John

I'm glad you've got over the problem.

> It might be best if each specific problem is presented, sense codes and all.

is what I said last time.

I am very well aware of the problem which is solved by specifying a value for 
the APPNCOS start option. Why? Because I had to solve the identical problem 
myself a few months ago - actually - and you may find some encouragement 
in this - the *only* problem that I had to solve in the migration. 
Incidentally, 
the product just happened to be NetView FTP trying to set up a session with 
another NetView FTP with the problem showing itself when there was an 
attempt to set up a file transfer.

The reason you - for now - solved your problem by specifying the APPNCOS 
start option is that you - or some predecessor - had a "rush of blood" perhaps 
long ago and actually set up a private mode table entry with a subarea COS 
name - having first, of course, set up a subarea COS table and stored it in 
VTAMLIB. If one's assessment of a customer site is that they are unlikely to 
have been sufficiently adventurous to establish COS entries - as it was in my 
case having seen some private mode table entries which lacked COS 
operands - it doesn't seem necessary to worry about the APPNCOS start 
option.

Another excuse not to have changed the APPNCOS start option value from 
NONE, the default, to something like #CONNECT, is to leave a trap for just the 
problem about which we would have read had you actually described your 
problem in detail. Having detected such a problem the change to the private 
mode table entry could then be made in order to ensure that an APPNCOS 
operand was added which had the same significance as the existing subarea 
COS operand.

I could guess that the subarea COS operand that caused your problem 
mapped to a virtual route number which you - or your predecessor - intended 
always to be used for interactive traffic - I'm relying here on the fact that 
the 
application was Supersession - and also to a transmission priority of 2, the 
highest of the subarea transmission priorities.

All that being so, I would advise that you locate the offending private mode 
table entry in the source of the private mode table - wherever it is! - add an 
appropriate APPNCOS operand such as #INTER, assemble and linkage edit the 
table overriding the existing mode table in your VTAMLIB. You can then reset 
the APPNCOS start option to NONE ready for the next similar problem - with 
which you now know how to deal.

Let's see if I can reconstruct the problem you were having - and what you 
should have presented as your problem.

If I remember correctly, we first had to track down a log of the VTAM where 
the problem in the NetView FTP was manifest and check messages at the 
appropriate time. There was one of those message sequences where the 
SSCPs tried in the subarea serial search are listed with the sense code 
returned from each. One of the SSCPs, a pseudo-SSCP, was ISTAPNCP which 
indicates the point at which the search entered the APPN part of the network 
at that particular VTAM node. The sense code returned was 80140002, 
essentially, "APPN COS not found". This was caused because there was a(n 
unexpected) subarea COS specified as COS=WHATEVER on the MODEENT 
macro for the mode table entry used by NetView FTP. Since there was no 
APPNCOS operand specified on the MODEENT macro for this mode table entry, 
VTAM obliges itself to assume that the name to use for the APPNCOS operand 
is the same as the name used for the COS operand.[1]

Since there is no APPN COS table entry WHATEVER, VTAM is about to give up 
when it remembers there is one last chance, namely the name specified in the 
APPNCOS start option put there as what in English schoolboy cricket is 
the "long stop" fielding position for when the wicket keeper makes a mess of 
things - he might be excused as a very fine "third man" if the title "long 
stop" 
was considered too undignified!

Seriously, the APPNCOS start option is obviously a very crude tool to employ 
in order to select a route and set transmission priority since there is no 
distinction between different types of session with different requirements. I 
have already indicated that you probably would want to use #INTER for 
sessions involving Supersession. If you also had had the same problem that I 
did with NetView FTP, I would then have advised you to specify #BATCH as 
the value of the APPNCOS operand - horses for courses - what's sauce for the 
goose is not necessarily sauce for the gander ...

Checking now with the description of the APPNCOS start option, I see that 
the manual authors also warn against relying on this start option:

<quote>

If a requested Class of Service cannot be found, the value you specify in 
APPNCOS is substituted for it, and there is a possibility that the 
characteristics of the substitute Class of Service are not the ones you 
intended for the route.

For example, a secure Class of Service might have been intended, but the 
substitution provided in APPNCOS might offer a Class of Service that uses 
unsecured links.

</quote>

The example I would have used would be the following:

For example, a secure high transmission priority might have been intended, but 
the substitution provided in APPNCOS might offer a low transmission priority so 
that the performance of interactive traffic is destroyed by batch traffic.

Thanks anyhow for letting us know  - in a roundabout way - what your 
problem was and that it can now be solved. That so infrequently happens with 
the problems with which I try to assist.

Chris Mason

[1] Extracted from the Communications Server SNA Network Implementation 
Guide > Chapter 13. Network routing > Network routing and resource location 
for APPN nodes > APPN Class of Service > What is the APPN Class of Service 
default in a user-coded logon mode table?

<quote>

If the APPNCOS operand is not coded on the MODEENT macroinstruction, 
VTAM checks the COS operand value.

- If the COS operand value is coded, VTAM checks for an APPNCOS definition 
by the same name as the COS name. If VTAM does not find an APPNCOS 
definition by the same name as the COS, it fails the session request, unless 
the APPNCOS start option is defined with a substitute APPN Class of Service 
name.

- If the COS operand is not coded, VTAM defaults APPNCOS to #CONNECT, 
regardless of the setting for the APPNCOS start option.

</quote>

On Tue, 9 Jun 2009 11:56:11 -0500, John Au <[email protected]> wrote:

>PAT,
>
>We included a default COS definition in our startup options
>(APPNCOS=#CONNECT) and now everything is working great!  The information
>you provided was very helpful.  Thanks a million.
>
>Regards,
>
>John Au

----------------------------------------------------------------------
For IBM-MAIN subscribe / signoff / archive access instructions,
send email to [email protected] with the message: GET IBM-MAIN INFO
Search the archives at http://bama.ua.edu/archives/ibm-main.html

Reply via email to