Extreme Networks ExtremeWare XOS 11.3, Manual

Page: 413 / 698

Configuring EAPS Shared Ports
ExtremeWare XOS 11.3 Concepts Guide
413
Figure 25: EAPS domain common link failure
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
show eaps shared-port {<port>} {detail}
command
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}
EW_102b
S4
S5
S3
EAPS1
Partner
S9
S11
S10
S1
S2
EAPS2
EAPS3
Controller
S6
S8
S7
Master
Master
Master
P1
P2
P3
P4
x
Active-Open