3Com 3C16685 User Manual - Management Resilience
18
C
HAPTER
1: O
VERVIEW
AND
I
NSTALLATION
OF
THE
M
ANAGEMENT
M
ODULE
How the Management Module Can Be Used
The management module can be fitted into either of the transceiver
module slots in the Dual Speed Hub 500; refer to
“Installing the
Management Module”
on
page 20
for information on how to do
this.
When multiple Dual Speed Hub 500 units are connected together
with cascade cables, they form a single hub (called a stack). The
management module can be fitted into any one of the units and
provides management for the whole stack.
Management Resilience
Protection Against Unit Failure
The cascade cables that carry the network and management
communication between the units in the stack, have resilience built
into them which protects the communication channel should a unit
fail. You can further this resilience by using Hot Swap Cascade Units,
which allow you to remove and replace units in the stack, without
affecting the other units in the stack.
For more information about Hot Swap Cascade Units, contact your
supplier.
Protection Against Losing Management
If the stack splits in two (if one of the cascade cables becomes
disconnected), one half of the stack will lose connection to the
management module if there is just one management module in the
stack. You can protect against this by having multiple management
modules in the same stack (for example one in the top unit and one
in the bottom unit). Then, if the stack does split, both halves can be
managed because they both have access to a management module.