Specifications

242 Implementing IBM System Networking 10Gb Ethernet Switches
򐂰 Port flood blocking
򐂰 Protocol-based VLANs
򐂰 RIP
򐂰 Router IDs
򐂰 Route maps
򐂰 sFlow port monitoring
򐂰 Static MAC address addition
򐂰 Static multicast
򐂰 Uni-Directional Link Detection (UDLD)
򐂰 Virtual NICs
򐂰 Virtual Router Redundancy Protocol (VRRP)
6.2.4 Stack membership
A stack contains up to eight switches, interconnected by a stack trunk in a local ring topology.
With this topology, only a single stack link failure is allowed. An operational stack must
contain one Master and one or more Members, as follows:
򐂰 Master: One switch controls the operation of the stack and is called the Master. The
Master provides a single point to manage the stack. A stack must have only one Master.
The firmware image, configuration information, and runtime data are maintained by the
Master and pushed to each switch in the stack as necessary.
򐂰 Member: Member switches provide additional port capacity to the stack. Members receive
configuration changes, runtime information, and software updates from the Master.
򐂰 Backup: One member switch can be designated as a Backup to the Master. The Backup
takes over control of the stack if the Master fails. Configuration information and runtime
data are synchronized with the Master.
The Master switch
An operational stack can have only one active Master at any time. In a normal stack
configuration, one switch is configured as a Master and all the other switches are configured
as Members.
When adding new switches to an existing stack, the administrator should configure each new
switch for its intended role as a Master (only when replacing a previous Master) or as a
Member. All stack configuration procedures in this chapter show correct role specification.
However, although uncommon, there are scenarios in which a stack may temporarily have
more than one Master switch. Should this situation occur, one Master switch is automatically
chosen as the active Master for the entire stack. The selection process is designed to
promote stable, predictable stack operation and minimize stack reboots and
other disruptions.
Splitting and merging one stack
Members that have access to a Master or Backup (or both), despite other link or Member
failures, continue to operate as part of their active stack.
Important: In stacking mode, switch menus and commands for unsupported features
might be unavailable, or might have no effect on switch operation.
Important: If stack links or Member switches fail, any Members that cannot access either
the Master or Backup are considered isolated and do not process network traffic.