<s>
Random	B-Algorithm
early	I-Algorithm
detection	I-Algorithm
(	O
RED	O
)	O
,	O
also	O
known	O
as	O
random	B-Algorithm
early	I-Algorithm
discard	I-Algorithm
or	O
random	B-Algorithm
early	I-Algorithm
drop	I-Algorithm
is	O
a	O
queuing	B-Application
discipline	I-Application
for	O
a	O
network	B-Application
scheduler	I-Application
suited	O
for	O
congestion	O
avoidance	O
.	O
</s>
<s>
In	O
the	O
conventional	O
tail	B-Protocol
drop	I-Protocol
algorithm	O
,	O
a	O
router	B-Protocol
or	O
other	O
network	B-Device
component	I-Device
buffers	O
as	O
many	O
packets	O
as	O
it	O
can	O
,	O
and	O
simply	O
drops	O
the	O
ones	O
it	O
cannot	O
buffer	O
.	O
</s>
<s>
If	O
buffers	O
are	O
constantly	O
full	O
,	O
the	O
network	O
is	O
congested	B-Protocol
.	O
</s>
<s>
Tail	B-Protocol
drop	I-Protocol
distributes	O
buffer	O
space	O
unfairly	O
among	O
traffic	O
flows	O
.	O
</s>
<s>
Tail	B-Protocol
drop	I-Protocol
can	O
also	O
lead	O
to	O
TCP	B-Protocol
global	I-Protocol
synchronization	I-Protocol
as	O
all	O
TCP	B-Protocol
connections	O
"	O
hold	O
back	O
"	O
simultaneously	O
,	O
and	O
then	O
step	O
forward	O
simultaneously	O
.	O
</s>
<s>
RED	O
is	O
more	O
fair	O
than	O
tail	B-Protocol
drop	I-Protocol
,	O
in	O
the	O
sense	O
that	O
it	O
does	O
not	O
possess	O
a	O
bias	O
against	O
bursty	O
traffic	O
that	O
uses	O
only	O
a	O
small	O
portion	O
of	O
the	O
bandwidth	O
.	O
</s>
<s>
Early	O
detection	O
helps	O
avoid	O
TCP	B-Protocol
global	I-Protocol
synchronization	I-Protocol
.	O
</s>
<s>
Robust	O
random	B-Algorithm
early	I-Algorithm
detection	I-Algorithm
(	O
RRED	O
)	O
algorithm	O
was	O
proposed	O
to	O
improve	O
the	O
TCP	B-Protocol
throughput	O
against	O
Denial-of-Service	O
(	O
DoS	O
)	O
attacks	O
,	O
particularly	O
(	O
LDoS	O
)	O
attacks	O
.	O
</s>
<s>
Experiments	O
have	O
confirmed	O
that	O
the	O
existing	O
RED-like	O
algorithms	O
are	O
notably	O
vulnerable	O
under	O
Low-rate	O
Denial-of-Service	O
(	O
LDoS	O
)	O
attacks	O
due	O
to	O
the	O
oscillating	O
TCP	B-Protocol
queue	O
size	O
caused	O
by	O
the	O
attacks	O
.	O
</s>
<s>
RRED	O
algorithm	O
can	O
significantly	O
improve	O
the	O
performance	O
of	O
TCP	B-Protocol
under	O
Low-rate	O
Denial-of-Service	O
attacks	O
.	O
</s>
