IBM 990 - Manual (Page 250)

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zSeries 990 Technical Guide
z990 Hardware Management Console
A local Hardware Management Console must be connected to its Support Elements using
Local Area Network (LAN) wiring. zSeries 990 provide both token ring and Ethernet options
for the LAN wiring between the Hardware Management Console and the Support Elements.
The necessary LAN adapters for the Support Elements and the Hardware Management
Console may be specified as features on the system order.
Each Support Element has two LAN adapter options. Neither is the default; one of the
following must be selected:
Dual Ethernet SE
Token ring/Ethernet SE
The Hardware Management Console has two LAN adapter options. Neither is the default; you
must select one of the following:
Dual Ethernet HMC
Token ring/Ethernet HMC (traditional)
Notes on wiring with multiple adapters
It is intended that a Hardware Management Console and the SE together be connected by
only
one LAN.
Multiple adapters in a Hardware Management Console allow that Hardware Management
Console to connect with two
independent sets of SEs: one set on a token ring and a
second set on an Ethernet.
This is done to allow for migration from token ring environments to Ethernet environments.
Multiple adapters in a ThinkPad® SE are intended to allow two different Hardware
Management Consoles to have independent paths to the SE.
This is done so that the console can be controlled if one LAN goes down.
In the following sections, we describe the four wiring scenarios.
Token ring only wiring scenario
The token ring only wiring scenario, shown in Figure A-3 on page 239, is the standard wiring
approach used in previous generations of the IBM Enterprise Server Hardware Management
Console and Support Element wiring. As in previous systems, each system includes a
Multistation Access Unit (MAU) that may be used to interconnect the token ring adapter wiring
of the Support Elements to the Hardware Management Console. Token ring wiring may be
used to interconnect the MAUs to form a larger private LAN where multiple systems are to be
controlled by a single Hardware Management Console.
Important: The z890 and z990 will be the last zSeries servers to offer Token Ring adapter
features on the Hardware Management Consoles (HMCs), Support Element (SEs), and
Trusted Key Entry (TKE) workstations. The IBM 2074 Model 3 Console Support Controller
will be the last controller to offer Token Ring adapter features.
IBM
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zSeries team is making these statements to allow enterprises sufficient
opportunity to prepare for a migration to Ethernet environments.