<s>
Link	B-Protocol
Layer	I-Protocol
Topology	I-Protocol
Discovery	I-Protocol
(	O
LLTD	B-Protocol
)	O
is	O
a	O
proprietary	O
link	B-Protocol
layer	I-Protocol
protocol	O
for	O
network	B-Architecture
topology	I-Architecture
discovery	O
and	O
quality	O
of	O
service	O
diagnostics	O
.	O
</s>
<s>
Microsoft	O
developed	O
it	O
as	O
part	O
of	O
the	O
Windows	B-Library
Rally	I-Library
set	O
of	O
technologies	O
.	O
</s>
<s>
The	O
LLTD	B-Protocol
protocol	O
operates	O
over	O
both	O
wired	O
(	O
such	O
as	O
Ethernet	O
(	O
IEEE	O
802.3	O
)	O
or	O
power	B-Device
line	I-Device
communication	I-Device
)	O
as	O
well	O
as	O
wireless	O
networks	O
(	O
such	O
as	O
IEEE	O
802.11	O
)	O
.	O
</s>
<s>
LLTD	B-Protocol
is	O
included	O
in	O
Windows	B-Device
7	I-Device
,	O
Windows	B-Application
Vista	I-Application
and	O
Windows	B-Operating_System
10	I-Operating_System
.	O
</s>
<s>
It	O
is	O
used	O
by	O
their	O
Network	O
Map	O
feature	O
to	O
display	O
a	O
graphical	O
representation	O
of	O
the	O
local	B-General_Concept
area	I-General_Concept
network	I-General_Concept
(	O
LAN	B-General_Concept
)	O
or	O
wireless	B-Architecture
LAN	I-Architecture
(	O
WLAN	B-Architecture
)	O
,	O
to	O
which	O
the	O
computer	O
is	O
connected	O
.	O
</s>
<s>
Windows	B-Application
XP	I-Application
does	O
not	O
contain	O
the	O
LLTD	B-Protocol
protocol	O
as	O
a	O
standard	O
component	O
and	O
as	O
a	O
result	O
,	O
Windows	B-Application
XP	I-Application
computers	O
do	O
not	O
appear	O
on	O
the	O
Network	O
Map	O
unless	O
the	O
LLTD	B-Protocol
responder	O
is	O
installed	O
on	O
Windows	B-Application
XP	I-Application
computers	O
.	O
</s>
<s>
LLTD	B-Protocol
is	O
available	O
for	O
download	O
for	O
32-bit	O
editions	O
of	O
Windows	B-Application
XP	I-Application
with	O
Service	O
Pack	O
2	O
(	O
as	O
a	O
publicly	O
released	O
update	O
)	O
and	O
for	O
Windows	B-Application
XP	I-Application
with	O
Service	O
Pack	O
3	O
(	O
as	O
a	O
hotfix	O
by	O
request	O
)	O
.	O
</s>
<s>
LLTD	B-Protocol
Responder	O
was	O
not	O
released	O
for	O
Windows	B-Operating_System
XP	I-Operating_System
Professional	I-Operating_System
x64	I-Operating_System
Edition	I-Operating_System
.	O
</s>
<s>
A	O
2006	O
fall	O
update	O
for	O
the	B-Operating_System
Xbox	I-Operating_System
360	I-Operating_System
enabled	O
support	O
for	O
the	O
LLTD	B-Protocol
protocol	O
.	O
</s>
<s>
Being	O
a	O
link	B-Protocol
layer	I-Protocol
(	O
or	O
OSI	O
Layer	O
2	O
)	O
implementation	O
,	O
LLTD	B-Protocol
operates	O
strictly	O
on	O
a	O
given	O
local	B-General_Concept
network	I-General_Concept
segment	O
.	O
</s>
<s>
It	O
cannot	O
discover	O
devices	O
across	O
routers	B-Protocol
,	O
an	O
operation	O
which	O
would	O
require	O
Internet	B-Protocol
Protocol	I-Protocol
level	O
routing	O
.	O
</s>
<s>
Link	B-Protocol
Layer	I-Protocol
Topology	I-Protocol
Discovery	I-Protocol
in	O
Windows	B-Application
Vista	I-Application
consists	O
of	O
two	O
components	O
.	O
</s>
<s>
The	O
LLTD	B-Protocol
Mapper	O
I/O	O
component	O
is	O
the	O
master	O
module	O
which	O
controls	O
the	O
discovery	O
process	O
and	O
generates	O
the	O
Network	O
Map	O
.	O
</s>
<s>
The	O
Mapper	O
sends	O
discovery	O
command	O
packets	O
onto	O
the	O
local	B-General_Concept
network	I-General_Concept
segment	O
via	O
a	O
raw	O
network	O
interface	O
socket	O
.	O
</s>
<s>
The	O
second	O
component	O
of	O
LLTD	B-Protocol
are	O
the	O
LLTD	B-Protocol
Responders	O
which	O
answer	O
Mapper	O
requests	O
about	O
their	O
host	O
and	O
possibly	O
other	O
discovered	O
network	O
information	O
.	O
</s>
<s>
In	O
addition	O
to	O
illustrating	O
the	O
layout	O
of	O
a	O
network	O
with	O
representative	O
icons	O
for	O
the	O
hosts	O
and	O
interconnecting	O
lines	O
,	O
each	O
device	O
icon	O
may	O
be	O
explored	O
to	O
produce	O
a	O
popup	O
information	O
box	O
summarizing	O
important	O
network	O
and	O
host	O
parameters	O
,	O
such	O
as	O
MAC	O
address	O
and	O
IP	B-Protocol
address	I-Protocol
(	O
both	O
IPv4	B-Protocol
and	O
IPv6	B-Protocol
)	O
.	O
</s>
<s>
Icons	O
are	O
labeled	O
with	O
the	O
hostnames	O
(	O
or	O
first	O
component	O
of	O
their	O
fully	B-Protocol
qualified	I-Protocol
domain	I-Protocol
names	I-Protocol
)	O
,	O
or	O
a	O
representative	O
name	O
of	O
the	O
function	O
of	O
the	O
device	O
,	O
e.g.	O
,	O
"	O
gateway	O
"	O
.	O
</s>
<s>
The	O
LLTD	B-Protocol
responder	O
for	O
Windows	B-Application
XP	I-Application
only	O
supports	O
reporting	O
of	O
IPv4	B-Protocol
addresses	O
and	O
not	O
IPv6	B-Protocol
.	O
</s>
<s>
A	O
royalty	O
free	O
Linux	B-Application
sample	O
implementation	O
of	O
the	O
LLTD	B-Protocol
responder	O
is	O
available	O
from	O
Microsoft	O
as	O
part	O
of	O
the	O
Windows	B-Library
Rally	I-Library
Development	O
Kit	O
.	O
</s>
<s>
Using	O
LLTD	B-Protocol
specifications	O
requires	O
signing	O
a	O
Microsoft	O
Windows	B-Library
Rally	I-Library
license	O
agreement	O
.	O
</s>
<s>
There	O
also	O
exists	O
a	O
Perl	B-Language
implementation	O
,	O
using	O
Net::Frame	O
,	O
available	O
via	O
CPAN	B-Language
.	O
</s>
