<s>
Tail	B-Protocol
drop	I-Protocol
is	O
a	O
simple	O
queue	O
management	O
algorithm	O
used	O
by	O
network	B-Application
schedulers	I-Application
in	O
network	B-Device
equipment	I-Device
to	O
decide	O
when	O
to	O
drop	O
packets	B-Protocol
.	O
</s>
<s>
With	O
tail	B-Protocol
drop	I-Protocol
,	O
when	O
the	O
queue	O
is	O
filled	O
to	O
its	O
maximum	O
capacity	O
,	O
the	O
newly	O
arriving	O
packets	B-Protocol
are	O
dropped	O
until	O
the	O
queue	O
has	O
enough	O
room	O
to	O
accept	O
incoming	O
traffic	O
.	O
</s>
<s>
The	O
name	O
arises	O
from	O
the	O
effect	O
of	O
the	O
policy	O
on	O
incoming	O
packets	B-Protocol
.	O
</s>
<s>
Once	O
a	O
queue	O
has	O
been	O
filled	O
,	O
the	O
router	O
begins	O
discarding	O
all	O
additional	O
datagrams	O
,	O
thus	O
dropping	O
the	O
tail	O
of	O
the	O
sequence	O
of	O
packets	B-Protocol
.	O
</s>
<s>
The	O
loss	O
of	O
packets	B-Protocol
causes	O
the	O
TCP	B-Protocol
sender	O
to	O
enter	O
slow	O
start	O
,	O
which	O
reduces	O
throughput	O
in	O
that	O
TCP	B-Protocol
session	O
until	O
the	O
sender	O
begins	O
to	O
receive	O
acknowledgements	B-Protocol
again	O
and	O
increases	O
its	O
congestion	O
window	O
.	O
</s>
<s>
A	O
more	O
severe	O
problem	O
occurs	O
when	O
datagrams	O
from	O
multiple	O
TCP	B-Protocol
connections	O
are	O
dropped	O
,	O
causing	O
global	B-Protocol
synchronization	I-Protocol
;	O
i.e.	O
</s>
<s>
all	O
of	O
the	O
involved	O
TCP	B-Protocol
senders	O
enter	O
slow-start	O
.	O
</s>
<s>
This	O
happens	O
because	O
,	O
instead	O
of	O
discarding	O
many	O
segments	B-Protocol
from	O
one	O
connection	O
,	O
the	O
router	O
would	O
tend	O
to	O
discard	O
one	O
segment	O
from	O
each	O
connection	O
.	O
</s>
