<s>
Low	B-Protocol
Extra	I-Protocol
Delay	I-Protocol
Background	I-Protocol
Transport	I-Protocol
(	O
LEDBAT	B-Protocol
)	O
is	O
a	O
way	O
to	O
transfer	O
data	O
on	O
the	O
Internet	O
quickly	O
without	O
clogging	O
the	O
network	O
.	O
</s>
<s>
LEDBAT	B-Protocol
was	O
invented	O
by	O
Stanislav	O
Shalunov	O
and	O
is	O
used	O
by	O
Apple	O
for	O
software	O
updates	O
,	O
by	O
BitTorrent	B-Protocol
for	O
most	O
of	O
its	O
transfers	O
and	O
by	O
Microsoft	B-Protocol
SCCM	I-Protocol
software	O
distribution	O
points	O
.	O
</s>
<s>
At	O
one	O
point	O
in	O
time	O
,	O
LEDBAT	B-Protocol
was	O
estimated	O
to	O
carry	O
13	O
–	O
20%	O
of	O
Internet	O
traffic	O
.	O
</s>
<s>
LEDBAT	B-Protocol
is	O
a	O
delay-based	O
congestion	O
control	O
algorithm	O
that	O
uses	O
all	O
the	O
available	O
bandwidth	O
while	O
limiting	O
the	O
increase	O
in	O
delay	O
;	O
it	O
does	O
so	O
by	O
measuring	O
one-way	B-Protocol
delay	I-Protocol
and	O
using	O
changes	O
in	O
the	O
measurements	O
to	O
limit	O
congestion	O
that	O
the	O
LEDBAT	B-Protocol
flow	O
itself	O
induces	O
in	O
the	O
network	O
.	O
</s>
<s>
LEDBAT	B-Protocol
is	O
described	O
in	O
RFC	O
6817	O
.	O
</s>
<s>
LEDBAT	B-Protocol
congestion	O
control	O
has	O
the	O
following	O
goals	O
:	O
</s>
<s>
Use	O
all	O
available	O
bandwidth	O
,	O
and	O
to	O
maintain	O
a	O
low	O
queueing	B-Protocol
delay	I-Protocol
when	O
no	O
other	O
traffic	O
is	O
present	O
,	O
</s>
<s>
To	O
yield	O
quickly	O
to	O
standard	O
TCP	O
that	O
share	O
the	O
same	O
bottleneck	B-Protocol
link	I-Protocol
.	O
</s>
<s>
The	O
two	O
main	O
implementations	O
are	O
uTP	B-Protocol
by	O
BitTorrent	B-Protocol
and	O
as	O
part	O
of	O
TCP	O
by	O
Apple	O
.	O
</s>
<s>
BitTorrent	B-Protocol
uses	O
uTP	B-Protocol
for	O
most	O
traffic	O
and	O
makes	O
the	O
code	O
available	O
under	O
an	O
open-source	O
license	O
.	O
</s>
<s>
Apple	O
uses	O
LEDBAT	B-Protocol
for	O
Software	O
Updates	O
so	O
that	O
large	O
software	O
downloads	O
to	O
macOS	B-Application
computers	O
and	O
iOS	B-Operating_System
devices	I-Operating_System
do	O
not	O
interfere	O
with	O
normal	O
user	O
activities	O
;	O
Apple	O
also	O
makes	O
the	O
source	O
code	O
available	O
.	O
</s>
<s>
Both	O
of	O
the	O
above	O
implementations	O
aim	O
to	O
limit	O
the	O
network	O
queuing	B-Protocol
delay	I-Protocol
to	O
100ms	O
.	O
</s>
<s>
Windows	B-Operating_System
10	I-Operating_System
Anniversary	O
Update	O
introduced	O
support	O
for	O
LEDBAT	B-Protocol
via	O
undocumented	O
socket	O
option	O
as	O
an	O
experimental	O
Windows	O
TCP	O
Congestion	O
Control	O
Module	O
and	O
Windows	B-Device
Server	I-Device
2019	I-Device
.	O
</s>
