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priority.
In
this
case,
critical
service
packets
are
sent
preferentially
and
non
‐
critical
service
packets
are
sent
when
critical
service
groups
are
not
sent.
The
disadvantage
of
SP
queue
is
that:
if
there
are
packets
in
the
queues
with
higher
priority
for
a
long
time
in
congestion,
the
packets
in
the
queues
with
lower
priority
will
be
“starved”
because
they
are
not
served.
Weighted
Round
‐
Robin
(WRR)
(8:4:2:1):
WRR
queue
‐
scheduling
algorithm
schedules
all
the
queues
in
turn
and
every
queue
can
be
assured
of
a
certain
service
time.
Assume
there
are
four
priority
queues
on
a
port.
WRR
configures
a
weight
value
for
each
queue,
which
is
Q1
、
Q2
、
Q3
and
Q4
.
The
weight
value
indicates
the
proportion
of
obtaining
resources.
On
a
150
M
port,
configure
the
weight
value
of
WRR
queue
‐
scheduling
algorithm
to
1
、
2
、
4
and
8
(corresponding
to
Q1
、
Q2
、
Q3
and
Q4
in
order).
In
this
way,
the
queue
with
the
lowest
priority
can
get
10
Mbps
bandwidth
at
least,
and
the
disadvantage
of
SP
queue
‐
scheduling
that
the
packets
in
queues
with
lower
priority
may
not
get
service
for
a
long
time
is
avoided.
Another
advantage
of
WRR
queue
is
that:
though
the
queues
are
scheduled
in
order,
the
service
time
for
each
queue
is
not
fixed;
that
is
to
say,
if
a
queue
is
empty,
the
next
queue
will
be
scheduled.
In
this
way,
the
bandwidth
resources
are
made
full
use.
8.3
Transmit
Queues
This
page
sets
the
local
precedence
for
802.1p
priority.
The
following
table
lists
the
default
mapping
between
802.1p
priority
and
local
precedence:
802.1p
priority
Local
precedence
0
Q0
1
Q0
2
Q1
3
Q1
4
Q2
5
Q2
6
Q3
7
Q3
