Allied Telesis AlliedWare Plus Operating System Version 5.4.4C (x310-26FT,x310-26FP,x310-50FT,x310-50FP) User Manual
Page 1501
EPSR Introduction and Configuration
Software Reference for x310 Series Switches
C613-50046-01 REV A
AlliedWare Plus
TM
Operating System - Version 5.4.4C
57.19
■
A transit node that is connected to a shared link will change its behavior in the
following ways:
«
It will compare its priority settings applied to each of the instances sharing the
common link. So for the network of
Transit Node D
will compare the priority setting for Ring One, with the priority setting for Ring
Two.
If the shared link fails, the transit node will only issue a Transit Node Links Down
message on the ring that is configured with the highest priority.
The result of these behavior changes is that when the shared link fails, only the master
node located on the higher priority ring will unblock its secondary port; because this is the
only master node that will receive the Transit Node Links Down message. Note also that
the master node will receive these messages from the transit nodes at either end of the
broken shared link (Nodes D and E). This concept is illustrated in
Figure 57-12: EPSR behavior under fault conditions with Superloop enabled
For this process to work requires certain configuration rules to be obeyed.
Links
Down
Message
- Only sent to high priority m
aster
Ring
Dow
n Flush
Message - Only sent from high priority m
aster
Healt
hcheck
Messages - Timeout Exceeded
O
pt
io
na
l
Priority 60
Priority 120
Optional
Optional
O
pt
io
na
l
H
ealth
che
ck
M
es
sa
g
e
s -
T
im
eo
ut
Primary
Port
Secondary
Port
Master
Node-L1
Port
Unblocks
Master
Node-L2
Primary
Port
Secondary
Port
Remains
Blocked
EPSR_SLoop-Priority_Set.eps
Transit
Node D
Transit
Node E
Common
Segment
(broken)