Extreme Networks ExtremeWare XOS 11.1, Manual

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Configuring EAPS Shared Ports
ExtremeWare XOS 11.1 Concepts Guide
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If the common link fails, both the controller and partner go into a “blocking” state. The partner never
actually does any blocking. Only the controller is responsible for blocking to prevent a superloop while
at the same time maintaining connectivity. When the common link fails, the controller keeps one of its
ports in the forwarding state and marks it as “Active-Open,” and the remaining ports are marked as
“blocked.” There can be only one “Active-Open” port, and that port must be on a segment that is “Up.”
When the common link comes back up again, the controller goes from a “blocking” state to a
”Preforwarding” state; it keeps the ports temporarily blocked to prevent a temporary loop.
Steady State
In steady state when the common link is up, both the controller and partner are said to be in the
“ready” state. After EAPS has converged and the EAPS master node has blocked its own secondary
ports, the controller puts all its ports into “forwarding,” and goes back to “ready” state.
Figure 19: Multiple EAPS domain steady state
Figure 19 shows a multiple EAPS domain steady state, where:
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EAPS1 is the EAPS domain for ring S1, S3, S4, S5, and S2
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EAPS2 is the EAPS domain for ring S1, S6, S7, S8, and S2
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EAPS3 is the EAPS domain for ring S1, S9, S10, S11, and S2
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P1, P2, P3, and P4 are the ports on switch S1
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P5, P6, P7, and P8 are the ports on switch S2
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S5, S8, and S11 are the master nodes of their respective EAPS domains
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S3, S4, S6, S7, S9, and S10 are the transit nodes of their respective EAPS domains
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S1 and S2 are running EAPSv2
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S1 is the controller
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S2 is the partner
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P1 is the EAPS shared port on switch S1
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P5 is the EAPS shared port on switch S2
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Link ID 10 is the unique identifier for the common link
EX_104
S4
S5
S3
EAPS1
Partner
S9
S11
S10
S1
S2
EAPS2
EAPS3
Controller
S6
S8
S7
Master
Master
Master
P1
P5
P6
P7
P8
P2
P3
P4
Common
link
link ID=10