Stack Cabling - Alcatel-Lucent OmniSwitch 6850 Series Hardware User's Manual

Stack Cabling

Stack Cabling
Switches in a stack are connected to each other by stacking cables. The valid cable lengths are 1.5m (4.9
feet), 60cm (23.6 inches), and 30cm (11.8 inches). These stacking cables provide high-speed, dual-redun-
dant links between switches in a stack.
Stacking cables for OmniSwitch 6850 Series switches can be connected in any pattern. In other words, the
cable connected to stacking port A of one switch can be connected to either stacking port A or stacking
port B of the adjacent switch. However, it is strongly recommended that the cabling pattern remains
consistent across the stack. In addition, for a stack to have effective redundancy, a redundant stacking
cable must be installed between the upper-most and bottom-most switch at all times. This provides effec-
tive failover in the event of a stacking link or module failure within the stack.
The diagram below shows two recommended stacking cable patterns. For detailed information on assem-
bling a stack and connecting the cables, refer to
ware Components."
Note. When planning the stack cabling configuration, keep in mind that the switch connected to stacking
port A of the primary switch will be assigned the secondary management role by default.
Examples of Stacking Cable Patterns (Chassis Rear Panels Shown)
page 4-16
Chapter 2, "OmniSwitch 6850 Series Chassis and Hard-
A B
A B
OmniSwitch 6850 Series Hardware Users Guide
Managing OmniSwitch 6850 Series Stacks
A stack of eight switches in a crossed (stacking port
A to stacking port B) configuration. Note that a
redundant stacking cable connection exists between
the top and bottom switches. This connection is
required for effective redundancy across the stack.
A stack of eight switches in a straight (stacking port A
to stacking port A; stacking port B to stacking port B)
configuration. Note that a redundant stacking cable
connection exists between the top and bottom
switches. Again, this connection is required for
effective redundancy across the stack.
August 2007