Reference Guide

Stacking S-Series Switches | 697
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Stacking S-Series Switches
Stacking S-Series Switches is supported on platforms z.
Using the FTOS stacking feature, multiple S-Series switch units can be interconnected with stacking
interfaces. The stack becomes manageable as a single switch through the stack management unit.
This chapter contains the following sections:
• S-Series Stacking Overview
• Important Points to Remember
• S-Series Stacking Configuration Tasks
S-Series Stacking Overview
The S55 supports up to 12 stack members with FTOS version 8.3.5.1.
A stack is analogous to an E-Series or C-Series system with redundant RPMs and multiple line cards.
FTOS elects a primary and secondary management unit, and all other units are member units. The
forwarding database resides on the primary, and all other units maintain a sychnronized local copy. Each
unit in the stack makes forwarding decisions based on their local copy.
FTOS presents all of the units like line cards; for example, to access GigabitEthernet Port 1 on Stack Unit
0, enter
interface gigabitethernet 0/1 from CONFIGURATION mode.
High Availability on S-Series Stacks
S-Series stacks have primary and secondary management units analogous to Dell Networking Route
Processor Modules (Message 39-1). The management units synchronize the running configuration and
protocol states so that the system fails over in the event of a hardware or software fault on the primary. In
such an event, or when the primary is removed, the secondary unit becomes the stack manager and FTOS
elects a new secondary. FTOS resets the failed management unit, and once online, it becomes a member
unit; the remaining members remain online.