Visara FEP-4600 Planning Guide - Manual (Page 63)

37x5 to FEP-4600 Migration and Planning Guide
707117-003 6-7
PU 4 Gateway to 3745 Operation
Being a gateway implementation, the FEP-4600 spoofs both the upstream ESCON
connection and the remote 3745. The FEP-4600 does not use NCP in any form or fashion
and does not have a real PU 4 running inside of it, but it does handle the PU4 data
streams. Because NCP is no longer in the picture, there is no need to create a load module
or perform a load of NCP from VTAM.
The FEP-4600 performs its gateway function by appearing as one or more adjacent
subareas to the existing local VTAM(s). This allows you to define a pathway through the
FEP-4600 as a Channel-to-Channel connection. The FEP-4600 becomes the ‘next hop’ in
the pathway to remote VTAM (and NCP) subareas. Although it is possible to define the
FEP-4600 to use the same subarea as the 37x5 that it is replacing, it is not always the
desired method (it makes testing and partial implementation more difficult).
The number of Channel-to-Channel connections that you need to define is determined by
the number of remote NCP connections that are needed, and the number of local adjacent
VTAM links that are required. Each connection to a remote NCP requires a Channel-to-
Channel definition for the FEP-4600 for each VTAM that appears directly adjacent to the
FEP-4600, and utilizes one of the 256 subchannels supported by the FEP-4600 ESCON
interface.
Because of the nature of the CTC protocol, CHPIDs should not be shared between
LPARs for PU4 connections. When an ESCON director is used, each LPAR should have
a separate CHPID into the director. When no ESCON director is used, then each LPAR
should interface into the FEP-4600 through a separate CHPID. Note that each FEP-4600
platform supports a maximum of two ESCON and four FICON interfaces. Each Channel-
to-Channel connection represents the host side of a Transmission Group (TG).
PROD1
VTAM
SA01
PROD2
VTAM
SA02
PROD3
VTAM
SA03
CPU
Viewed from the ESCON Side
SA09
CTC
SA10
SA14
SA22
SA29
SA30
FEP-4600
CTC