<s>
Internet	B-Protocol
Protocol	I-Protocol
Flow	O
Information	O
Export	O
(	O
IPFIX	B-Protocol
)	O
is	O
an	O
IETF	O
protocol	O
,	O
as	O
well	O
as	O
the	O
name	O
of	O
the	O
IETF	O
working	O
group	O
defining	O
the	O
protocol	O
.	O
</s>
<s>
It	O
was	O
created	O
based	O
on	O
the	O
need	O
for	O
a	O
common	O
,	O
universal	O
standard	O
of	O
export	O
for	O
Internet	B-Protocol
Protocol	I-Protocol
flow	O
information	O
from	O
routers	B-Protocol
,	O
probes	O
and	O
other	O
devices	O
that	O
are	O
used	O
by	O
mediation	O
systems	O
,	O
accounting/billing	O
systems	O
and	O
network	O
management	O
systems	O
to	O
facilitate	O
services	O
such	O
as	O
measurement	O
,	O
accounting	O
and	O
billing	O
.	O
</s>
<s>
The	O
IPFIX	B-Protocol
standard	O
defines	O
how	O
IP	O
flow	O
information	O
is	O
to	O
be	O
formatted	O
and	O
transferred	O
from	O
an	O
exporter	O
to	O
a	O
collector	O
.	O
</s>
<s>
Previously	O
many	O
data	O
network	O
operators	O
were	O
relying	O
on	O
Cisco	O
Systems	O
 '	O
proprietary	O
NetFlow	B-Protocol
technology	O
for	O
traffic	O
flow	O
information	O
export	O
.	O
</s>
<s>
The	O
IPFIX	B-Protocol
standards	O
requirements	O
were	O
outlined	O
in	O
the	O
original	O
RFC	O
3917	O
.	O
</s>
<s>
Cisco	O
NetFlow	B-Protocol
Version	O
9	O
was	O
the	O
basis	O
for	O
IPFIX	B-Protocol
.	O
</s>
<s>
The	O
basic	O
specifications	O
for	O
IPFIX	B-Protocol
are	O
documented	O
in	O
RFC	O
7011	O
through	O
RFC	O
7015	O
,	O
and	O
RFC	O
5103	O
.	O
</s>
<s>
The	O
following	O
figure	O
shows	O
a	O
typical	O
architecture	O
of	O
information	O
flow	O
in	O
an	O
IPFIX	B-Protocol
architecture	O
:	O
</s>
<s>
An	O
Exporter	O
then	O
gathers	O
each	O
of	O
the	O
Observation	O
Points	O
together	O
into	O
an	O
Observation	O
Domain	O
and	O
sends	O
this	O
information	O
via	O
the	O
IPFIX	B-Protocol
protocol	O
to	O
a	O
Collector	O
.	O
</s>
<s>
Exporters	O
and	O
Collectors	O
are	O
in	O
a	O
many-to-many	B-Architecture
relationship	O
:	O
One	O
Exporter	O
can	O
send	O
data	O
to	O
many	O
Collectors	O
and	O
one	O
Collector	O
can	O
receive	O
data	O
from	O
many	O
Exporters	O
.	O
</s>
<s>
Similar	O
to	O
the	O
NetFlow	B-Protocol
Protocol	O
,	O
IPFIX	B-Protocol
considers	O
a	O
flow	O
to	O
be	O
any	O
number	O
of	O
packets	O
observed	O
in	O
a	O
specific	O
timeslot	O
and	O
sharing	O
a	O
number	O
of	O
properties	O
,	O
e.g.	O
</s>
<s>
Using	O
IPFIX	B-Protocol
,	O
devices	O
like	O
routers	B-Protocol
can	O
inform	O
a	O
central	O
monitoring	O
station	O
about	O
their	O
view	O
of	O
a	O
potentially	O
larger	O
network	O
.	O
</s>
<s>
IPFIX	B-Protocol
is	O
a	O
push	O
protocol	O
,	O
i.e.	O
</s>
<s>
each	O
sender	O
will	O
periodically	O
send	O
IPFIX	B-Protocol
messages	O
to	O
configured	O
receivers	O
without	O
any	O
interaction	O
by	O
the	O
receiver	O
.	O
</s>
<s>
The	O
actual	O
makeup	O
of	O
data	O
in	O
IPFIX	B-Protocol
messages	O
is	O
to	O
a	O
great	O
extent	O
up	O
to	O
the	O
sender	O
.	O
</s>
<s>
IPFIX	B-Protocol
introduces	O
the	O
makeup	O
of	O
these	O
messages	O
to	O
the	O
receiver	O
with	O
the	O
help	O
of	O
special	O
Templates	O
.	O
</s>
<s>
IPFIX	B-Protocol
prefers	O
the	O
Stream	B-Protocol
Control	I-Protocol
Transmission	I-Protocol
Protocol	I-Protocol
(	O
SCTP	B-Protocol
)	O
as	O
its	O
transport	B-Architecture
layer	I-Architecture
protocol	O
,	O
but	O
also	O
allows	O
the	O
use	O
of	O
the	O
Transmission	B-Protocol
Control	I-Protocol
Protocol	I-Protocol
(	O
TCP	O
)	O
or	O
User	B-Protocol
Datagram	I-Protocol
Protocol	I-Protocol
(	O
UDP	O
)	O
.	O
</s>
<s>
A	O
simple	O
information	O
set	O
sent	O
via	O
IPFIX	B-Protocol
might	O
look	O
like	O
this	O
:	O
</s>
<s>
This	O
information	O
set	O
would	O
be	O
sent	O
in	O
the	O
following	O
IPFIX	B-Protocol
message	O
:	O
</s>
<s>
As	O
can	O
be	O
seen	O
,	O
the	O
message	O
contains	O
the	O
IPFIX	B-Protocol
header	O
and	O
two	O
IPFIX	B-Protocol
Sets	O
:	O
One	O
Template	O
Set	O
that	O
introduces	O
the	O
build-up	O
of	O
the	O
Data	O
Set	O
used	O
,	O
as	O
well	O
as	O
one	O
Data	O
Set	O
,	O
which	O
contains	O
the	O
actual	O
data	O
.	O
</s>
<s>
When	O
IPFIX	B-Protocol
is	O
sent	O
over	O
a	O
protocol	O
which	O
keeps	O
a	O
session	O
state	O
(	O
TCP	O
or	O
SCTP	B-Protocol
)	O
,	O
the	O
Template	O
Set	O
need	O
not	O
be	O
retransmitted	O
since	O
it	O
is	O
buffered	O
in	O
Collectors	O
.	O
</s>
<s>
Since	O
the	O
Template	O
Set	O
can	O
change	O
over	O
time	O
,	O
it	O
must	O
be	O
retransmitted	O
if	O
a	O
new	O
session	O
state	O
is	O
established	O
or	O
if	O
IPFIX	B-Protocol
is	O
sent	O
over	O
UDP	O
which	O
is	O
a	O
session-less	O
protocol	O
.	O
</s>
