<s>
On-Demand	O
Routing	O
(	O
"	O
ODR	O
"	O
)	O
is	O
an	O
enhancement	O
to	O
Cisco	B-Protocol
Discovery	I-Protocol
Protocol	I-Protocol
(	O
CDP	O
)	O
,	O
a	O
protocol	O
used	O
to	O
discover	O
other	O
Cisco	O
devices	O
on	O
either	O
broadcast	O
or	O
non-broadcast	O
media	O
.	O
</s>
<s>
With	O
the	O
help	O
of	O
CDP	O
,	O
it	O
is	O
possible	O
to	O
find	O
the	O
device	O
type	O
,	O
the	O
IP	B-Protocol
address	I-Protocol
,	O
the	O
Cisco	B-Protocol
IOS	I-Protocol
version	O
running	O
on	O
the	O
neighbor	O
Cisco	O
device	O
,	O
the	O
capabilities	O
of	O
the	O
neighbor	O
device	O
,	O
and	O
so	O
on	O
.	O
</s>
<s>
In	O
Cisco	B-Protocol
IOS	I-Protocol
software	O
release	O
11.2	O
,	O
ODR	O
was	O
added	O
to	O
CDP	O
to	O
advertise	O
the	O
connected	O
IP	B-Protocol
prefix	I-Protocol
of	O
a	O
stub	B-Protocol
router	I-Protocol
via	O
CDP	O
.	O
</s>
<s>
This	O
feature	O
takes	O
an	O
extra	O
five	O
bytes	O
for	O
each	O
network	O
or	O
subnet	B-Protocol
,	O
four	O
Bytes	O
for	O
the	O
IP	B-Protocol
address	I-Protocol
,	O
and	O
one	O
byte	O
to	O
advertise	O
the	O
subnet	B-Protocol
mask	I-Protocol
along	O
with	O
the	O
IP	O
.	O
</s>
<s>
ODR	O
is	O
able	O
to	O
carry	O
Variable	B-Protocol
Length	I-Protocol
Subnet	I-Protocol
Mask	I-Protocol
(	O
VLSM	O
)	O
information	O
.	O
</s>
