Robert
This whole discussion should really have been started in the IBMTCP-L
list[1] rather than the IBM-MAIN list. As far as the IP component of
Communications Server (CS) is concerned, in IBMTCP-L scintillate the
brightest stars.
In your original post you asked whether or not it was possible to run both
the IP component of CS and the Interlink program together. I suppose it is
possible that one or the other could take possession of a common piece of
storage that both will reference in order to prevent more than one program
to run and behave as an IP node. However since you have both running
together, that presumably does not happen.
If the interfaces controlled by one IP node connect to the same intranet as
the interfaces controlled by the other IP node - or both connect to the
Internet - then you need to control the inbound routing appropriately.
Otherwise there cannot be a problem. What the software does in the privacy
of its own address space is entirely its business and that of nobody else!
If I've missed something important here I hope to be corrected.
[1] For IBMTCP-L subscribe / signoff / archive access instructions, send
email to [EMAIL PROTECTED] with the message: INFO IBMTCP-L
-
In an earlier post which I have not retained in my inbox, you were concerned
about different interpretations of the socket API. That flavour of the
socket API used with the transport protocols which sit on top of the IP
layer is quite well-defined. In any case, what little I know/knew of
Interlink was that they set themselves up as a competitive alternative to
TCP/IP for MVS - as the IP component of CS used to be named. Thus any APIs
*ought* to be identical.
Also from an earlier post, I suppose I should be glad you happened to
mention "CINET". You have set up CINET presumably because you imagined that
you had multiple instances of the IP component of CS - which, of course, you
don't. Please reread what I just said and the following which I found as the
first hit searching the CS IP Configuration Guide:
<quote>
Common INET physical file system (CINET PFS)
If you wish to run multiple z/OS Communications Server TCP/IP stacks
concurrently, you must use the Common INET (CINET) configuration. In this
configuration, up to a maximum of eight TCP/IP stacks can be active at any
time.
</quote>
You may be sure that IBM means just the IBM-supplied software for creating
the appearance of an IP node and absolutely not software from any other Tom,
Dick or Harry!
The point is that z/OS has features which specifically allow for multiple
instances of CS IP. These show up in the BPXPRMxx member of SYS1.PARMLIB. In
place of a single set of "INET" statements such as
FILESYSTYPE TYPE(INET) ENTRYPOINT(EZBPFINI)
NETWORK DOMAINNAME(AF_INET) DOMAINNUMBER(2) MAXSOCKETS(10000)
TYPE(INET)
I expect you have something like (taken from a study I did some years back
on CINET)
FILESYSTYPE TYPE(CINET) ENTRYPOINT(BPXTCINT)
NETWORK DOMAINNAME(AF_INET)
DOMAINNUMBER(2)
INADDRANYPORT(61000)
INADDRANYCOUNT(4000)
MAXSOCKETS(64498)
TYPE(CINET)
SUBFILESYSTYPE NAME(TCPIP)
TYPE(CINET)
ENTRYPOINT(EZBPFINI)
DEFAULT
SUBFILESYSTYPE NAME(TCPIPC)
TYPE(CINET)
ENTRYPOINT(EZBPFINI)
Since I can't see the Interlink logic participating in this CINET scheme, I
can't see any role for setting up your CINET environment.
-
Now I can get to the points that arise from this post.
Assigning the same IP address to two different interfaces is possible only
when the interfaces connect to two completely independent intranets. Is that
your situation? I suspect it is not and so what you are proposing is
forbidden.
It is possible for two different LPARs to share a port on an OSA feature and
a program supporting the behaviour of an IP node running in the LPAR can
allocate the channel address representing the OSA port. However the OSA
feature logic in the shape of the OSA address table (OAT) presumes, in
effect, that the IP nodes connect to the same intranet (or the Internet) and
requires different IP addresses - for the simple reason that the routing of
an inbound IP packet to a particular LPAR depends on the destination IP
address.
This has nothing whatsoever to do with VIPAs - although you can complicate
what I have just said by adding VIPAs into the mix!
As for the "host name", again it is the view of your systems from the
outside world which matters. You can use the same "host name" only if, when
it is represented in a name server, it is qualified with a different suffix.
It is a standard feature of the name server system that a name can map to
multiple IP addresses. You need only examine the gethostbyname() socket call
which is the call most used to access the name server system I expect. Here
the returned structure is a list of IP addresses. A well-written client
socket program, having used the gethostbyname() call prior to attempting to
initiate a TCP connection, should try each of the IP addresses in the list
in turn before giving up on the connection.
Chris Mason
----- Original Message -----
From: "Johnston, Robert E" <[EMAIL PROTECTED]>
Newsgroups: bit.listserv.ibm-main
To: <IBM-MAIN@BAMA.UA.EDU>
Sent: Wednesday, August 22, 2007 9:51 PM
Subject: Re: CA to IBM TCP conversion
First off let me thank the previously un-thanked Bob and Shelia for their
responses...
I have both the CA and IBM stacks running concurrently now. They use
different OSA's, different IP addresses, and different host names. I am
pausing to apply maint to the CA stack before continuing down my path. I
still wonder about some things and would appreciate any discussion.
Can you configure 2 tcp stacks to use the same IP address and/or OSA?
All traffic comes in one way and gets sorted out from there. I read some
about VIPA but it didn't all take the first time.
Can you/should you configure one host name that has multiple IP addresses
assigned to it?
For my purposes (testing apps to convert from CA to IBM), is my system
configured ok w/ 2 IP's and host names? Or would it be better another way?
These questions may not make sense. I am having trouble understanding all
the
relationships between host name(s), IP address(es), and the rest of the IP
world.
Thanks,
Robert
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