<s>
The	O
C10k	B-Protocol
problem	I-Protocol
is	O
the	O
problem	O
of	O
optimizing	O
network	B-Protocol
sockets	I-Protocol
to	O
handle	O
a	O
large	O
number	O
of	O
clients	O
at	O
the	O
same	O
time	O
.	O
</s>
<s>
The	O
name	O
C10k	B-Protocol
is	O
a	O
numeronym	O
for	O
concurrently	B-Architecture
handling	O
ten	O
thousand	O
connections	O
.	O
</s>
<s>
According	O
to	O
the	O
scope	O
of	O
services	O
to	O
be	O
made	O
available	O
and	O
the	O
capabilities	O
of	O
the	O
operating	O
system	O
as	O
well	O
as	O
hardware	O
considerations	O
such	O
as	O
multi-processing	O
capabilities	O
,	O
a	O
multi-threading	O
model	O
or	O
a	O
single	B-Operating_System
threading	I-Operating_System
model	O
can	O
be	O
preferred	O
.	O
</s>
<s>
Concurrently	B-Architecture
with	O
this	O
aspect	O
,	O
which	O
involves	O
considerations	O
regarding	O
memory	O
management	O
(	O
usually	O
operating	O
system	O
related	O
)	O
,	O
strategies	O
implied	O
relate	O
to	O
the	O
very	O
diverse	O
aspects	O
of	O
the	O
I/O	O
management	O
.	O
</s>
<s>
The	O
term	O
C10k	B-Protocol
was	O
coined	O
in	O
1999	O
by	O
software	O
engineer	O
Dan	O
Kegel	O
,	O
citing	O
the	O
Simtel	B-Application
FTP	B-Protocol
host	O
,	O
cdrom.com,	O
serving	O
10,000	O
clients	O
at	O
once	O
over	O
1	O
gigabit	O
per	O
second	O
Ethernet	O
in	O
that	O
year	O
.	O
</s>
<s>
By	O
the	O
early	O
2010s	O
millions	O
of	O
connections	O
on	O
a	O
single	O
commodity	O
1U	O
rackmount	O
server	O
became	O
possible	O
:	O
over	O
2	O
million	O
connections	O
(	O
WhatsApp	B-Application
,	O
24	O
cores	O
,	O
using	O
Erlang	B-Operating_System
on	O
FreeBSD	B-Operating_System
)	O
,	O
10	O
–	O
12	O
million	O
connections	O
(	O
MigratoryData	O
,	O
12	O
cores	O
,	O
using	O
Java	B-Language
on	O
Linux	B-Application
)	O
.	O
</s>
<s>
Common	O
applications	O
of	O
very	O
high	O
number	O
of	O
connections	O
include	O
general	O
public	O
servers	O
,	O
or	O
private	O
servers	O
of	O
very	O
big	O
companies	O
whose	O
sparse	O
offices	O
are	O
connected	O
to	O
those	O
servers	O
via	O
their	O
virtual	B-Application
private	I-Application
networks	I-Application
,	O
that	O
have	O
to	O
serve	O
thousands	O
or	O
even	O
millions	O
of	O
users	O
at	O
a	O
time	O
,	O
such	O
as	O
file	B-Application
servers	I-Application
,	O
FTP	B-Protocol
servers	I-Protocol
,	O
proxy	B-Application
servers	I-Application
,	O
web	O
servers	O
,	O
load	B-Application
balancers	I-Application
,	O
and	O
so	O
on	O
.	O
</s>
