Visara FEP-4600 Planning Guide - Manual (Page 67)

37x5 to FEP-4600 Migration and Planning Guide
707117-003 6-11
Explicit Route Number and Virtual Route Numbers
Explicit Route (ER) number assignments are associated with a physical link and are a
connection between adjacent subareas. Virtual Route (VR) number assignments are from
the source subarea to the destination subarea and must be made to match in the local
VTAM gen to the remote NCP (or remote VTAM) gen. The implementation that the
FEP-4600 uses passes VR information through from one side to the other, and it is
therefore important that the VR information lines up properly. When NCP was in place
the VRs were typically from the local NCP to the remote NCP. With the FEP-4600 in
place the VRs are between the local VTAM and the remote NCP.
Since new definitions have to be created typically for the local (ESCON or FICON)
interface to the FEP-4600, it makes sense to create definitions in the local PATH table to
match what is already defined in the remote NCP’s PATH table. This information is
typically already defined in the local NCP’s PATH table that the FEP-4600 is replacing.
So if the local NCP has been using VR0 and VR1 to communicate to the remote NCP,
then when you create the local VTAM PATH definition to be used with the FEP-4600
you should also specify VR0 and VR1 so that there is not a VR mismatch.