<s>
An	O
interior	B-Protocol
gateway	I-Protocol
protocol	I-Protocol
(	O
IGP	O
)	O
or	O
Interior	B-Protocol
routing	I-Protocol
protocol	I-Protocol
is	O
a	O
type	O
of	O
routing	B-Protocol
protocol	I-Protocol
used	O
for	O
exchanging	O
routing	B-Protocol
table	I-Protocol
information	O
between	O
gateways	O
(	O
commonly	O
routers	B-Protocol
)	O
within	O
an	O
autonomous	B-Architecture
system	I-Architecture
(	O
for	O
example	O
,	O
a	O
system	O
of	O
corporate	O
local	O
area	O
networks	O
)	O
.	O
</s>
<s>
This	O
routing	O
information	O
can	O
then	O
be	O
used	O
to	O
route	O
network-layer	B-Application
protocols	I-Application
like	O
IP	B-Protocol
.	O
</s>
<s>
Interior	B-Protocol
gateway	I-Protocol
protocols	I-Protocol
can	O
be	O
divided	O
into	O
two	O
categories	O
:	O
distance-vector	B-Protocol
routing	I-Protocol
protocols	I-Protocol
and	O
link-state	B-Protocol
routing	I-Protocol
protocols	I-Protocol
.	O
</s>
<s>
Specific	O
examples	O
of	O
IGPs	O
include	O
Open	B-Protocol
Shortest	I-Protocol
Path	I-Protocol
First	I-Protocol
(	O
OSPF	B-Protocol
)	O
,	O
Routing	B-Protocol
Information	I-Protocol
Protocol	I-Protocol
(	O
RIP	O
)	O
,	O
Intermediate	B-Protocol
System	I-Protocol
to	I-Protocol
Intermediate	I-Protocol
System	I-Protocol
(	O
IS-IS	B-Protocol
)	O
and	O
Enhanced	B-Protocol
Interior	I-Protocol
Gateway	I-Protocol
Routing	I-Protocol
Protocol	I-Protocol
(	O
EIGRP	B-Protocol
)	O
.	O
</s>
<s>
By	O
contrast	O
,	O
exterior	B-Protocol
gateway	I-Protocol
protocols	I-Protocol
are	O
used	O
to	O
exchange	O
routing	O
information	O
between	O
autonomous	B-Architecture
systems	I-Architecture
and	O
rely	O
on	O
IGPs	O
to	O
resolve	O
routes	O
within	O
an	O
autonomous	B-Architecture
system	I-Architecture
.	O
</s>
<s>
Examples	O
of	O
distance-vector	B-Protocol
routing	I-Protocol
protocols	I-Protocol
:	O
</s>
<s>
Examples	O
of	O
link-state	B-Protocol
routing	I-Protocol
protocols	I-Protocol
:	O
</s>
<s>
Advanced	O
distance	B-Protocol
vector	I-Protocol
routing	I-Protocol
protocols	I-Protocol
have	O
both	O
the	O
features	O
of	O
distance	B-Protocol
vector	I-Protocol
routing	I-Protocol
protocols	I-Protocol
and	O
link-state	B-Protocol
routing	I-Protocol
protocols	I-Protocol
.	O
</s>
<s>
One	O
example	O
is	O
Enhanced	B-Protocol
Interior	I-Protocol
Gateway	I-Protocol
Routing	I-Protocol
Protocol	I-Protocol
(	O
EIGRP	B-Protocol
)	O
.	O
</s>
