<s>
The	O
Virtual	B-General_Concept
Interface	I-General_Concept
Architecture	I-General_Concept
(	O
VIA	O
)	O
is	O
an	O
abstract	O
model	O
of	O
a	O
user-level	O
zero-copy	O
network	B-Architecture
,	O
and	O
is	O
the	O
basis	O
for	O
InfiniBand	B-Architecture
,	O
iWARP	B-Device
and	O
RoCE	B-Operating_System
.	O
</s>
<s>
Created	O
by	O
Microsoft	O
,	O
Intel	O
,	O
and	O
Compaq	O
,	O
the	O
original	O
VIA	O
sought	O
to	O
standardize	O
the	O
interface	O
for	O
high-performance	O
network	B-Architecture
technologies	O
known	O
as	O
System	B-General_Concept
Area	I-General_Concept
Networks	I-General_Concept
(	O
SANs	O
;	O
not	O
to	O
be	O
confused	O
with	O
Storage	O
Area	O
Networks	O
)	O
.	O
</s>
<s>
With	O
traditional	O
network	B-Architecture
APIs	O
such	O
as	O
the	O
Berkeley	B-Protocol
socket	I-Protocol
API	I-Protocol
,	O
the	O
kernel	B-Operating_System
is	O
involved	O
in	O
every	O
network	B-Architecture
communication	O
.	O
</s>
<s>
One	O
of	O
the	O
classic	O
developments	O
in	O
computing	O
systems	O
is	O
virtual	B-Architecture
memory	I-Architecture
,	O
a	O
combination	O
of	O
hardware	O
and	O
software	O
that	O
creates	O
the	O
illusion	O
of	O
private	O
memory	O
for	O
each	O
process	O
.	O
</s>
<s>
In	O
the	O
same	O
school	O
of	O
thought	O
,	O
a	O
virtual	O
network	B-Architecture
interface	O
protected	O
across	O
process	O
boundaries	O
could	O
be	O
accessed	O
at	O
the	O
user	O
level	O
.	O
</s>
<s>
Thus	O
,	O
the	O
network	B-Protocol
interface	I-Protocol
card	I-Protocol
(	O
NIC	O
)	O
provides	O
a	O
"	O
private	O
network	B-Architecture
"	O
for	O
a	O
process	O
,	O
and	O
a	O
process	O
is	O
usually	O
allowed	O
to	O
have	O
multiple	O
such	O
networks	O
.	O
</s>
<s>
The	O
virtual	O
interface	O
(	O
VI	O
)	O
of	O
VIA	O
refers	O
to	O
this	O
network	B-Architecture
and	O
is	O
merely	O
the	O
destination	O
of	O
the	O
user	O
's	O
communication	O
requests	O
.	O
</s>
<s>
In	O
"	O
kernel-bypass	O
"	O
communication	O
,	O
the	O
user	O
manages	O
its	O
own	O
buffers	O
.	O
</s>
<s>
Another	O
classic	O
development	O
in	O
computing	O
systems	O
is	O
direct	B-General_Concept
memory	I-General_Concept
access	I-General_Concept
(	O
DMA	O
)	O
,	O
in	O
which	O
a	O
device	O
can	O
access	O
main	O
memory	O
directly	O
while	O
the	O
CPU	O
is	O
free	O
to	O
perform	O
other	O
tasks	O
.	O
</s>
<s>
In	O
a	O
network	B-Architecture
with	O
"	O
remote	B-General_Concept
direct	I-General_Concept
memory	I-General_Concept
access	I-General_Concept
"	O
(	O
RDMA	B-General_Concept
)	O
,	O
the	O
sending	O
NIC	O
uses	O
DMA	O
to	O
read	O
data	O
in	O
the	O
user-specified	O
buffer	O
and	O
transmit	O
it	O
as	O
a	O
self-contained	O
message	O
across	O
the	O
network	B-Architecture
.	O
</s>
<s>
This	O
action	O
—	O
one	O
of	O
the	O
few	O
that	O
involve	O
the	O
kernel	B-Operating_System
—	O
ties	O
the	O
page	O
to	O
physical	O
memory	O
.	O
</s>
<s>
So	O
essentially	O
VIA	O
is	O
a	O
standard	O
that	O
defines	O
kernel	B-Operating_System
bypassing	O
and	O
RDMA	B-General_Concept
in	O
a	O
network	B-Architecture
.	O
</s>
<s>
Mostly	O
though	O
,	O
VIA	O
's	O
major	O
contribution	O
has	O
been	O
in	O
providing	O
a	O
basis	O
for	O
the	O
InfiniBand	B-Architecture
,	O
iWARP	B-Device
and	O
RoCE	B-Operating_System
standards	O
.	O
</s>
