From: [email-masked] (Dave Mayhew)
Date: Tue, 23 Jan 1996 22:59:43 -0500

Royal Bank would like to raise its concern over the lack of XRF support in
DLUR. IBM indicates that MNPS will replace XRF, however as we understand
current MNPS, a number of shortcomings will prevent us from replacing XRF
with MNPS and moving to APPN.      

1. Typically we would have IMS running on multiple systems, using    Generic
resource to balance the LU sessions across these systems.
   If one of the IMS's fails, VTAM/MNPS will hold the sessions until that
   same IMS is recovered on that system. (this is quite different than
XRF today, as these sessions would be switched to the alternate IMS
   without distruption (class 1). 
   MNPS does not provide any capability to 'switch' sessions to an 
   alternate (ie: no method for instance, to increase availability or 
   reduce the impact of planned outages).        
   
2. If the entire Image fails (VTAM/MVS), the same distrupted IMS needs to be
restarted on another image! (ie: same APPL/ACB). These sessions again
   should be 'switched' or moved to an alternate IMS running a separate
   APPL non-distruptively. I guess we fail to see the Multi in MNPS. 

3. We had understood that Uservar and Generic resource were mutually 
   exclusive. We now understand that we could use Generic Resource with 
   Uservar, however an LU affinity gets assigned at session setup and 
   is tied to particular system. If IMS fails, and switch could ocurr, there
is no way to break this affinity (ie: POA or command). 

The bottom line is that MPNS may not allow us to eliminate the XRF 
capability provided by NCP. This is an issue in migrating to APPN without
any XRF support in DLUR. There may not be many XRF users in the world (is
that why XRF support is not in DLUR?), however these are usually large IBM
shops which are considering the move to APPN...

thx, dave                                                                

 
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