User manual

62 Publication ENET-UM001I-EN-P - January 2010
Chapter 5 Configure a Supervisor on a Device-level Ring Network
Active Ring Supervisor
When multiple nodes are enabled as supervisor, the node with the numerically
highest precedence value becomes the active ring supervisor; the other nodes
automatically become back-up supervisors.
The ring supervisor provides two main functions:
• Manage traffic on the DLR network
• Collect diagnostic inform
ation for the network
Back-up Supervisor Node
At any point in time, there will only be one active supervisor on a DLR
network. However, we recommend that you can configure at least one other
supervisor-capable node to act as back-up supervisor nodes. During normal
operation, a back-up supervisor behaves like a ring node. If the active
supervisor node faults, the back-up supervisor with the next numerically
highest precedence becomes the active supervisor.
If multiple supervisors are configured with the
same precedence value (the
factory default value for all supervisor-capable devices is 0), the node with the
numerically highest MAC address becomes the active supervisor.
We recommend that you:
• configure at least one back-up supervisor.
• configure your desired active ring supervisor with a numerically higher
precedenc
e value as compared to the back-up supervisors.
• keep track of your network’s supervisor-precedence values for all
super
visor-enabled nodes.
For more information about how to configure a supervisor, see Configure
Supervisor Nodes on a DLR Network on
page 64.
IMPORTANT
While a back-up supervisor is not required on a DLR network,
we recommend that you configure at least one ring supervisors
for your ring network.