Magnum DS880 Dual-Speed Stackable Hubs Installation and User Guide (05/01)
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2.3
Stacking Magnum DS880s
Up to four Magnum DS880s can be stacked to operate as one 10/100 dual-speed
repeater with up to 32 dual-speed ports. Normally, one Magnum DS880-B hub per stack is
needed to provide a
switched interconnection
between the two separate
100Mb and 10Mb traffic
domains in the stack.
Additional stacked units
are normally Model
DS880-A “add-on” units,
which cost less.
OUT
IN
OUT
IN
OUT
IN
OUT
IN
FAN EXHAUST
Figure 2.3 : Magnum DS880’s stacked. Cables connect between “Out” and “In” Ports
The DS880-B models with the bridge module inside look the same as the DS880-A
units (no bridge inside) from the outside. The “BR” LED on the front will light up when power
is applied to indicate that a DS880 is a -B (bridge inside) model. (The “BR” LED will be off if
the unit is a Model DS880-A). The DS880-B models cannot be stacked together, as their
internal bridges would not be able to function properly when more than one is present. (Note
that two DS880-B units may be cascaded to operate together, however). Use DS880-B models
un-stacked, or with only 1 Model DS880-B in a DS880 stack. See Section 2.7, Example 3.
When stacking DS880’s, please make sure to use only the shielded 9-inch long
stacking cable provided with each DS880-A unit. The cable length is designed to provide
proper operation of up to four DS880 units in a stack, and longer cables or unshielded cables are
not permitted as they will not operate properly at 100Mb speeds.
The 9-inch length is enough to provide for side-by-side stacking. This can be
convenient when locating the DS880s in a rack, for example, as two DS880s will fit side-by-side
on a tray in a standard 19” rack space.
When connecting DS880s in a stack, use the stacking cable to connect the “Out”
stacking port from one DS880 unit to the “In” stacking port of the other. Push in the cable
connectors until they snap in firmly. Also, leave space in the left-rear area for the exhaust of the
internal cooling fan in each DS880 unit. See Figure 2.3 above.
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