies that CICS is to select the optimum procedure
to recover a session on system restart within the persistent session delay
interval, depending on the session activity and on the characteristics of
the terminal.
Although sessions are recovered, any transactions in-flight
at the time of the failure are abended and not recovered. Transactions are
also abended if the recovered session is being used by another CICS region
over an APPC connection.
CICS recovers the session with the least possible
impact, in one of the following ways:
- If the session was not busy at the time that CICS failed, no action is
required.
- If the session was busy at the time that CICS failed, CICS issues a DEALLOCATE(ABEND)
(equivalent to an EXEC CICS ISSUE ABEND) for the APPC conversation in progress
at the time of the failure.
- If neither of the above applies, the session is unbound.
XRF: If AUTOCONNECT(YES) is specified, the session is
restarted. If AUTOCONNECT(NO) is specified, the session is unbound.
- UNCONDREL
- Requires CICS to send an UNBIND request to release the active session.
The UNBIND is sent whether or not the session was busy at the time of system
restart (in the case of persistent sessions support) or takeover (in the case
of XRF).
- RELREQ({NO|YES})
- specifies whether CICS is to release the logical unit upon request by
another VTAM application program.
- SENDCOUNT(number)
- For MRO, and
VTAM LU6.1 sessions only, specifies the number of send sessions; that
is, sessions that normally send before receiving:
- MRO send sessions always send before receiving
- VTAM LU6.1 send sessions normally send before receiving, but may receive
before sending when there is a shortage of suitable receive sessions
The number of send sessions you can specify depends upon the length
of the prefix specified in the SENDPFX attribute:
- If you use the default send prefix (>), or your own 1-character prefix,
you can specify 1 through 999 send sessions
- If you use a 2-character prefix, you can specify 1 through 99 send sessions.
You should also ensure that the value specified matches the number of
receive sessions in the partner system:
- If the partner is another CICS system, the value should match the RECEIVECOUNT
specified in the partner system
If you do not specify the SENDCOUNT attribute, there are no send
sessions. Do not specify the SENDCOUNT attribute when the partner is an EXCI
client
- SENDPFX({>|prefix})
- specifies a 1-or 2-character prefix that CICS is to use as the first one
or two characters of the send session names (the names of the terminal control
table terminal entries (TCTTEs) for the sessions).
Prefixes must not cause a conflict with
an existing connection or terminal name.
- > (MRO sessions)
- For MRO sessions, if you do not specify your own send prefix, CICS enforces
the default prefix—the greater-than symbol (>), which is used in conjunction
with the send count to generate send session names.
CICS creates the last
three characters of the session names from the alphanumeric characters A through
Z, and 1 through 9. These 3-character identifiers begin with the letters AAA,
and continue in ascending sequence until the number of session entries reaches
the limit set by the SENDCOUNT value.
For example, using the default
prefix (>), CICS generates session names as >AAA, >AAB, >AAC, and so on. If
you use more than 46656 sessions (>AAA to >999), CICS allocates the next range
of AAA> to 999>. (This method of generation of session identifiers is
the same as for APPC sessions, except for the initial symbol.)
A region
with more than 46656 sessions might not perform well. You should consider
the alternative of increasing the number of CICS regions.
Although you
can define up to 93312 MRO sessions there is a current restriction that prevents
you from attempting to acquire more than 65535 sessions in one attempt. This
might occur during CICS start up or for a CEDA install for more than 65536
sessions if ALL the partner regions are up and running. Further sessions
can be acquired later.
Note: If you specify your own prefix, CICS generates
the session names in the same way as it does for LUTYPE6.1 sessions.
- prefix (for LUTYPE6.1 sessions)
- If the sessions are on LUTYPE6.1 ISC connections, you must specify a 1-or
2-character prefix. Do not use the default > symbol for LUTYPE6.1 sessions.
For LUTYPE6.1 sessions (and MRO if you specify your own 1-or 2-character
prefix), CICS generates session names by appending a number to the prefix,
either in the range 1 through 99, or 1 through 999. The number begins with
1 and are incremented by 1 until the specified SENDCOUNT is reached.
- SENDSIZE({4096|number})
- specifies the maximum VTAM request unit (RU) size that these sessions
are capable of sending. The value must be between 1 and 30720 for LU61 sessions,
or between 256 and 30720 for APPC sessions. The default is 4096. The value
may be negotiated down at bind time. Increasing the value of SENDSIZE causes
more storage to be allocated for the session but may decrease the number of
physical messages sent between the two nodes.
If CICS is the secondary LU session,
this attribute indicates the maximum VTAM request unit (RU) size that these
sessions are capable of receiving. The value must be between 256 and 30720.
- SESSIONS(name)
- specifies the
name of this SESSIONS definition. The name can be up to eight characters in
length.
Acceptable characters:A-Z a-z 0-9 $ @ # . / - _ % & ¢ ? ! : | " = ¬ , ; < >
For information about entering mixed case information,
see Entering mixed case attributes. |
This name is used to identify the SESSIONS definition on
the CSD file. It is not used within the active CICS system.
- SESSNAME(sessname)
- specifies the
symbolic identification to be used as the local half of a session qualifier
pair in a CICS intercommunication parallel session. The name can be up to
four characters in length.
Acceptable characters:A-Z a-z 0-9 $ @ # . / - _ % & ¢ ? ! : | " = ¬ , ; < >
For information about entering mixed case information,
see Entering mixed case attributes. |
- SESSPRIORITY({0|priority})
- specifies the terminal priority. This decimal value (0 through 255) is
used in establishing the overall transaction processing priority. (Transaction
processing priority is equal to the sum of the terminal priority, transaction
priority, and operator priority; this must not exceed 255.)
- TRANSACTION
- This attribute is obsolete, but is supported to provide compatibility
with earlier releases of CICS. For more information, see Obsolete attributes.
- USERAREALEN({0|number})
- Specify the length, in bytes, of the user area for this session, in the
range 0 through 255. It should be made as small as possible. The TCT user
area is initialized to zeros when the session is installed.
The TCT user
area may be located above or below the 16Mb line in virtual storage. Where
it is located depends on the value of the TCTUALOC operand of the DFHSIT macro.
You
should ensure that this is specified correctly to allow successful operation
of any programs that are not capable of handling 31-bit addressing.
- USERID(userid)
- specifies a user identifier used for sign-on (SEC=YES or MIGRATE) and
referred to in security error messages, security violation messages, and the
audit trail. It must be a valid userid defined to the security manager, or
operators will be unable to sign on. All access to protected resources depends
on USERID.
This USERID
overrides a SECURITYNAME specified on the CONNECTION definition.
The
name can be up to eight characters in length.
Acceptable characters:A-Z 0-9 $ @ #
Unless
you are using the CREATE command, any lowercase characters you enter are converted
to uppercase. |