<s>
In	O
packet	B-Protocol
switching	I-Protocol
networks	O
,	O
traffic	B-Operating_System
flow	I-Operating_System
,	O
packet	B-Operating_System
flow	I-Operating_System
or	O
network	B-Algorithm
flow	I-Algorithm
is	O
a	O
sequence	O
of	O
packets	B-Protocol
from	O
a	O
source	O
computer	O
to	O
a	O
destination	O
,	O
which	O
may	O
be	O
another	O
host	O
,	O
a	O
multicast	O
group	O
,	O
or	O
a	O
broadcast	B-Operating_System
domain	O
.	O
</s>
<s>
RFC	O
2722	O
defines	O
traffic	B-Operating_System
flow	I-Operating_System
as	O
"	O
an	O
artificial	O
logical	O
equivalent	O
to	O
a	O
call	O
or	O
connection.	O
"	O
</s>
<s>
RFC	O
3697	O
defines	O
traffic	B-Operating_System
flow	I-Operating_System
as	O
"	O
a	O
sequence	O
of	O
packets	B-Protocol
sent	O
from	O
a	O
particular	O
source	O
to	O
a	O
particular	O
unicast	O
,	O
anycast	O
,	O
or	O
multicast	O
destination	O
that	O
the	O
source	O
desires	O
to	O
label	O
as	O
a	O
flow	O
.	O
</s>
<s>
A	O
flow	O
could	O
consist	O
of	O
all	O
packets	B-Protocol
in	O
a	O
specific	O
transport	O
connection	O
or	O
a	O
media	O
stream	O
.	O
</s>
<s>
Flow	O
is	O
also	O
defined	O
in	O
RFC	O
3917	O
as	O
"	O
a	O
set	O
of	O
IP	O
packets	B-Protocol
passing	O
an	O
observation	O
point	O
in	O
the	O
network	O
during	O
a	O
certain	O
time	O
interval.	O
"	O
</s>
<s>
Packet	B-Operating_System
flow	I-Operating_System
temporal	O
efficiency	O
can	O
be	O
affected	O
by	O
one-way	O
delay	O
(	O
OWD	O
)	O
that	O
is	O
described	O
as	O
a	O
combination	O
of	O
the	O
following	O
components	O
:	O
</s>
<s>
Packets	B-Protocol
from	O
one	O
flow	O
need	O
to	O
be	O
handled	O
differently	O
from	O
others	O
,	O
by	O
means	O
of	O
separate	O
queues	O
in	O
switches	B-Protocol
,	O
routers	B-Protocol
and	O
network	B-Protocol
adapters	I-Protocol
,	O
to	O
achieve	O
traffic	O
shaping	O
,	O
policing	O
,	O
fair	B-Algorithm
queueing	I-Algorithm
or	O
quality	O
of	O
service	O
.	O
</s>
<s>
It	O
is	O
also	O
a	O
concept	O
used	O
in	O
Queueing	O
Network	O
Analyzers	O
(	O
QNAs	O
)	O
or	O
in	O
packet	B-Protocol
tracing	O
.	O
</s>
<s>
Applied	O
to	O
Internet	B-Protocol
routers	I-Protocol
,	O
a	O
flow	O
may	O
be	O
a	O
host-to-host	O
communication	O
path	O
,	O
or	O
a	O
socket-to-socket	B-Protocol
communication	O
identified	O
by	O
a	O
unique	O
combination	O
of	O
source	O
and	O
destination	O
addresses	O
and	O
port	O
numbers	O
,	O
together	O
with	O
transport	O
protocol	O
(	O
for	O
example	O
,	O
UDP	B-Protocol
or	O
TCP	B-Protocol
)	O
.	O
</s>
<s>
In	O
the	O
TCP	B-Protocol
case	O
,	O
a	O
flow	O
may	O
be	O
a	O
virtual	B-Protocol
circuit	I-Protocol
,	O
also	O
known	O
as	O
a	O
virtual	B-Protocol
connection	I-Protocol
or	O
a	O
byte	O
stream	O
.	O
</s>
<s>
In	O
packet	B-Protocol
switches	I-Protocol
,	O
the	O
flow	O
may	O
be	O
identified	O
by	O
IEEE	O
802.1Q	O
Virtual	O
LAN	O
tagging	O
in	O
Ethernet	O
networks	O
,	O
or	O
by	O
a	O
Label	O
Switched	O
Path	O
in	O
MPLS	B-Protocol
tag	B-Protocol
switching	I-Protocol
.	O
</s>
<s>
Packet	B-Operating_System
flow	I-Operating_System
can	O
be	O
represented	O
as	O
a	O
path	O
in	O
a	O
network	O
to	O
model	O
network	O
performance	O
.	O
</s>
<s>
For	O
example	O
,	O
a	O
water	O
flow	B-Algorithm
network	I-Algorithm
can	O
be	O
used	O
to	O
conceptualize	O
packet	B-Operating_System
flow	I-Operating_System
.	O
</s>
