Replacing existing 2074 controllers, Replacing bus and tag controllers, Determining the need for escon directors – Visara SCON-20L Installation User Manual
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SCON-20L/22L/25L/28L/3074 Planning and Installation Guide
Replacing Existing 2074 Controllers
Depending on the model, your existing 2074s support 32, 64, or 96 TN3270 clients. The
SCON-3074 supports as many as 256 sessions (128 per ESCON interface). With session
sharing, as many as 512 TN3270 clients can share those 128 sessions. Gen changes
need only be made if you need to increase the number of sessions supported or to
consolidate two or more existing 2074s.
Replacing Bus and Tag Controllers
Bus and Tag definitions and ESCON definitions are different, so you will always require
Gen changes when replacing Bus and Tag controllers with a SCON.
Determining the Need for ESCON Directors
If you have more than two mainframe platforms or have multiple LPARs on a single
mainframe that does not support EMIF, you will probably be best served by using ESCON
directors. ESCON Directors allow multiple LPARs and multiple mainframes to
communicate to a SCON through a single ESCON interface. If ESCON Directors are to
be used, consider implementing a redundant ESCON Director to eliminate a single
point of failure.
When to Use EMIF
If your mainframe supports EMIF (Enterprise Multiple Imaging Facility) and you are
running multiple LPARs, making use of EMIF can greatly reduce the number of ESCON
interfaces that are required, and fewer SCONs as well.
StorageTek LMUs Planning
StorageTek LMUs have a requirement to use a single coax connection for each LPAR
that you wish to connect the LMU to. Be sure to allow for that in your calculation for the
number of coax connections that must be provided by the SCON-2XL.
FICON Usage
The SCON does not have the ability to connect directly to FICON. You may connect
indirectly to FICON through a switch which provides the SCON with an ESCON
connection.
IBM 3290 Plasma Display Planning
The 3290 plasma display can support up to 4 sessions through a single coax connection,
but it is limited to communication to only one LPAR. Visara provides the special 3290
DSL files required and requested by the 3290 at 3290 boot time. An alternative to the