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Dan Yee, IBM TPF Development
In the previous issue of the TPF Systems Technical
Newsletter, I provided information about the new TPF
Transmission Protocol/Internet Protocol (TCP/IP) middleware that
was available with APAR PJ26161 on (PUT) 10. The middleware, which
consisted of Mapping of Airline Traffic over Internet Protocol
(MATIP) and IP Bridge support, enables you to migrate your message
traffic from a legacy network, using old equipment and protocols
such as the 3705 controller and synchronous link control (SLC), to
an IP network. APAR PJ26693 on PUT 11 enhances the MATIP and IP
Bridge support provided in PUT 10, so it is important that you take
note of the enhancements mentioned in this article if you are using
the middleware now or plan to do so in the future. Most of the
enhancements described in this article pertain only to MATIP
support, so those only associated with MATIP are referred to as
MATIP enhancements as opposed to MATIP and IP Bridge
enhancements.
Support of TPF TCP/IP Native Stack
The MATIP and IP Bridge support provided with APAR PJ26161 will
only run with TPF TCP/IP offload support. If you are planning to
run MATIP or IP Bridge support with the TPF TCP/IP native stack
support provided with APAR PJ26683, you must install the MATIP and
IP Bridge enhancements provided in APAR PJ26693. With the new PUT
11 code, you will be able to run MATIP and IP Bridge support with
either TPF offload or native stack support.
New Host Name Support
APAR PJ26161 enabled you to start a MATIP session for a
particular line number, interchange address, and terminal address
(LNIATA) as long as you associated an IP address with the LNIATA by
using the ZMATP DEFINE functional message. With MATIP
enhancements, that association no longer can be made with the
ZMATP DEFINE functional message. You must now enter a host name
with the ZMATP DEFINE functional message and use the new MATIP Host
Name user exit to associate the LNIATA with the host name. The host
name you enter with a ZMATP DEFINE functional message is saved in a
TPF collection support (TPFCS) database and is copied to the new
MATIP host name table in system heap storage whenever MATIP is
started at or above CRAS state. When your application starts a new
MATIP session with a ROUTC macro, TPF MATIP intercepts the ROUTC
macro and passes the LNIATA associated with ROUTC to the Host Name
user exit. The user exit finds the host name associated with the
LNIATA in a table you build and then searches the MATIP host name
table for the host name. Sample code is provided in the user exit
to enable you to use a hashing function to find the host name in
the MATIP host name table. The pointer to the host name entry in
the MATIP host name table is returned by the user exit to TPF
MATIP, which issues a gethostbyname() function to
resolve the host name to an IP address. TPF MATIP then uses the IP
address to issue a connect() function to the remote
host. The data passed to TPF by the ROUTC macro is sent to its
destination with the socket send() API function.
MATIP support on PUT 10 provided an application interface to
enable you to start a MATIP session for Type-A host-to-host and
Type B sessions without having to issue a ROUTC macro. That
interface required the application to provide an IP address to TPF
MATIP so that TPF could start a MATIP session with the IP address.
For PUT 11, that application interface has been replaced with a new
interface. The new interface requires the application to provide a
pointer to a host name in the RCPLORG field of a Routing Control
Parameter List (RCPL) passed to TPF MATIP when the application
enters the MATIP code directly. TPF MATIP issues a
gethostbyname() function to resolve the host name to an IP
address and uses the IP address to issue a connect()
function to the remote host. TPF saves the socket number associated
with the session in its host name table, sends the data that is
passed to it on data level D0, and returns the host ordinal number
of the host name entry to the application. When the application
sends additional data over the same session, it passes the host
ordinal in the RCPLDES field of the RCPL on subsequent enters to
TPF MATIP so that TPF can retrieve the socket from the host name
entry. TPF then issues a send() function for the data
passed on data level D0 and passes the return code from the
send() function back to the application.
IP Bridge support was not changed to include host name support,
so you must still use the ZMATP DEFINE functional message to
associate an LNIATA with an IP address when you want to start an IP
Bridge session with that LNIATA.
New ASCU Support
In the previous TPF Newsletter, I described an
agent set control unit (ASCU) as a concentrator that is associated
with a group of remote terminals. APAR PJ26161 provided the MATIP
ASCU List and the Security user exits to define tables to contain
ASCUs configured on the TPF system. With MATIP enhancements,
you can now define ASCUs through the ZMATP DEFINE functional
message and associate them with a particular TPF host name. Like
host names, ASCUs that are entered through the ZMATP DEFINE
functional message are saved in a TPFCS database and copied to
system heap storage whenever MATIP is started at or above CRAS
state.
ZMATP Functional Message Enhancements
The ZMATP ALTER functional message has been enhanced to enable
you to change host name and ASCU information that is already saved
in the TPFCS database.
ADD and DELETE options to the ZMATP functional message have been
added to enable ASCUs to be added and deleted from their associated
host name records in the TPFCS database. In addition, the ZMATP
DELETE functional message enables you to delete the entire host
name entry and its associated ASCUs from the TPFCS database.
The ZMATP DISPLAY functional message has been enhanced to
display characteristics for host names and ASCUs added to the
system through the ZMATP functional message.
The ZMATP START functional message has been enhanced to enable
you to start MATIP by host name. If you start MATIP by host name,
the host name you enter is copied from the TPFCS database to the
MATIP host name table located in system heap storage. When would
you use it? If MATIP is already running at or above CRAS state and
you add a new host name to the TPFCS database with the ZMATP DEFINE
functional message, use this enhancement to ZMATP START to start a
session with the new host name without having to stop MATIP.
The ZMATP STOP functional message has been enhanced to enable
you to stop MATIP by host name. If you stop MATIP by host name,
message traffic will no longer flow through that host name, but
MATIP will keep on running to host names that have been started and
not yet stopped.
Support for Cisco Routers
MATIP enhancements support session open requests sent
from Cisco routers that have MATIP support installed, such as Cisco
2500 series routers.
Prerequisites
APAR PJ26693, which contains the enhancements to MATIP and IP
Bridge support, is included on PUT 11. If you do not want to
upgrade your TPF system to PUT level 11, your TPF system must be at
PUT level 9 or 10 to enable the Internet Daemon to define and start
the MATIP Type-A and Type-B servers. If you are at PUT level 9 and
you have not yet installed MATIP and IP Bridge support, you need to
install APARs PJ26161, PJ26324, and PJ26359 before you install APAR
PJ26693. If you want to use MATIP with TPF TCP/IP native stack
support and you are at PUT level 9 or 10, you need to install APAR
PJ26683 before you install APAR PJ26693.
Before you use the enhancements to MATIP and IP Bridge support,
you need to enter the ZDTCP DNS functional message to define the IP
address of the DNS server to be used to resolve host names you
enter with the ZMATP functional message. The host names to be used
to start MATIP client sessions need to be defined on that DNS
server so the TPF system can resolve the host names with the
gethostbyname() function. See your network administrator if
you need assistance defining new host names in your DNS server.
If you are planning to establish MATIP sessions with a Cisco
router, that router must have MATIP support installed.
References
The following TPF documents were changed for APAR PJ26693:
- TPF Migration Guide: Program Update Tapes,
GH31-0187
- TPF Operations, SH31-0162
- TPF System Installation Support Reference,
SH31-0149
- TPF Messages, SH31-0156.
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