Visara FEP-4600 Planning Guide - Manual (Page 20)

Chapter 2. Support of PU 2.0 Platforms
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Option 1 Considerations
This option is only available on older platforms that used the Luminex ESCON interface
card, and is not available on current platforms using the BARR ESCON interface card or
over FICON. When defining a Local Major Node definition for the FEP-4600, the
downstream PUs appear to VTAM as if they were physically attached to the ESCON
interface. This option is available if the PU is to be attached to the FEP-4600 via an
SDLC, Token Ring, or Ethernet (LLC) link. Defining Local Major Node PU 2.0
definitions requires one subchannel per PU.
Option 2 Considerations
This option is the preferred method of connecting PU2.0’s to VTAM, and does not have
any ESCON or FICON restriction. For this option, PUs are defined to VTAM using
Switched Major Node definitions. One or more XCA definitions are used to provide a
path between a LAN interface and the ESCON/FICON channel. SDLC defined PUs pass
through a gateway between a virtual LAN interface and the SDLC interface.
PUs currently attached to the 3745 via Token Ring use Switched Major Node definitions.
In this case the PUs should already be defined to VTAM, and no change in these
definitions should be required. The FEP-4600 will require a minimum of one XCA
definition in VTAM for each network adapter to support up to 255 concurrent DSPUs
(which makes use of only one subchannel as compared to the one subchannel per PU
described in option 1). Using the Switched Major Node definitions additionally allows
for redundant paths to be used to gain access to the host definition through multiple FEP-
4600 platforms (and through multiple channel interfaces). This is because the Switched
Major Node definition is not tied to a specific channel address.