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Stack Cabling Managing OmniSwitch 6350 Stacks
Stack Cabling
Switches in a stack are connected to each other by stacking cables. These stacking cables provide highspeed, dual-redundant links between switches in a stack.
Stacking cables for OmniSwitch 6350 switches must be connected in an A-B pattern. In other words, the cable connected to stacking port A of one switch must be connected to stacking port B of the adjacent switch. 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 effective failover in the event of a stacking link or module failure within the stack.
The diagram below shows the required stacking cable pattern. For detailed information on assembling a
stack and connecting the cables, refer to Chapter 3, “OmniSwitch 6350 Chassis and Hardware
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.
A B
A stack of four 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.
Example of Stacking Cable Pattern (Chassis Rear Panels Shown) page 7-16 OmniSwitch 6450 Hardware Users Guide October 2016
Managing OmniSwitch 6350 Stacks Stack Cabling
Redundant Stacking Cable Connection
OmniSwitch 6350 switches allow redundant stacking cable connections between the top-most and bottommost switches in a stack.
Note. For a stacked configuration to have effective redundancy, a redundant stacking cable must be installed between the upper-most and bottom-most switch in the chassis at all times.
The figure below shows how the redundant connection between the top and bottom switches in the stack ensures that data will continue to flow throughout the stack, even in the event of a connection failure at one of the stacking cables.
Stacking Cables Chassis Front
Slot 1
Slot 2
Slot 3
Slot 4
1
Data enters slot 1 via an Ethernet port. The data is passed to slot 2 over the stacking cable connection, then exits slot 2 via one of its Ethernet ports.
2 The stacking connection between slots 1 and 2 goes down unexpectedly. Data can no longer travel directly between slot 1 and 2.
Slot 1
Slot 2
Slot 3
Slot 4
However, because there is a redundant connection (the cable between slot 1 and slot 4), data is immediately passed to slot 4, then quickly traverses slot 3 and exits slot 2 to its destination.
Stacking Cable Redundancy: Recovery Following a Stacking Link Failure
OmniSwitch 6450 Hardware Users Guide October 2016 page 7-17
Stack Cabling Managing OmniSwitch 6350 Stacks
Redundant stacking cables provide a form of dual redundancy. As shown in the figure above, the redundant cable allows traffic to flow in the event of a stacking link failure. The redundant cable also provides failover if a switch goes down within the stack. Traffic continues to flow between the modules that remain operational, as shown in the diagram below:
Stacking Cables Chassis Front
Slot 1
Slot 2
Slot 3
Slot 4
1
Data enters slot 1 through an Ethernet port. The data traverses slot 2 via the stacking cables and exits slot 3 through one of its Ethernet ports.
2
The slot 2 switch goes down unexpectedly.
Data can no longer move through slot 2.
Slot 1
Slot 2
Slot 3
Slot 4
However, because there is a redundant connection (the cable between slot 1 and slot 4), data immediately traverses slot 4 and then exits slot 3 to its destination.
Stacking Cable Redundancy: Recovery Following a Switch Failure within the Stack
Checking Redundant Stacking Cable Status
To check whether a redundant stacking cable connection exists between the top-most and bottom-most switches in the stack, use the show stack status command. For example:
Redundant cable status : present
Tokens used : 1
Tokens available : 31
In this example, a redundant stacking cable connection is present between the top-most and bottom-most switches in the stack.
page 7-18 OmniSwitch 6450 Hardware Users Guide October 2016
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