<s>
Locator/ID	O
Separation	O
Protocol	O
(	O
LISP	O
)	O
(	O
)	O
is	O
a	O
"	O
map-and-encapsulate	O
"	O
protocol	O
which	O
is	O
developed	O
by	O
the	O
Internet	O
Engineering	O
Task	O
Force	O
LISP	O
Working	O
Group	O
.	O
</s>
<s>
The	O
basic	O
idea	O
behind	O
the	O
separation	O
is	O
that	O
the	O
Internet	O
architecture	O
combines	O
two	O
functions	O
,	O
routing	B-Protocol
locators	O
(	O
where	O
a	O
client	O
is	O
attached	O
to	O
the	O
network	O
)	O
and	O
identifiers	O
(	O
who	O
the	O
client	O
is	O
)	O
in	O
one	O
number	O
space	O
:	O
the	O
IP	B-Protocol
address	I-Protocol
.	O
</s>
<s>
In	O
LISP	O
,	O
both	O
identifiers	O
and	O
locators	O
can	O
be	O
IP	B-Protocol
addresses	I-Protocol
or	O
arbitrary	O
elements	O
like	O
a	O
set	O
of	O
GPS	O
coordinates	O
or	O
a	O
MAC	O
address	O
.	O
</s>
<s>
The	O
Internet	O
Architecture	O
Board	O
's	O
October	O
2006	O
Routing	B-Protocol
and	O
Addressing	O
Workshop	O
renewed	O
interest	O
in	O
the	O
design	O
of	O
a	O
scalable	O
routing	B-Protocol
and	O
addressing	O
architecture	O
for	O
the	O
Internet	O
.	O
</s>
<s>
Key	O
issues	O
driving	O
this	O
renewed	O
interest	O
include	O
concerns	O
about	O
the	O
scalability	O
of	O
the	O
routing	B-Protocol
system	O
and	O
the	O
impending	O
exhaustion	O
of	O
IPv4	O
address	O
space	O
.	O
</s>
<s>
All	O
of	O
these	O
proposals	O
are	O
based	O
on	O
a	O
common	O
concept	O
:	O
the	O
separation	O
of	O
Locator	B-General_Concept
and	O
Identifier	O
in	O
the	O
numbering	O
of	O
Internet	O
devices	O
,	O
often	O
termed	O
the	O
"	O
Loc/ID	O
split	O
"	O
.	O
</s>
<s>
The	O
current	O
namespace	O
architecture	O
used	O
by	O
the	O
Internet	B-Protocol
Protocol	I-Protocol
uses	O
IP	B-Protocol
addresses	I-Protocol
for	O
two	O
separate	O
functions	O
:	O
</s>
<s>
Routing	B-Protocol
Locator	B-General_Concept
(	O
RLOC	O
)	O
:	O
A	O
RLOC	O
is	O
an	O
IPv4	O
or	O
IPv6	O
address	O
of	O
an	O
egress	O
tunnel	O
router	B-Protocol
(	O
ETR	O
)	O
.	O
</s>
<s>
Egress	O
Tunnel	O
Router	B-Protocol
(	O
ETR	O
)	O
:	O
An	O
ETR	O
is	O
a	O
device	O
that	O
is	O
the	O
tunnel	O
endpoint	O
;	O
it	O
accepts	O
an	O
IP	O
packet	O
where	O
the	O
destination	O
address	O
in	O
the	O
"	O
outer	O
"	O
IP	O
header	O
is	O
one	O
of	O
its	O
own	O
RLOCs	O
.	O
</s>
<s>
ETR	O
functionality	O
does	O
not	O
have	O
to	O
be	O
limited	O
to	O
a	O
router	B-Protocol
device	O
;	O
server	O
host	O
can	O
be	O
the	O
endpoint	O
of	O
a	O
LISP	O
tunnel	O
as	O
well	O
.	O
</s>
<s>
Ingress	O
Tunnel	O
Router	B-Protocol
(	O
ITR	O
)	O
:	O
An	O
ITR	O
is	O
a	O
device	O
that	O
is	O
the	O
tunnel	O
start	O
point	O
;	O
it	O
receives	O
IP	O
packets	O
from	O
site	O
end-systems	O
on	O
one	O
side	O
and	O
sends	O
LISP-encapsulated	O
IP	O
packets	O
,	O
across	O
the	O
Internet	O
to	O
an	O
ETR	O
,	O
on	O
the	O
other	O
side	O
.	O
</s>
<s>
Re-encapsulating	O
Tunnel	O
Router	B-Protocol
(	O
RTR	O
)	O
:	O
An	O
RTR	O
is	O
used	O
for	O
connecting	O
LISP-to-LISP	O
communications	O
within	O
environments	O
where	O
direct	O
connectivity	O
is	O
not	O
supported	O
.	O
</s>
<s>
Examples	O
include	O
:	O
1	O
)	O
joining	O
LISP	O
sites	O
connected	O
to	O
"	O
disjointed	O
locator	B-General_Concept
spaces	O
"	O
—	O
for	O
example	O
a	O
LISP	O
site	O
with	O
IPv4-only	O
RLOC	O
connectivity	O
and	O
a	O
LISP	O
site	O
with	O
IPv6-only	O
RLOC	O
connectivity	O
;	O
and	O
2	O
)	O
creating	O
a	O
data	O
plane	O
'	O
anchor	O
point	O
 '	O
by	O
a	O
LISP-speaking	O
device	O
behind	O
a	O
NAT	B-Protocol
box	I-Protocol
to	O
send	O
and	O
receive	O
traffic	O
through	O
the	O
NAT	B-Protocol
device	I-Protocol
.	O
</s>
<s>
In	O
the	O
Locator/Identifier	B-Protocol
Separation	I-Protocol
Protocol	I-Protocol
the	O
network	O
elements	O
(	O
routers	B-Protocol
)	O
are	O
responsible	O
for	O
looking	O
up	O
the	O
mapping	O
between	O
end-point-identifiers	O
(	O
EID	O
)	O
and	O
route	O
locators	O
(	O
RLOC	O
)	O
and	O
this	O
process	O
is	O
invisible	O
to	O
the	O
Internet	O
end-hosts	O
.	O
</s>
<s>
The	O
LISP	O
beta	O
network	O
initially	O
used	O
a	O
BGP-based	O
mapping	O
system	O
called	O
LISP	O
ALternative	O
Topology	O
(	O
LISP+ALT	O
)	O
,	O
but	O
this	O
has	O
now	O
been	O
replaced	O
by	O
a	O
DNS-like	O
indexing	O
system	O
called	O
DDT	O
inspired	O
from	O
LISP-TREE	O
.	O
</s>
<s>
Cisco	O
has	O
released	O
public	O
IOS	B-Protocol
,	O
IOS	B-Device
XR	I-Device
,	O
IOS	B-Device
XE	I-Device
and	O
NX-OS	B-Operating_System
images	O
which	O
support	O
LISP	O
.	O
</s>
<s>
A	O
team	O
of	O
researchers	O
from	O
the	O
Université	O
catholique	O
de	O
Louvain	O
and	O
T-Labs/TU	O
Berlin	O
have	O
written	O
a	O
FreeBSD	B-Operating_System
implementation	O
called	O
OpenLISP	O
.	O
</s>
<s>
Historically	O
,	O
LISPmob	O
was	O
an	O
open	O
source	O
implementation	O
of	O
LISP	O
for	O
Linux	B-Application
,	O
OpenWRT	B-Application
and	O
Android	B-Application
maintained	O
at	O
Polytechnic	O
University	O
of	O
Catalonia	O
.	O
</s>
<s>
Recently	O
,	O
this	O
implementation	O
has	O
been	O
further	O
developed	O
into	O
a	O
full	O
open	O
source	O
LISP	O
router	B-Protocol
called	O
the	O
"	O
Open	O
Overlay	O
Router	B-Protocol
"	O
or	O
OOR	O
.	O
</s>
<s>
AVM	O
added	O
LISP	O
support	O
in	O
firmware	O
for	O
their	O
FRITZ	B-Application
!	I-Application
Box	I-Application
devices	O
starring	O
from	O
FRITZ	B-Application
!	I-Application
OS	I-Application
version	O
6.00	O
.	O
</s>
<s>
HPE	O
supports	O
LISP	O
in	O
their	O
Comware	O
7	O
platform	O
based	O
routers	B-Protocol
(	O
under	O
the	O
marketing	O
name	O
FlexNetwork	O
MSR	O
and	O
VSR	O
)	O
.	O
</s>
<s>
OpenDaylight	B-Application
supports	O
LISP	O
flow	O
mappings	O
.	O
</s>
<s>
ONOS	B-Application
develops	O
a	O
distributed	O
LISP	O
control	O
plane	O
as	O
an	O
SDN	O
application	O
.	O
</s>
<s>
Participants	O
include	O
Google	B-Application
,	O
Facebook	B-Application
,	O
NTT	O
,	O
Level3	O
,	O
InTouch	O
N.V.	O
and	O
the	O
Internet	O
Systems	O
Consortium	O
.	O
</s>
<s>
The	O
geographical	O
distribution	O
of	O
participating	O
routers	B-Protocol
,	O
and	O
the	O
prefixes	O
they	O
are	O
responsible	O
for	O
,	O
can	O
be	O
observed	O
on	O
the	O
project	O
website	O
(	O
updated	O
daily	O
)	O
.	O
</s>
<s>
The	O
LISP-Lab	O
project	O
,	O
coordinated	O
by	O
UPMC/LIP6	O
,	O
aims	O
at	O
building	O
a	O
LISP	O
network	O
experimentation	O
platform	O
exclusively	O
built	O
using	O
open	O
source	O
LISP	O
nodes	O
(	O
OpenLISP	O
)	O
acting	O
as	O
ITR/ETR	O
tunnelling	O
routers	B-Protocol
,	O
MS/MR	O
mapping	O
servers/resolvers	O
,	O
DDT	O
root	O
and	O
Proxy	O
ITR/ETR	O
.	O
</s>
<s>
Several	O
proposals	O
for	O
separating	O
the	O
two	O
functions	O
and	O
allowing	O
the	O
Internet	O
to	O
scale	O
better	O
have	O
been	O
proposed	O
,	O
for	O
instance	O
GSE/8	O
+8	O
as	O
network	O
based	O
solution	O
and	O
SHIM6	B-Protocol
,	O
HIP	B-Protocol
and	O
ILNP	B-Protocol
as	O
host	O
based	O
solutions	O
.	O
</s>
