User guide

20 User Guide
Single Strand Fiber Failover Protection
To ensure network resiliency in the event a single strand of fiber cable breaks or
fails, the R752-1S and R752-SS (Rev B or higher) provide failover protection by
automatically forcing both ports to switch from Primary to Secondary. This
maintains the continuous flow of data in both directions.
Scenario
The diagram below shows two R752 redundant interface line cards connected
together at the Primary and Secondary ports. All ports have good link status, and
both cards are operating in full-duplex mode with the Primary ports active.
LK
AT
LK
AT
LK
AT
S
E
C
P
R
I
M
A
I
N
S
E
C
P
R
I
R752
R752
M
A
I
N
LK
AT
LK
AT
LK
AT
Line Card A
Line Card B
= LED on
= LED off
Problem
The fiber strand carrying data from Line Card B to A breaks, thus stopping the
flow of data from B to A.
LK
AT
LK
AT
LK
AT
S
E
C
P
R
I
M
A
I
N
S
E
C
P
R
I
R752
R752
M
A
I
N
LK
AT
LK
AT
LK
AT
Line Card A
Line Card B