<s>
Equal-cost	B-Protocol
multi-path	I-Protocol
routing	I-Protocol
(	O
ECMP	O
)	O
is	O
a	O
routing	B-Protocol
strategy	O
where	O
packet	B-Protocol
forwarding	I-Protocol
to	O
a	O
single	O
destination	O
can	O
occur	O
over	O
multiple	O
best	O
paths	O
with	O
equal	O
routing	B-Protocol
priority	O
.	O
</s>
<s>
Multi-path	B-Protocol
routing	I-Protocol
can	O
be	O
used	O
in	O
conjunction	O
with	O
most	O
routing	B-Protocol
protocols	O
because	O
it	O
is	O
a	O
per-hop	O
local	O
decision	O
made	O
independently	O
at	O
each	O
router	O
.	O
</s>
<s>
It	O
can	O
substantially	O
increase	O
bandwidth	O
by	O
load-balancing	B-Application
traffic	O
over	O
multiple	O
paths	O
;	O
however	O
,	O
there	O
may	O
be	O
significant	O
problems	O
in	O
deploying	O
it	O
in	O
practice	O
.	O
</s>
<s>
Load	B-Application
balancing	I-Application
by	O
per-packet	O
multipath	B-Protocol
routing	I-Protocol
was	O
generally	O
disfavored	O
due	O
to	O
the	O
impact	O
of	O
rapidly	O
changing	O
latency	O
,	O
packet	B-Protocol
reordering	I-Protocol
and	O
maximum	B-Protocol
transmission	I-Protocol
unit	I-Protocol
(	O
MTU	B-Protocol
)	O
differences	O
within	O
a	O
network	O
flow	O
,	O
which	O
could	O
disrupt	O
the	O
operation	O
of	O
many	O
Internet	O
protocols	O
,	O
most	O
notably	O
TCP	B-Protocol
and	O
path	B-Protocol
MTU	I-Protocol
discovery	I-Protocol
.	O
</s>
<s>
RFC	O
2992	O
analyzed	O
one	O
particular	O
multipath	B-Protocol
routing	I-Protocol
strategy	O
involving	O
the	O
assignment	O
of	O
flows	B-Operating_System
through	O
hashing	B-Error_Name
flow-related	O
data	O
in	O
the	O
packet	B-General_Concept
header	I-General_Concept
.	O
</s>
<s>
This	O
solution	O
is	O
designed	O
to	O
avoid	O
these	O
problems	O
by	O
sending	O
all	O
packets	O
from	O
any	O
particular	O
network	O
flow	O
through	O
the	O
same	O
path	O
while	O
balancing	O
multiple	O
flows	B-Operating_System
over	O
multiple	O
paths	O
in	O
general	O
.	O
</s>
