Allied Telesis AT-DC2552XS, Руководство по установке, Страница: 42 / 96

Chapter 2: VCStack Overview
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Stack Formation
As previously mentioned, a VCStack always contains a stack (active)
master and a stack member (backup). To be part of a stack, a switch must
connect to the other potential stack member via dedicated stacking ports.
See Figure 16.
Figure 16. Stacking Ports
Once the switches have been physically connected, powering the
members on sets off a number of automatic processes that enable the
stack members to detect the presence of one another and form
themselves into a VCStack.
Long-Distance Stacking
You can extend the distance between stacked units up to the maximum
distance supported by the particular QSFP+ port you are using. This
capability enables you to create a stack of 2 geographically separated
switches as a single stack.
The Role of the
Stack Master
In addition to being a member of its VCStack, the stack master manages
functions such as software version control and distribution, routing
processing, and network management.
Selecting the Stack Master
The stack members are able to automatically select which switch will
become the stack master. This selection is based on two components:
1. The stack member’s priority setting.
2. The stack member’s MAC address.
For both components, the lower the number, the higher the priority will be.
To set the stack priority, run the STACK PRIORITY command. Note that
changes to these settings will not take effect until the next master re-
election. To display these components run the SHOW STACK command.