<s>
Weighted	B-Algorithm
round	I-Algorithm
robin	I-Algorithm
(	O
WRR	O
)	O
is	O
a	O
network	B-Application
scheduler	I-Application
for	O
data	O
flows	O
,	O
but	O
also	O
used	O
to	O
schedule	O
processes	O
.	O
</s>
<s>
Weighted	B-Algorithm
round	I-Algorithm
robin	I-Algorithm
is	O
a	O
generalisation	O
of	O
round-robin	B-Algorithm
scheduling	I-Algorithm
.	O
</s>
<s>
Whereas	O
round-robin	B-Algorithm
cycles	O
over	O
the	O
queues	O
or	O
tasks	O
and	O
gives	O
one	O
service	O
opportunity	O
per	O
cycle	O
,	O
weighted	B-Algorithm
round	I-Algorithm
robin	I-Algorithm
offers	O
to	O
each	O
a	O
fixed	O
number	O
of	O
opportunities	O
,	O
as	O
specified	O
by	O
the	O
configured	O
weight	O
which	O
serves	O
to	O
influence	O
the	O
portion	O
of	O
capacity	O
received	O
by	O
each	O
queue	O
or	O
task	O
.	O
</s>
<s>
If	O
all	O
packets	O
have	O
the	O
same	O
size	O
,	O
WRR	O
is	O
the	O
simplest	O
approximation	O
of	O
generalized	B-Algorithm
processor	I-Algorithm
sharing	I-Algorithm
(	O
GPS	O
)	O
.	O
</s>
<s>
WRR	O
is	O
presented	O
in	O
the	O
following	O
as	O
a	O
network	B-Application
scheduler	I-Application
.	O
</s>
<s>
A	O
weighted	O
round-robin	B-Algorithm
network	B-Application
scheduler	I-Application
has	O
input	O
queues	O
,	O
.	O
</s>
<s>
Like	O
round-robin	B-Algorithm
,	O
weighted	B-Algorithm
round	I-Algorithm
robin	I-Algorithm
scheduling	O
is	O
simple	O
,	O
easy	O
to	O
implement	O
,	O
work	B-General_Concept
conserving	I-General_Concept
and	O
starvation-free	B-Operating_System
.	O
</s>
<s>
When	O
scheduling	O
packets	O
,	O
if	O
all	O
packets	O
have	O
the	O
same	O
size	O
,	O
then	O
WRR	O
and	O
IWRR	O
are	O
an	O
approximation	O
of	O
Generalized	B-Algorithm
processor	I-Algorithm
sharing	I-Algorithm
:	O
a	O
queue	O
will	O
receive	O
a	O
long	O
term	O
part	O
of	O
the	O
bandwidth	O
equals	O
to	O
(	O
if	O
all	O
queues	O
are	O
active	O
)	O
while	O
GPS	O
serves	O
infinitesimal	O
amounts	O
of	O
data	O
from	O
each	O
nonempty	O
queue	O
and	O
offer	O
this	O
part	O
on	O
any	O
interval	O
.	O
</s>
<s>
The	O
primary	O
limitation	O
of	O
weighted	O
round-robin	B-Algorithm
queuing	O
is	O
that	O
it	O
provides	O
the	O
correct	O
percentage	O
of	O
bandwidth	O
to	O
each	O
service	O
class	O
only	O
if	O
all	O
the	O
packets	O
in	O
all	O
the	O
queues	O
are	O
the	O
same	O
size	O
or	O
when	O
the	O
mean	O
packet	O
size	O
is	O
known	O
in	O
advance	O
.	O
</s>
<s>
In	O
the	O
more	O
general	O
case	O
of	O
IP	B-Protocol
networks	I-Protocol
with	O
variable	O
size	O
packets	O
,	O
to	O
approximate	O
GPS	O
the	O
weight	O
factors	O
must	O
be	O
adjusted	O
based	O
on	O
the	O
packet	O
size	O
.	O
</s>
<s>
Deficit	B-Algorithm
round	I-Algorithm
robin	I-Algorithm
is	O
a	O
later	O
variation	O
of	O
WRR	O
that	O
achieves	O
better	O
GPS	O
approximation	O
without	O
knowing	O
the	O
mean	O
packet	O
size	O
of	O
each	O
connection	O
in	O
advance	O
.	O
</s>
<s>
weighted	B-Algorithm
fair	I-Algorithm
queuing	I-Algorithm
)	O
.	O
</s>
