Bay Networks BayStack 281 Series Manual page 54

Planning a Switched Network
2-22
In Figure 2-9, three BayStack 28115/ADV switches are connected by trunk
links to form one switch community. The additional trunk link between
switches A and C ensures that the switches remain in a single community if the
trunk link between switches B and C fails. Switch ports 1 through 3 and 5
through 7 are configured to operate in feeder mode and are all part of the same
virtual LAN. Of the ports that are connected to the same Ethernet segment, one
port is designated an active feeder port and additional ports are designated
standby feeder ports.
For example switch A, switch B, and switch C are connected to Ethernet
segment 3 of an Ethernet hub through port 1 connections. Port 1 on switch A is
designated the active feeder port (switch A has a lower MAC address), while
port 1 of switch B and port 1 on switch C are designated standby feeder ports
(switch B has a higher MAC address).
If any active feeder ports or active feeder links on switch A fails, the standby
feeder port on switch B is enabled and resumes communications between the
switch and the active devices on the connected Ethernet segment until the
partitioned port reestablishes connection.
Figure 2-10 shows redundant connections between switches in different switch
communities to two Ethernet segments. This configuration provides
community-level and port-level redundancy between the devices connected to
two different Ethernet segments.
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