<s>
The	O
content-addressable	B-Protocol
network	I-Protocol
(	O
CAN	O
)	O
is	O
a	O
distributed	O
,	O
decentralized	O
P2P	O
infrastructure	O
that	O
provides	O
hash	B-Algorithm
table	I-Algorithm
functionality	O
on	O
an	O
Internet-like	O
scale	O
.	O
</s>
<s>
CAN	O
was	O
one	O
of	O
the	O
original	O
four	O
distributed	B-Operating_System
hash	I-Operating_System
table	I-Operating_System
proposals	O
,	O
introduced	O
concurrently	O
with	O
Chord	B-Application
,	O
Pastry	O
,	O
and	O
Tapestry	O
.	O
</s>
<s>
Like	O
other	O
distributed	B-Operating_System
hash	I-Operating_System
tables	I-Operating_System
,	O
CAN	O
is	O
designed	O
to	O
be	O
scalable	B-Architecture
,	O
fault	B-General_Concept
tolerant	I-General_Concept
,	O
and	O
self-organizing	O
.	O
</s>
<s>
The	O
architectural	O
design	O
is	O
a	O
virtual	B-Application
multi-dimensional	O
Cartesian	O
coordinate	O
space	O
,	O
a	O
type	O
of	O
overlay	B-Architecture
network	I-Architecture
,	O
on	O
a	O
multi-torus	O
.	O
</s>
<s>
This	O
n-dimensional	O
coordinate	O
space	O
is	O
a	O
virtual	B-Application
logical	B-General_Concept
address	I-General_Concept
,	O
completely	O
independent	O
of	O
the	O
physical	O
location	O
and	O
physical	O
connectivity	O
of	O
the	O
nodes	O
.	O
</s>
<s>
A	O
CAN	O
node	O
maintains	O
a	O
routing	B-Protocol
table	I-Protocol
that	O
holds	O
the	O
IP	B-Protocol
address	I-Protocol
and	O
virtual	B-Application
coordinate	O
zone	O
of	O
each	O
of	O
its	O
neighbors	O
.	O
</s>
<s>
The	O
node	O
first	O
determines	O
which	O
neighboring	O
zone	O
is	O
closest	O
to	O
the	O
destination	O
point	O
,	O
and	O
then	O
looks	O
up	O
that	O
zone	O
's	O
node	O
's	O
IP	B-Protocol
address	I-Protocol
via	O
the	O
routing	B-Protocol
table	I-Protocol
.	O
</s>
<s>
Find	O
a	O
node	O
already	O
in	O
the	O
overlay	B-Architecture
network	I-Architecture
.	O
</s>
<s>
Update	O
the	O
routing	B-Protocol
tables	I-Protocol
of	O
nodes	O
neighboring	O
the	O
newly	O
split	O
zone	O
.	O
</s>
<s>
To	O
find	O
a	O
node	O
already	O
in	O
the	O
overlay	B-Architecture
network	I-Architecture
,	O
bootstrapping	O
nodes	O
may	O
be	O
used	O
to	O
inform	O
the	O
joining	O
node	O
of	O
IP	B-Protocol
addresses	I-Protocol
of	O
nodes	O
currently	O
in	O
the	O
overlay	B-Architecture
network	I-Architecture
.	O
</s>
<s>
After	O
the	O
joining	O
node	O
receives	O
an	O
IP	B-Protocol
address	I-Protocol
of	O
a	O
node	O
already	O
in	O
the	O
CAN	O
,	O
it	O
can	O
attempt	O
to	O
identify	O
a	O
zone	O
for	O
itself	O
.	O
</s>
<s>
The	O
joining	O
node	O
randomly	O
picks	O
a	O
point	O
in	O
the	O
coordinate	O
space	O
and	O
sends	O
a	O
join	O
request	O
,	O
directed	O
to	O
the	O
random	O
point	O
,	O
to	O
one	O
of	O
the	O
received	O
IP	B-Protocol
addresses	I-Protocol
.	O
</s>
<s>
The	O
nodes	O
already	O
in	O
the	O
overlay	B-Architecture
network	I-Architecture
route	O
the	O
join	O
request	O
to	O
the	O
correct	O
device	O
via	O
their	O
zone-to-IP	O
routing	B-Protocol
tables	I-Protocol
.	O
</s>
<s>
After	O
the	O
zone	O
split	O
and	O
allocation	O
is	O
complete	O
,	O
the	O
neighboring	O
nodes	O
are	O
updated	O
with	O
the	O
coordinates	O
of	O
the	O
two	O
new	O
zones	O
and	O
the	O
corresponding	O
IP	B-Protocol
addresses	I-Protocol
.	O
</s>
<s>
Routing	B-Protocol
tables	I-Protocol
are	O
updated	O
and	O
updates	O
are	O
propagated	O
across	O
the	O
network	O
.	O
</s>
<s>
update	O
the	O
routing	B-Protocol
tables	I-Protocol
across	O
the	O
network	O
.	O
</s>
<s>
Detecting	O
a	O
node	O
's	O
departure	O
can	O
be	O
done	O
,	O
for	O
instance	O
,	O
via	O
heartbeat	O
messages	O
that	O
periodically	O
broadcast	O
routing	B-Protocol
table	I-Protocol
information	O
between	O
neighbors	O
.	O
</s>
<s>
If	O
the	O
merge	O
is	O
successful	O
,	O
routing	B-Protocol
tables	I-Protocol
of	O
neighboring	O
zones	O
 '	O
nodes	O
are	O
updated	O
to	O
reflect	O
the	O
merge	O
.	O
</s>
<s>
The	O
network	O
will	O
see	O
the	O
subsection	O
of	O
the	O
overlay	B-Architecture
network	I-Architecture
as	O
one	O
,	O
single	O
zone	O
after	O
a	O
merge	O
and	O
treat	O
all	O
routing	O
processing	O
with	O
this	O
mindset	O
.	O
</s>
<s>
To	O
effectuate	O
a	O
take-over	O
,	O
the	O
take-over	O
node	O
updates	O
neighboring	O
zones	O
 '	O
nodes	O
 '	O
routing	B-Protocol
tables	I-Protocol
,	O
so	O
that	O
requests	O
to	O
either	O
zone	O
resolve	O
to	O
the	O
take-over	O
node	O
.	O
</s>
<s>
And	O
,	O
as	O
such	O
,	O
the	O
network	O
still	O
sees	O
the	O
subsection	O
of	O
the	O
overlay	B-Architecture
network	I-Architecture
as	O
two	O
separate	O
zones	O
and	O
treats	O
all	O
routing	O
processing	O
with	O
this	O
mindset	O
.	O
</s>
