Extreme Networks ExtremeWare XOS Guide Manual page 413

Figure 25: EAPS domain common link failure
S3
S4
EAPS1
S5
Master
When the common link is restored, the controller goes into Preforwarding state. After the controller
receives notification from the master nodes that they have converged and blocked their secondary ports,
the controller opens all ports.
If you have an EAPS configuration with multiple common links and a second common link fails, the
controllers continue to take steps to prevent a superloop. In addition to having one controller with an
"Active-Open" port, the controller with the smallest link ID becomes the "root blocker." There can be
only one "root blocker" in the network.
Port Considerations
In an EAPS shared port configuration, the segment ports are sorted in ascending order based on their
port number, not the order you add an EAPS domain to EAPS shared ports. This is particularly useful
when planning your EAPS configuration.
The benefit of sorting ports in ascending order is evident if a common link fails. The port with the
lowest port number among the segment ports in the "UP" state becomes the "Active Open" port. When
configuring your EAPS domain, keep the port numbers in mind. For high bandwidth links, utilize
lower port numbers, and for low bandwidth links, utilize higher port numbers. This way, if a common
link fails, the high bandwidth link is still available.
NOTE
The order you add EAPS domains to EAPS shared ports is relevant if the EAPS domains have matching ring ports
and participate in spatial reuse. In this case, the
displays the newly added EAPS domain after all other existing EAPS domains with the same matching ring port.
To display EAPS shared port status information, use the following command:
show eaps shared-port {<port>} {detail}
ExtremeWare XOS 11.3 Concepts Guide
P3
P2
Active-Open
S1
Controller P4
P1
x
EAPS2
S2
Partner
show eaps shared-port {<port>} {detail}
Configuring EAPS Shared Ports
S9
EAPS3
S6
S10
S7
S8
Master
S11
Master
EW_102b
command
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