If you are using or planning to use FICON CTC links (for VTAM) you might
want to get on the interested parties list or open your own marketing
request to IBM the same as
MR0413054727 VTAM RECOVERY OF FICON CTC LINKS
MR0130072900 VTAM RECOVERY OF FICON CTC LINKS
We converted to use FICON CTC last year and have been happy in general
but VTAM with FICON CTC does not work as well as VTAM with ESCON CTC.
At IPL you may see an error and not get cross domain links active.
IST380I ERROR FOR ID = MPLBTOHZ - REQUEST: ACTLINK, SENSE: 081C003C
IBM explained
===================================================================
If the other side of the FICON CTC is not up then VTAM is not able to
recover the link.
ESCON works differently at the hardware level. The CTC is online (after
IPL) so after VTAM activates the CTC it goes PCTD1,(and waits for the
other side to come up). For FICON the link goes NEVAC caused by a
Condition Code 3 which
indicates no path. It therefore is not waiting for the other end to come
up. The reason for the Ficon CTC devices not coming online when the 1st
partition only is IPLed is due to the concept changes. In the ESCON
environment, the customer needs to define which side will have the CTC
function. In the FICON environment the CTC control unit is not known in
advance like in ESCON and because the load of the CTC functions will be
balanced equally between each side,
it will also be necessary for the two involved channels to negotiate on
which side the CTC function will finally be.
This is why, in order to establish the negotiation, both sides must be
up, which explains why the CTCs devices are brought online when the
second partition is IPLed. The way round this is to use automation to
allow VTAM to use the FICON
CTCs when they are up. Unfortunately there is no dynamics with a CTC
short of inactivation and activation of the Major Node. I double
checked the V ACT,UPDATE=ALL command processing and function capability
beyond Switched Major nodes, Local Major Nodes and Channels defined as
APPN TRLE MPC connections. No dynamics with CTC VBUILD GROUP.
VTAM requires that at least 1 write subchannel and at least 1 read
subchannel be ONLINE to MVS when the MPC is activated
in order for the activation to work.
We've learned that FICON CTC works differently than ESCON CTC in how
they come ONLINE at power on/IPL time. A VTAM requirement has recently
(about 2 weeks ago) been opened for VTAM to wait for the FICON CTC's to
come online - and not fail the activation. For now, one of each must be
ONLINE to MVS for the activation to work.
1 read / 1 write must be ONLINE when activating VTAM MPC.
-----------------------------------------------------------------------
The 081C003C sense code indicates you do have the problem of the devices
not yet online at time of activation.
It means the channel device (CTC device) does not come up online during
MVS IPL. Vary ACT involving the device will fail with ACTLINK 081C003C.
To recover the situation, issue MVS V ONLINE command and re-issue
VTAM V NET,ACT. V NET,ACT will be required to get CTC active.
There is a Marketing Requirement in place : MR0413054727 VTAM RECOVERY
OF FICON CTC LINKS. The requirement is in the process for the release
after R8 so it will be approximately a year before it is available.
======================================================================
It continues to sound positive that this requirement will be met by IBM
in a future release after release 8. We think this is something that
must be in the next z/OS release and should be considered if at possible
to roll back to R7 and R8 as a new function APAR or APARs.
I have heard it said that IBM won't bring out any equipment which is not
as capable or more capable than it's current offering. FICON CTC was a
big step backwards for use by VTAM. We have had to put in Netview
CLISTs to deal with this manually as a customer when it should be
handled automagically by VTAM.
Just be aware of this if you are considering to use FICON CTC and
perhaps take time to contact IBM and get on the interested parties list.
If there is any chance to see this function pushed back to current z/OS
releases it seems that IBM is going to have to get a lot of interested
parties.
Best Regards,
Sam Knutson, GEICO
Performance and Availability Management
mailto:[EMAIL PROTECTED]
(office) 301.986.3574
"Think big, act bold, start simple, grow fast..."
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