Cisco 7000 Series Hardware Installation And Maintenance page 74

Station
wrap
Ring
212 DAS
Failure
Station
Figure
could
failure
second cause
would the ring
into
segment
in
example Station
Figure
if
communication
no for
because
path
segmentation
avoid
switches
bypass
Optical
normal
an
operation
optical
When
station
uninterrupted
reaches
onto the ring before
it
shows
2-13 an
Figure optical
the Station
on
is functioning
left
switch allows the
essentially
switch
the
fails
bypass
optical
The
switch reroutes
bypass
back
and sends out the ring
to
it
back on
without
itself
wrapping
when back
out
to
it
sending
allow the
to pass through
signal
just
on
next
the station
neighbor
Station
Station
and
Recovery
Ring
Example
the ring both directions
to in
wrap
two
could
rings that
separate
2-12 Station
fails after
fails
them
between
exists
by eliminating
segmentation
switch allows
the
light
bypass
with switch
bypass fails
the station so the ring does
failed
switch Station
installed at
bypass
so the
normally
optical
without
it
to pass through
signals
enables
the
bypassed configuration
by
the signal intercepting
light
This allows
the
to
signal
However stations that
switches
the ring Optical bypass
them
so
significant
the ring is far away
Preparing
Station
station
from the point of failure
communicate
with each
not
and each
will
Stations
failures cause
Subsequent
from
the ring
failed stations
signal to through
directly
pass
the bypass switch reroutes the
back on
have
not
to
wrap
normal
In
the
configuration
switch
transparent
bypass appears
However
interruption
shown
on the
right
before reaches failed
the
it it
maintain
existing path
its
repeat the signal
normally
are
operating
the
do not repeat or drive
when
occur the
loss
can
signal
Preparing
Network Connections
-Ring
wrap
which
For
other
be
isolated
additional
During
itself
back
signal
itself
shown
The
Station
if
2-13
in
Figure
Station
and
direction
they
signal
downstream
223
for Installation