Cisco 7513 Series, Hardware Installation And Maintenance Manual

Page: 27 / 289

Physical Description
Spares and
Field-Replaceable
Units
The
primary
spares
in
the Cisco
7513
are the
blower module and
at least
one
power
supply
Figure
1-1
shows
the
power supplies
and blower module
in
their
normal
operating positions
The
power supplies
operate
on
AC
input power
or
DC
input
power
for the
DC-input power
supplies
and
provide
DC
voltages
to
the system
components
The blower
in
the
blower module
moves
cooling
air
through
the chassis
interior from
the
bottom
of
the card
cage
to
the
top
to
prevent
internal
components
from
overheating
The
card
cage
and
backplane assembly
is
field-replaceable
unit
FRU
that
includes the chassis
interface
and
the dual
arbiter
which
are attached
to
the
backplane
The
backplane distributes
power
throughout
the
system and
contains the dual
CyBus
for high-speed
information
exchange the dual
arbiter
which
controls bus
arbitration
and
the chassis interface
which
contains the environmental
monitoring
functions for the system.The
following
sections describe the major
system
components
Dual
Arbiter
The
dual
arbiter
which
arbitrates traffic
on
the dual
CyBus
and
generates
the
CyBus clocks is
printed
circuit
board
that
is
mounted
to
the front noninterface
processor
side
of the
system
backplane
The
dual
arbiter
controls
traffic
across
the
CyBuses by
prioritizing
access
requests
from
interface
processors
This
ensures
that
each
request
is
processed
and
prevents
any
interface
processor
from
jeopardizing
the
CyBuses
and
interfering
with the
ability
of the other interface
processors
to
access
the
RSP2
The
dual
arbiter
provides
the following services
for
the
system
Clock
generationGenerates
the
Cybus
clock
and
provides private
copy
of the clock
to
the
RSP2 and
each interface
processor
CyBus
arbitrationArbitrates interface
processor requests
to
transmit
commands on
the
CyBus
The
arbitration
is
based on
round-robin
priority
scheme
to
ensure
that
all
interface
processors
have
access
to
known
portion
of the
CyBus bandwidth
Global lock arbitrationArbitrates interface
processor
and
RSP2
requests
for
the global lock
synchronization
primitive
used
to
control
RSP2
and
interface
processor
access to
shared data
structures
Note The
dual
arbiter in
the Cisco
7513
is
not interchangeable with the
arbiter
for the Cisco
7000
or the single
arbiter
for the Cisco
7505
The
dual
arbiter is
part of the card cage
assembly
and
is
not available
separately
as
spare part or
FRU
1-6 Cisco
7513 Hardware
Installation
and
Maintenance