IBM RackSwitch G8000, Application Manual

Page: 150 / 362

148
RackSwitch G8000: Application Guide
Stacking Overview
A stack is a group of up to six RackSwitch G8000 switches with IBM Networking OS
that work together as a unified system. A stack has the following properties,
regardless of the number of switches included:
•
The network views the stack as a single entity.
• The stack can be accessed and managed as a whole using standard switch IP
interfaces configured with IPv4 addresses.
• Once the stacking links have been established (see the next section), the
number of ports available in a stack equals the total number of remaining ports of
all the switches that are part of the stack.
• The number of available IP interfaces, VLANs, Trunks, Trunk Links, and other
switch attributes are not aggregated among the switches in a stack. The totals for
the stack as a whole are the same as for any single switch configured in
stand-alone mode.
Stacking Requirements
Before IBM N/OS switches can form a stack, they must meet the following
requirements:
•
All switches must be the same model (RackSwitch G8000).
• Each switch must be installed with N/OS, version 6.8 or later. The same release
version is not required, as the Master switch will push a firmware image to each
differing switch which is part of the stack.
• The recommended stacking topology is a bidirectional ring (see Figure 18 on
page 154 ). To achieve this, two 10Gb Ethernet ports on each switch must be
reserved for stacking. By default, 10Gb Ethernet ports 51 and 52 (via optional
10GbE modules installed at the back of the switch) are used.
• The cables used for connecting the switches in a stack carry low-level,
inter-switch communications as well as cross-stack data traffic critical to shared
switching functions. Always maintain the stability of stack links to avoid internal
stack reconfiguration.