<s>
6LoWPAN	B-Protocol
(	O
acronym	O
of	O
"	O
IPv6	B-Protocol
over	O
Low-Power	O
Wireless	B-General_Concept
Personal	I-General_Concept
Area	I-General_Concept
Networks	I-General_Concept
"	O
)	O
was	O
a	O
working	O
group	O
of	O
the	O
Internet	O
Engineering	O
Task	O
Force	O
(	O
IETF	O
)	O
.	O
</s>
<s>
It	O
was	O
created	O
with	O
the	O
intention	O
of	O
applying	O
the	O
Internet	B-Protocol
Protocol	I-Protocol
(	O
IP	O
)	O
even	O
to	O
the	O
smallest	O
devices	O
,	O
enabling	O
low-power	O
devices	O
with	O
limited	O
processing	O
capabilities	O
to	O
participate	O
in	O
the	B-Operating_System
Internet	I-Operating_System
of	I-Operating_System
Things	I-Operating_System
.	O
</s>
<s>
The	O
6LoWPAN	B-Protocol
group	O
defined	O
encapsulation	O
,	O
header	O
compression	O
,	O
neighbor	B-Protocol
discovery	I-Protocol
and	O
other	O
mechanisms	O
that	O
allow	O
IPv6	B-Protocol
to	O
operate	O
over	O
IEEE	O
802.15.4	O
based	O
networks	O
.	O
</s>
<s>
Although	O
IPv4	B-Protocol
and	O
IPv6	B-Protocol
protocols	O
do	O
not	O
generally	O
care	O
about	O
the	O
physical	B-Application
and	O
MAC	B-Protocol
layers	I-Protocol
they	O
operate	O
over	O
,	O
the	O
low	O
power	O
devices	O
and	O
small	O
packet	O
size	O
defined	O
by	O
IEEE	O
802.15.4	O
make	O
it	O
desirable	O
to	O
adapt	O
to	O
these	O
layers	O
.	O
</s>
<s>
The	O
base	O
specification	O
developed	O
by	O
the	O
6LoWPAN	B-Protocol
IETF	O
group	O
is	O
(	O
updated	O
by	O
with	O
header	O
compression	O
,	O
with	O
neighbor	B-Protocol
discovery	I-Protocol
optimization	O
,	O
with	O
selective	O
fragment	B-Protocol
recovery	O
and	O
with	O
smaller	O
changes	O
in	O
and	O
)	O
.	O
</s>
<s>
IPv6	B-Protocol
over	O
Bluetooth	B-General_Concept
Low	I-General_Concept
Energy	I-General_Concept
using	O
6LoWPAN	B-Protocol
techniques	O
is	O
described	O
in	O
.	O
</s>
<s>
The	O
targets	O
for	O
IPv6	B-Protocol
networking	O
for	O
low-power	O
radio	O
communication	O
are	O
devices	O
that	O
need	O
wireless	O
connectivity	O
to	O
many	O
other	O
devices	O
at	O
lower	O
data	O
rates	O
for	O
devices	O
with	O
very	O
limited	O
power	O
consumption	O
.	O
</s>
<s>
The	O
header	O
compression	O
mechanisms	O
in	O
are	O
used	O
to	O
allow	O
IPv6	B-Protocol
packets	O
to	O
travel	O
over	O
such	O
networks	O
.	O
</s>
<s>
IPv6	B-Protocol
is	O
also	O
in	O
use	O
on	O
the	O
smart	B-Architecture
grid	I-Architecture
enabling	O
smart	B-Device
meters	I-Device
and	O
other	O
devices	O
to	O
build	O
a	O
micro	O
mesh	B-Architecture
network	I-Architecture
before	O
sending	O
the	O
data	O
back	O
to	O
the	O
billing	O
system	O
using	O
the	O
IPv6	B-Protocol
backbone	O
.	O
</s>
<s>
Thread	B-Protocol
is	O
a	O
standard	O
from	O
a	O
group	O
of	O
more	O
than	O
fifty	O
companies	O
for	O
a	O
protocol	O
running	O
over	O
6LoWPAN	B-Protocol
to	O
enable	O
home	O
automation	O
.	O
</s>
<s>
The	O
protocol	O
will	O
most	O
directly	O
compete	O
with	O
Z-Wave	B-Device
and	O
Zigbee	B-Protocol
IP	O
.	O
</s>
<s>
As	O
with	O
all	O
link-layer	B-Protocol
mappings	O
of	O
IP	O
,	O
RFC4944	O
provides	O
a	O
number	O
of	O
functions	O
.	O
</s>
<s>
Beyond	O
the	O
usual	O
differences	O
between	O
L2	O
and	O
L3	O
networks	O
,	O
mapping	O
from	O
the	O
IPv6	B-Protocol
network	O
to	O
the	O
IEEE	O
802.15.4	O
network	O
poses	O
additional	O
design	O
challenges	O
(	O
see	O
for	O
an	O
overview	O
)	O
.	O
</s>
<s>
IPv6	B-Protocol
requires	O
the	O
link	B-Protocol
maximum	B-Protocol
transmission	I-Protocol
unit	I-Protocol
(	O
MTU	B-Protocol
)	O
to	O
be	O
at	O
least	O
1280	O
octets	O
.	O
</s>
<s>
In	O
contrast	O
,	O
IEEE	O
802.15.4	O
'	O
s	O
standard	O
frame	B-Protocol
size	O
is	O
127	O
octets	O
.	O
</s>
<s>
A	O
maximum	O
frame	B-Protocol
overhead	O
of	O
25	O
octets	O
and	O
an	O
optional	O
but	O
highly	O
recommended	O
security	O
feature	O
at	O
the	O
link	B-Protocol
layer	I-Protocol
poses	O
an	O
additional	O
overhead	O
of	O
up	O
to	O
21	O
octets	O
are	O
for	O
AES-CCM-128	O
.	O
</s>
<s>
Since	O
this	O
is	O
so	O
much	O
less	O
than	O
1280	O
,	O
6LowPAN	B-Protocol
defines	O
a	O
fragmentation	O
and	O
reassembly	O
layer	O
.	O
</s>
<s>
Further	O
,	O
the	O
standard	O
IPv6	B-Protocol
Header	O
is	O
40	O
octets	O
long	O
,	O
so	O
header	O
compression	O
is	O
defined	O
as	O
well	O
.	O
</s>
<s>
IPv6	B-Protocol
nodes	O
are	O
assigned	O
128	O
bit	O
IP	B-Protocol
addresses	I-Protocol
in	O
a	O
hierarchical	O
manner	O
,	O
through	O
an	O
arbitrary	O
length	O
network	O
prefix	O
.	O
</s>
<s>
IPv6	B-Protocol
nodes	O
are	O
geared	O
towards	O
attaining	O
high	O
speeds	O
.	O
</s>
<s>
Algorithms	O
and	O
protocols	O
implemented	O
at	O
the	O
higher	O
layers	O
such	O
as	O
TCP	O
kernel	O
of	O
the	O
TCP/IP	B-Protocol
are	O
optimized	O
to	O
handle	O
typical	O
network	O
problems	O
such	O
as	O
congestion	O
.	O
</s>
<s>
An	O
adaptation	O
mechanism	O
to	O
allow	O
interoperability	O
between	O
IPv6	B-Protocol
domain	O
and	O
the	O
IEEE	O
802.15.4	O
can	O
best	O
be	O
viewed	O
as	O
a	O
layer	O
problem	O
.	O
</s>
<s>
proposes	O
an	O
adaptation	O
layer	O
to	O
allow	O
the	O
transmission	O
of	O
IPv6	B-Protocol
datagrams	O
over	O
IEEE	O
802.15.4	O
networks	O
.	O
</s>
<s>
The	O
management	O
of	O
addresses	O
for	O
devices	O
that	O
communicate	O
across	O
the	O
two	O
dissimilar	O
domains	O
of	O
IPv6	B-Protocol
and	O
IEEE	O
802.15.4	O
is	O
cumbersome	O
,	O
if	O
not	O
exhaustingly	O
complex	O
.	O
</s>
<s>
Mesh	B-Architecture
routing	I-Architecture
in	O
the	O
personal	B-General_Concept
area	I-General_Concept
network	I-General_Concept
(	O
PAN	O
)	O
space	O
.	O
</s>
<s>
The	O
routability	O
of	O
packets	O
between	O
the	O
IPv6	B-Protocol
domain	O
and	O
the	O
PAN	O
domain	O
.	O
</s>
<s>
Several	O
routing	O
protocols	O
have	O
been	O
proposed	O
by	O
the	O
6LoWPAN	B-Protocol
community	O
such	O
as	O
LOAD	O
,	O
DYMO-LOW	O
,	O
HI-LOW	O
.	O
</s>
<s>
Since	O
IP-enabled	O
devices	O
may	O
require	O
the	O
formation	O
of	O
ad	B-Protocol
hoc	I-Protocol
networks	I-Protocol
,	O
the	O
current	O
state	O
of	O
neighboring	O
devices	O
and	O
the	O
services	O
hosted	O
by	O
such	O
devices	O
will	O
need	O
to	O
be	O
known	O
.	O
</s>
<s>
IPv6	B-Protocol
neighbour	O
discovery	O
extensions	O
is	O
an	O
internet	O
draft	O
proposed	O
as	O
a	O
contribution	O
in	O
this	O
area	O
.	O
</s>
