<s>
Zone	B-Protocol
Routing	I-Protocol
Protocol	I-Protocol
,	O
or	O
ZRP	O
is	O
a	O
hybrid	O
Wireless	O
Networking	O
routing	B-Protocol
protocol	I-Protocol
that	O
uses	O
both	O
proactive	O
and	O
reactive	O
routing	B-Protocol
protocols	I-Protocol
when	O
sending	O
information	O
over	O
the	O
network	O
.	O
</s>
<s>
If	O
a	O
packet	O
's	O
destination	O
is	O
in	O
the	O
same	O
zone	O
as	O
the	O
origin	O
,	O
the	O
proactive	O
protocol	O
using	O
an	O
already	O
stored	O
routing	B-Protocol
table	I-Protocol
is	O
used	O
to	O
deliver	O
the	O
packet	O
immediately	O
.	O
</s>
<s>
In	O
this	O
way	O
packets	O
with	O
destinations	O
within	O
the	O
same	O
zone	O
as	O
the	O
originating	O
zone	O
are	O
delivered	O
immediately	O
using	O
a	O
stored	O
routing	B-Protocol
table	I-Protocol
.	O
</s>
<s>
Packets	O
delivered	O
to	O
nodes	O
outside	O
the	O
sending	O
zone	O
avoid	O
the	O
overhead	O
of	O
checking	O
routing	B-Protocol
tables	I-Protocol
along	O
the	O
way	O
by	O
using	O
the	O
reactive	O
protocol	O
to	O
check	O
whether	O
each	O
zone	O
encountered	O
contains	O
the	O
destination	O
node	O
.	O
</s>
<s>
Thus	O
ZRP	O
reduces	O
the	O
control	O
overhead	O
for	O
longer	O
routes	O
that	O
would	O
be	O
necessary	O
if	O
using	O
proactive	O
routing	B-Protocol
protocols	I-Protocol
throughout	O
the	O
entire	O
route	O
,	O
while	O
eliminating	O
the	O
delays	O
for	O
routing	O
within	O
a	O
zone	O
that	O
would	O
be	O
caused	O
by	O
the	O
route-discovery	O
processes	O
of	O
reactive	O
routing	B-Protocol
protocols	I-Protocol
.	O
</s>
<s>
What	O
is	O
called	O
the	O
Intra-zone	O
Routing	B-Protocol
Protocol	I-Protocol
(	O
IARP	O
)	O
,	O
or	O
a	O
proactive	O
routing	B-Protocol
protocol	I-Protocol
,	O
is	O
used	O
inside	O
routing	O
zones	O
.	O
</s>
<s>
What	O
is	O
called	O
the	O
Inter-zone	O
Routing	B-Protocol
Protocol	I-Protocol
(	O
IERP	O
)	O
,	O
or	O
a	O
reactive	O
routing	B-Protocol
protocol	I-Protocol
,	O
is	O
used	O
between	O
routing	O
zones	O
.	O
</s>
<s>
IARP	O
uses	O
a	O
routing	B-Protocol
table	I-Protocol
.	O
</s>
<s>
Any	O
route	O
to	O
a	O
destination	O
that	O
is	O
within	O
the	O
same	O
local	O
zone	O
is	O
quickly	O
established	O
from	O
the	O
source	O
's	O
proactively	O
cached	O
routing	B-Protocol
table	I-Protocol
by	O
IARP	O
.	O
</s>
