Defining IMS-to-IMS TCP/IP connections for MSC

Defining IMS-to-IMS TCP/IP connections for MSC requires defining MSC and IMS Connect and enabling a minimally configured IMSplex at each end of an MSC link.

Except when defining the MSC physical link, the process for defining MSC in the two IMS systems is the same as it is for any MSC link, without regard to the use of TCP/IP as the physical link type.

These instructions assume a general understanding of the system definition process for IMS, MSC, and IMS Connect, as well as an understanding of how to enable and start an IMSplex.

To simplify the following steps, the instructions refer to two IMS installations: an IMS1 installation and an IMS2 installation. The installations are at separate geographical locations. The IMS1 installation includes an IMS system, IMS1, an IMS Connect instance, HWS1, and an IMSplex, PLEX1. Similarly, the IMS2 installation includes an IMS2, an HWS2, and a PLEX2.

To define an IMS-to-IMS TCP/IP connection for an MSC link between two IMS systems, complete the following steps outlined for IMS1 and IMS2.

Procedure

  1. If an IMSplex is not already enabled at the IMS1 installation, enable IMS1 for an IMSplex and bring up PLEX1 by starting instances of the Structured Call Interface (SCI) and Operations Manager (OM) components of the IMS Common Service Layer (CSL). The SCI instance must be in the same logical partition as IMS1.
  2. In IMS1, code the MSC definitions, including at least one physical link and one logical link.
    When coding the MSPLINK macro to define the MSC physical link, the following summarized values are used for the TCP/IP physical link type:
    Label field
    Defines the name of the physical link to IMS1. The physical link name is used when assigning logical links and when issuing commands against the physical link.
    LCLICON
    The name that HWS1 registers with SCI in PLEX1. This name is also specified on the MEMBER parameter of the IMSPLEX substatement on MSC configuration statement for HWS1.
    LCLPLKID
    The ID of the MSC configuration statement that defines the MSC physical link to HWS1. This value must match the value specified on the LCLPLKID keyword of the MSC configuration statement for HWS1.
    NAME
    The IMS ID of IMS2.
    TYPE
    Specify TCPIP
  3. In HWS1, code the following required configuration statements:
    HWS
    To enable HWS1 to authenticate RACF® PassTickets sent by HWS2 on incoming TCP/IP connections, specify RACF=Y.
    TCPIP
    The value specified on either the PORT or PORTID keyword of the HWS1 TCPIP statement is also specified on the PORT keyword of the HWS2 RMTIMSCON statement.
    RMTIMSCON
    The RMTIMSCON statement defines the TCP/IP connection from HWS1 to HWS2.

    At a minimum, you must define the following keywords of the RMTIMSCON statement:

    ID
    Uniquely identifies this connection. The ID value must also be specified on the RMTIMSCON keyword on the HWS1 MSC configuration statement.
    IPADDR or HOSTNAME
    Identifies the internet address of the receiving IMS Connect instance
    PORT
    Identifies the port that the receiving IMS Connect instance uses for this connection. This value must match the value specified on either the PORT or PORTID keyword in the HWS2 TCPIP configuration statement.

    Optionally, specify the following additional parameters:

    APPL
    If HWS2 is configured to authenticate RACF PassTickets that are provided with incoming MSC TCP/IP connections, you must specify both the APPL and USERID parameters.
    PERSISTENT
    Although it is not required for MSC connections, code PERSISTENT=Y to avoid receiving a warning message when IMS Connect changes the default value during each start up.
    RESVSOC
    Reserves send sockets for the MSC logical links that use this TCP/IP connection. The corresponding receive sockets that are required by MSC logical links are not reserved.

    Specify a number equal to the maximum number of MSC logical links sessions that will use this physical link.

    In the PROCLIB configuration member for HWS1, the sum of all of the RESVSOC values in all RMTIMSCON statements cannot exceed the total value of the MAXSOC parameter in the TCPIP statement.

    USERID
    If HWS2 is configured to authenticate RACF PassTickets that are provided with incoming MSC TCP/IP connections, you must specify both the USERID and APPL parameters.
    MSC
    The MSC configuration statement defines the communications path from IMS1 to IMS2 through HWS1 and HWS2.

    All of the following keywords of the MSC statement are required:

    LCLPLKID
    Identifies the MSC statement that defines the physical link to HWS1. This value must match the value specified on the LCLPLKID parameter of the MSPLINK system definition macro that defines the physical link to IMS1. HWS2 specifies this value on the RMTPLKID parameter of the MSC statement.
    RMTPLKID
    The ID of the MSC statement that defines the physical link to HWS2. The value must match the value specified on both the LCLPLKID parameter of the MSC statement of HWS2 and the LCLPLKID parameter of the MSPLINK macro of IMS2.
    IMSPLEX=(MEMBER=imsconnectname , TMEMBER=(imsplexname)
    Joins HWS1 to PLEX1 to enable MSC communications between HWS1 and IMS1. If an IMSplex configuration statement joins IMS Connect to PLEX1 already, the IMSplex substatement can be omitted from the MSC statement.
    LCLIMS
    The IMS ID of IMS1 as registered with SCI in the IMSplex. The IMS ID must be enclosed in parentheses, for example: LCLIMS=(IMS1).
    RMTIMS
    The IMS ID of IMS2 as registered with SCI in PLEX2.
    RMTIMSCON
    The name of the connection between IMS1 and IMS2 that is to be used for this MSC physical link, as defined on the ID parameter of the RMTIMSCON statement of IMS1.
  4. If an IMSplex is not already enabled at the IMS2 installation, enable IMS2 for an IMSplex and bring up PLEX2 by starting instances of the SCI and OM CSL components. The SCI instance must be in the same logical partition as IMS2.
  5. In IMS2, code the MSC definitions.
    When coding the MSPLINK macro to define the MSC physical link, the following values are specific to the TCP/IP physical link type:
    Label field
    Defines the name of the physical link to IMS2. The physical link name is used when assigning logical links and when issuing commands against the physical link.
    LCLICON
    The name that HWS2 registers with SCI in PLEX2. This name is also specified on the MEMBER parameter of the IMSPLEX substatement on MSC configuration statement for HWS2.
    LCLPLKID
    The ID of the MSC configuration statement that defines the MSC physical link to HWS2. This value must match the value specified on the LCLPLKID keyword of the MSC configuration statement for HWS2.
    NAME
    The IMS ID of IMS1.
    TYPE
    Specify TCPIP
  6. In HWS2, code the following required configuration statements:
    HWS
    This configuration statement is required by IMS Connect.

    To enable HWS2 to authenticate RACF PassTickets sent by HWS1 on incoming TCP/IP connections, specify RACF=Y.

    TCPIP
    This configuration statement is required by IMS Connect.

    The value specified on either the PORT or PORTID keyword of the HWS2 TCPIP statement is also specified on the PORT keyword of the HWS1 RMTIMSCON statement.

    RMTIMSCON
    The RMTIMSCON statement defines the TCP/IP connection from HWS2 to HWS1.

    At a minimum, you must define the following keywords of the RMTIMSCON statement:

    ID
    Uniquely identifies this connection. The ID value must also be specified on the RMTIMSCON keyword on the HWS2 MSC configuration statement.
    IPADDR or HOSTNAME
    Identifies the internet address of the receiving IMS Connect instance
    PORT
    Identifies the port that HWS1 uses for this connection. This value must match the value that is specified on either the PORT or PORTID keyword in the HWS1 TCPIP configuration statement.

    Optionally, specify the following additional parameters:

    APPL
    If HWS1 is configured to authenticate RACF PassTickets that are provided with incoming MSC TCP/IP connections, you must specify both the APPL and USERID parameters.
    PERSISTENT
    Although it is not required for MSC connections, code PERSISTENT=Y to avoid receiving a warning message when IMS Connect changes the default value during each start up.
    RESVSOC
    Reserves send sockets for the MSC logical links that use this TCP/IP connection. The corresponding receive sockets that are required by MSC logical links are not reserved.

    Specify a number equal to the maximum number of MSC logical links sessions that will use this physical link.

    In the configuration member for HWS2, the sum of all of the RESVSOC values in all RMTIMSCON statements cannot exceed the total value of the MAXSOC parameter in the TCPIP statement.

    USERID
    If HWS1 is configured to authenticate RACF PassTickets that are provided with incoming MSC TCP/IP connections, you must specify both the USERID and APPL parameters.
    MSC
    For HWS2, the MSC configuration statement defines the communications path from IMS2 to IMS1 through HWS2 and HWS1.

    All of the following keywords of the MSC statement are required:

    LCLPLKID
    Identifies the MSC statement that defines the physical link to HWS2. This value must match the value specified on the LCLPLKID parameter of the MSPLINK system definition macro that defines the physical link to IMS2. HWS1 specifies this value on the RMTPLKID parameter of the MSC statement.
    RMTPLKID
    The ID of the MSC statement that defines the physical link to HWS1. The value must match the value specified on both the LCLPLKID parameter of the MSC statement of HWS1 and the LCLPLKID parameter of the MSPLINK macro of IMS1.
    IMSPLEX=(MEMBER=imsconnectname , TMEMBER=(imsplexname)
    Joins HWS2 to PLEX2 to enable MSC communications between HWS2 and IMS2. If an IMSplex configuration statement joins IMS Connect to PLEX2 already, the IMSplex substatement can be omitted from the MSC statement.
    LCLIMS
    The IMS ID of IMS2 as registered with SCI in the IMSplex. The IMS ID must be enclosed in parentheses, for example: LCLIMS=(IMS2).
    RMTIMS
    The IMS ID of IMS1 as registered with SCI in PLEX1.
    RMTIMSCON
    The name of the connection between IMS2 and IMS1 that is to be used for this MSC physical link, as defined on the ID parameter of the RMTIMSCON statement of IMS2.
After the MSC links and TCP/IP connections have been defined and both IMSplexes have been started, start communications between IMS1 and IMS2. To start communications, issue either the IMS type-1 command /RSTART LINK or the IMS type-2 command UPDATE MSLINK NAME(linkname) START(COMM) in each system.