<s>
Network	B-Architecture
mapping	I-Architecture
is	O
the	O
study	O
of	O
the	O
physical	O
connectivity	O
of	O
networks	O
e.g.	O
</s>
<s>
Network	B-Architecture
mapping	I-Architecture
discovers	O
the	O
devices	O
on	O
the	O
network	O
and	O
their	O
connectivity	O
.	O
</s>
<s>
It	B-General_Concept
is	O
not	O
to	O
be	O
confused	O
with	O
network	O
discovery	O
or	O
network	B-General_Concept
enumerating	I-General_Concept
which	O
discovers	O
devices	O
on	O
the	O
network	O
and	O
their	O
characteristics	O
such	O
as	O
(	O
operating	B-General_Concept
system	I-General_Concept
,	O
open	O
ports	B-Protocol
,	O
listening	O
network	B-General_Concept
services	I-General_Concept
,	O
etc	O
.	O
)	O
.	O
</s>
<s>
The	O
field	O
of	O
automated	O
network	B-Architecture
mapping	I-Architecture
has	O
taken	O
on	O
greater	O
importance	O
as	O
networks	O
become	O
more	O
dynamic	O
and	O
complex	O
in	O
nature	O
.	O
</s>
<s>
Images	O
of	O
some	O
of	O
the	O
first	O
attempts	O
at	O
a	O
large	O
scale	O
map	O
of	O
the	O
internet	O
were	O
produced	O
by	O
the	O
Internet	B-Architecture
Mapping	I-Architecture
Project	I-Architecture
and	O
appeared	O
in	O
Wired	O
magazine	O
.	O
</s>
<s>
The	O
maps	O
produced	O
by	O
this	O
project	O
were	O
based	O
on	O
the	O
layer	B-Application
3	I-Application
or	O
IP	B-Protocol
level	O
connectivity	O
of	O
the	O
Internet	O
(	O
see	O
OSI	O
model	O
)	O
,	O
but	O
there	O
are	O
different	O
aspects	O
of	O
internet	O
structure	O
that	O
have	O
also	O
been	O
mapped	O
.	O
</s>
<s>
An	O
example	O
of	O
such	O
an	O
effort	O
is	O
the	B-Application
OPTE	I-Application
project	I-Application
,	O
which	O
is	O
attempting	O
to	O
develop	O
a	O
system	O
capable	O
of	O
mapping	O
the	O
internet	O
in	O
a	O
single	O
day	O
.	O
</s>
<s>
The	O
"	O
Map	O
of	O
the	O
Internet	O
Project	O
"	O
maps	O
over	O
4	O
billion	O
internet	O
locations	O
as	O
cubes	O
in	O
3D	O
cyberspace	B-General_Concept
.	O
</s>
<s>
In	O
early	O
2011	O
Canadian	O
based	O
ISP	O
PEER	B-General_Concept
1	I-General_Concept
Hosting	I-General_Concept
created	O
their	O
own	O
Map	O
of	O
the	O
Internet	O
that	O
depicts	O
a	O
graph	O
of	O
19,869	O
autonomous	B-Architecture
system	I-Architecture
nodes	O
connected	O
by	O
44,344	O
connections	O
.	O
</s>
<s>
The	O
sizing	O
and	O
layout	O
of	O
the	O
autonomous	B-Architecture
systems	I-Architecture
was	O
calculated	O
based	O
on	O
their	O
eigenvector	O
centrality	O
,	O
which	O
is	O
a	O
measure	O
of	O
how	O
central	O
to	O
the	O
network	O
each	O
autonomous	B-Architecture
system	I-Architecture
is	O
.	O
</s>
<s>
Graph	O
theory	O
can	O
be	O
used	O
to	O
better	O
understand	O
maps	O
of	O
the	O
internet	O
and	O
to	O
help	O
choose	O
between	O
the	O
many	O
ways	O
to	O
visualize	B-Application
internet	B-Architecture
maps	I-Architecture
.	O
</s>
<s>
Some	O
projects	O
have	O
attempted	O
to	O
incorporate	O
geographical	O
data	O
into	O
their	O
internet	B-Architecture
maps	I-Architecture
(	O
for	O
example	O
,	O
to	O
draw	O
locations	O
of	O
routers	B-Protocol
and	O
nodes	O
on	O
a	O
map	O
of	O
the	O
world	O
)	O
,	O
but	O
others	O
are	O
only	O
concerned	O
with	O
representing	O
the	O
more	O
abstract	O
structures	O
of	O
the	O
internet	O
,	O
such	O
as	O
the	O
allocation	O
,	O
structure	O
,	O
and	O
purpose	O
of	O
IP	B-Protocol
space	I-Protocol
.	O
</s>
<s>
Many	O
organizations	O
create	O
network	B-Architecture
maps	I-Architecture
of	O
their	O
network	O
system	O
.	O
</s>
<s>
These	O
maps	O
can	O
be	O
made	O
manually	O
using	O
simple	O
tools	O
such	O
as	O
Microsoft	B-Application
Visio	I-Application
,	O
or	O
the	O
mapping	O
process	O
can	O
be	O
simplified	O
by	O
using	O
tools	O
that	O
integrate	O
auto	O
network	O
discovery	O
with	O
Network	B-Architecture
mapping	I-Architecture
,	O
one	O
such	O
example	O
being	O
the	O
Fabric	O
platform	O
.	O
</s>
<s>
Many	O
of	O
the	O
vendors	O
from	O
the	O
Notable	O
network	B-Architecture
mappers	I-Architecture
list	O
enable	O
you	O
to	O
customize	O
the	O
maps	O
and	O
include	O
your	O
own	O
labels	O
,	O
add	O
un-discoverable	O
items	O
and	O
background	O
images	O
.	O
</s>
<s>
Sophisticated	O
mapping	O
is	O
used	O
to	O
help	O
visualize	B-Application
the	O
network	O
and	O
understand	O
relationships	O
between	O
end	O
devices	O
and	O
the	O
transport	O
layers	O
that	O
provide	O
service	O
.	O
</s>
<s>
Mostly	O
,	O
network	B-General_Concept
scanners	I-General_Concept
detect	O
the	O
network	O
with	O
all	O
its	O
components	O
and	O
deliver	O
a	O
list	O
which	O
is	O
used	O
for	O
creating	O
charts	O
and	O
maps	O
using	O
network	B-Architecture
mapping	I-Architecture
software	O
.	O
</s>
<s>
There	O
are	O
three	O
main	O
techniques	O
used	O
for	O
network	B-Architecture
mapping	I-Architecture
:	O
SNMP	B-Protocol
based	O
approaches	O
,	O
active	O
probing	O
and	O
route	O
analytics	O
.	O
</s>
<s>
The	O
SNMP	B-Protocol
based	O
approach	O
retrieves	O
data	O
from	O
Router	B-Protocol
and	O
Switch	O
MIBs	O
in	O
order	O
to	O
build	O
the	O
network	B-Architecture
map	I-Architecture
.	O
</s>
<s>
The	O
active	O
probing	O
approach	O
relies	O
on	O
a	O
series	O
of	O
traceroute-like	O
probe	O
packets	O
in	O
order	O
to	O
build	O
the	O
network	B-Architecture
map	I-Architecture
.	O
</s>
<s>
The	O
route	O
analytics	O
approach	O
relies	O
on	O
information	O
from	O
the	O
routing	B-Protocol
protocols	I-Protocol
to	O
build	O
the	O
network	B-Architecture
map	I-Architecture
.	O
</s>
<s>
There	O
are	O
two	O
prominent	O
techniques	O
used	O
today	O
to	O
create	O
Internet	B-Architecture
maps	I-Architecture
.	O
</s>
<s>
It	B-General_Concept
is	O
used	O
to	O
infer	O
Internet	B-Architecture
topology	I-Architecture
based	O
on	O
router	B-Protocol
adjacencies	O
.	O
</s>
<s>
The	O
second	O
works	O
on	O
the	O
control	O
plane	O
and	O
infers	O
autonomous	B-Architecture
system	I-Architecture
connectivity	O
based	O
on	O
BGP	B-Protocol
data	O
.	O
</s>
<s>
A	O
BGP	B-Protocol
speaker	O
sends	O
19-byte	O
keep-alive	O
messages	O
every	O
60	O
seconds	O
to	O
maintain	O
the	O
connection	O
.	O
</s>
<s>
This	O
technique	O
relies	O
on	O
traceroute-like	O
probing	O
on	O
the	O
IP	B-Protocol
address	O
space	O
.	O
</s>
<s>
These	O
probes	O
report	O
back	O
IP	B-Protocol
forwarding	O
paths	O
to	O
the	O
destination	O
address	O
.	O
</s>
<s>
By	O
combining	O
these	O
paths	O
one	O
can	O
infer	O
router	B-Protocol
level	O
topology	B-Architecture
for	O
a	O
given	O
POP	O
.	O
</s>
<s>
It	B-General_Concept
is	O
also	O
more	O
likely	O
to	O
find	O
peering	B-Protocol
links	O
between	O
ISPs	O
.	O
</s>
<s>
It	B-General_Concept
is	O
more	O
likely	O
to	O
infer	O
false	O
topologies	B-Architecture
due	O
to	O
load	O
balancing	O
routers	B-Protocol
and	O
routers	B-Protocol
with	O
multiple	O
IP	B-Protocol
address	O
aliases	O
.	O
</s>
<s>
Decreased	O
global	O
support	O
for	O
enhanced	O
probing	O
mechanisms	O
such	O
as	O
source-route	O
probing	O
,	O
ICMP	B-Protocol
Echo	O
Broadcasting	O
,	O
and	O
IP	B-Protocol
Address	O
Resolution	O
techniques	O
leaves	O
this	O
type	O
of	O
probing	O
in	O
the	O
realm	O
of	O
network	O
diagnosis	O
.	O
</s>
<s>
This	O
technique	O
relies	O
on	O
various	O
BGP	B-Protocol
collectors	O
who	O
collect	O
routing	O
updates	O
and	O
tables	O
and	O
provide	O
this	O
information	O
publicly	O
.	O
</s>
<s>
Each	O
BGP	B-Protocol
entry	O
contains	O
a	O
Path	B-Protocol
Vector	I-Protocol
attribute	O
called	O
the	O
AS	O
Path	O
.	O
</s>
<s>
This	O
path	O
represents	O
an	O
autonomous	B-Architecture
system	I-Architecture
forwarding	O
path	O
from	O
a	O
given	O
origin	O
for	O
a	O
given	O
set	O
of	O
prefixes	O
.	O
</s>
<s>
These	O
paths	O
can	O
be	O
used	O
to	O
infer	O
AS-level	O
connectivity	O
and	O
in	O
turn	O
be	O
used	O
to	O
build	O
AS	O
topology	B-Architecture
graphs	O
.	O
</s>
<s>
A	O
single	O
AS	O
link	O
can	O
in	O
reality	O
be	O
several	O
router	B-Protocol
links	O
.	O
</s>
<s>
It	B-General_Concept
is	O
also	O
much	O
harder	O
to	O
infer	O
peerings	B-Protocol
between	O
two	O
AS	O
nodes	O
as	O
these	O
peering	B-Protocol
relationships	O
are	O
only	O
propagated	O
to	O
an	O
ISP	O
's	O
customer	O
networks	O
.	O
</s>
<s>
New	O
toolsets	O
are	O
emerging	O
such	O
as	O
Cyclops	O
and	O
NetViews	O
that	O
take	O
advantage	O
of	O
a	O
new	O
experimental	O
BGP	B-Protocol
collector	O
BGPMon	O
.	O
</s>
<s>
NetViews	O
can	O
not	O
only	O
build	O
topology	B-Architecture
maps	O
in	O
seconds	O
but	O
visualize	B-Application
topology	B-Architecture
changes	O
moments	O
after	O
occurring	O
at	O
the	O
actual	O
router	B-Protocol
.	O
</s>
<s>
In	O
comparison	O
to	O
what	O
the	O
tools	O
using	O
BGPMon	O
does	O
there	O
is	O
another	O
tool	O
netTransformer	O
able	O
to	O
discover	O
and	O
generate	O
BGP	B-Protocol
peering	B-Protocol
maps	O
either	O
through	O
SNMP	B-Protocol
polling	O
or	O
by	O
converting	O
MRT	O
dumps	O
to	O
a	O
graphml	B-Language
file	O
format	O
.	O
</s>
<s>
netTransformer	O
allows	O
us	O
also	O
to	O
perform	O
network	O
diffs	O
between	O
any	O
two	O
dumps	O
and	O
thus	O
to	O
reason	O
how	O
does	O
the	O
BGP	B-Protocol
peering	B-Protocol
has	O
evolved	O
through	O
the	O
years	O
.	O
</s>
<s>
WhatsUp	O
Gold	O
,	O
an	O
IT	B-General_Concept
monitoring	O
tool	O
,	O
tracks	O
networks	O
,	O
servers	O
,	O
applications	O
,	O
storage	O
devices	O
,	O
virtual	O
devices	O
and	O
incorporates	O
infrastructure	O
management	O
,	O
application	O
performance	O
management	O
.	O
</s>
