Visara FEP-4600 Planning Guide - Manual (Page 81)

37x5 to FEP-4600 Migration and Planning Guide
707117-003 7-1
Chapter 7. NULL SNI Network
To replace a 37x5 that is currently implemented as a Gateway NCP and providing a Null
Network connection to another network, the FEP-4600 must handle the null network role
of the Gateway NCP. The diagrams below illustrate how the FEP-4600 replaces the 3745.
In the ‘Before’ diagram, there are two networks (NET1 and NET2), each with a Gateway
VTAM and a Gateway NCP. The two NCPs provide a Null SNI network (NULL); in this
case through a Token Ring connection. Note that the Null SNI network connection could
also be over SDLC, routed LLC over Frame Relay, or a routed DLSw connection.
The ‘After’ diagram shows the FEP-4600 ESCON attached through a Channel to Channel
connection to the local host, and Token Ring attached to the remote 3745. Remember, the
type of connection to the remote network (Token Ring, Ethernet, SDLC, Frame Relay, or
routed DLSw) appears the same to the adjacent VTAMs. Although the subarea
previously used by the 3745 (SA04) could have been used by the FEP-4600, it is usually
better to assign a new subarea so that testing can more easily be done prior to the final
replacement of the 3745.
PROD1
VTAM
SA01
PROD2
VTAM
SA02
PROD3
Gateway
VTAM
SA03
CPU 3745 3745 CPU
ACME1
Gateway
VTAM
SA10
GWNCP4
Gateway
NCP
GWNCP14
Gateway
NCP
NET1
SA04 NULL
SA98
Null Network
NULL
SA99 NET1
SA14
NETID=NULL
Before
TGN=1
TGN=3
TGN=1
PROD1
VTAM
SA01
PROD2
VTAM
SA02
PROD3
Gateway
VTAM
SA03
After
CPU FEP-4600
CTC
3745 CPU
ACME1
Gateway
VTAM
SA10
CTC
Null Network
NETID=NULL
NETID=NET1
NETID=NET2
NET1 - SA05
FEP4600
NULL - SA98
GWNCP14
Gateway
NCP
NULL
SA99 NET1
SA14 TGN=1
TGN=2
TGN=3