EOTec 2104 User Manual
General Features and Capabilities
7
General Features and Capabilities
This section explains the primary Ethernet and fiber capabilities of the EOTec 2104
Ethernet Ring Switch.
Ring Algorithm and Performance
The Ring feature utilizes a special algorithm that assures very fast recovery times. Each
EOTec 2104 Ethernet Ring Switch utilizes the special high-speed algorithm to keep track
of the health of the ring. In a healthy ring (a complete ring), one ring switch is
automatically picked to act as a master (switch with lowest MAC address) for the ring
network. Alternatively, you can designate one of your ring switches to be the master
using the EOTec 2104 Switch Tools. It is the master switch
’
s job to determine which one
of its local ring ports are to be in the forwarding or backup state. The ring port chosen to
be in the backup state is where the backup segment of the ring will be. By default, the
ring port with the higher port number will become the backup port.
All ring switches in the ring must have a way to keep track of each other in case a failure
in communication occurs along the ring. To keep track of the health of the ring, the
EOTec 2104 Ethernet Ring Switches periodically send test messages to each other.
Therefore, the ring switches can sense if a ring gets cut at a certain location and will
take the appropriate action to bring the network back online. The ring will recover after
the last switch knows about the situation and takes appropriate action to rectify the
communication problem.
To estimate recovery time, multiply 5 mS times the number of switches, and then add
30 mS (for loss of link errors) or 60 mS (for message loss errors). For example, a ring of
10 switches would have a recovery time of 80 mS for the typical loss of link type errors.
Master Switch Selection
As mentioned above, the ring switch with the lowest MAC address automatically
becomes the master and blocks one of its ports (highest number port). Alternatively, you
can designate one of your ring switches to be the master using the EOTec 2104 Switch
Tools. There is a simple check box where you can select
Automatic
or
This Switch
for
the master ring switch selection. This advanced capability allows you to control where
the backup port will be in your network. It is recommended that only one ring switch be
designated as the master. If more than one is designated as the master, the one with the
lowest MAC address will prevail.
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