<s>
The	O
Distance	B-Protocol
Vector	I-Protocol
Multicast	I-Protocol
Routing	I-Protocol
Protocol	I-Protocol
(	O
DVMRP	B-Protocol
)	O
,	O
defined	O
in	O
,	O
is	O
a	O
routing	B-Protocol
protocol	I-Protocol
used	O
to	O
share	O
information	O
between	O
routers	B-Protocol
to	O
facilitate	O
the	O
transportation	O
of	O
IP	B-Protocol
multicast	I-Protocol
packets	O
among	O
networks	O
.	O
</s>
<s>
It	O
formed	O
the	O
basis	O
of	O
the	O
Internet	O
's	O
historic	O
multicast	B-Protocol
backbone	I-Protocol
,	O
Mbone	B-Protocol
.	O
</s>
<s>
The	O
protocol	O
is	O
based	O
on	O
the	O
Routing	B-Protocol
Information	I-Protocol
Protocol	I-Protocol
(	O
RIP	O
)	O
.	O
</s>
<s>
The	O
router	B-Protocol
generates	O
a	O
routing	O
table	O
with	O
the	O
multicast	O
group	O
of	O
which	O
it	O
has	O
knowledge	O
with	O
corresponding	O
distances	O
(	O
i.e.	O
</s>
<s>
number	O
of	O
devices/routers	O
between	O
the	O
router	B-Protocol
and	O
the	O
destination	O
)	O
.	O
</s>
<s>
When	O
a	O
multicast	O
packet	O
is	O
received	O
by	O
a	O
router	B-Protocol
,	O
it	O
is	O
forwarded	O
by	O
the	O
router	B-Protocol
's	O
interfaces	O
specified	O
in	O
the	O
routing	O
table	O
.	O
</s>
<s>
DVMRP	B-Protocol
operates	O
via	O
a	O
reverse	O
path	O
flooding	O
technique	O
,	O
sending	O
a	O
copy	O
of	O
a	O
received	O
packet	O
(	O
specifically	O
IGMP	B-Protocol
messages	O
for	O
exchanging	O
routing	O
information	O
with	O
other	O
routers	B-Protocol
)	O
out	O
through	O
each	O
interface	O
except	O
the	O
one	O
at	O
which	O
the	O
packet	O
arrived	O
.	O
</s>
<s>
If	O
a	O
router	B-Protocol
(	O
i.e.	O
</s>
<s>
Being	O
a	O
naïve	O
distance-vector	O
protocol	O
,	O
DVMRP	B-Protocol
has	O
difficulties	O
with	O
network	O
scaling	O
in	O
some	O
topologies	O
,	O
primarily	O
due	O
to	O
the	O
periodic	O
reflooding	O
necessary	O
to	O
detect	O
new	O
hosts	O
.	O
</s>
<s>
DVMRP	B-Protocol
's	O
flat	O
unicast	O
routing	O
mechanism	O
,	O
which	O
is	O
used	O
to	O
determine	O
the	O
source	O
interface	O
of	O
a	O
data	O
stream	O
,	O
also	O
affects	O
its	O
ability	O
to	O
scale	O
.	O
</s>
