Steady State - Extreme Networks ExtremeWare XOS Guide Manual

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
S3
EAPS1
S4
S5
Master
Figure 19 shows a multiple EAPS domain steady state, where:
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
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ExtremeWare XOS 11.1 Concepts Guide
P3
P2
S1
P4
Controller
P1
Common
EAPS2
link ID=10 link
P5
S2
P8
Partner
P6
P7
Configuring EAPS Shared Ports
S9
S6
EAPS3
S10
S7
S8
Master
S11
Master
EX_104
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