<s>
MAC-Forced	B-Protocol
Forwarding	I-Protocol
(	O
MACFF	B-Protocol
)	O
is	O
used	O
to	O
control	O
unwanted	O
broadcast	O
traffic	O
and	O
host-to-host	O
communication	O
.	O
</s>
<s>
MACFF	B-Protocol
is	O
suitable	O
for	O
Ethernet	O
networks	O
where	O
a	O
layer	O
2	O
bridging	O
device	O
,	O
known	O
as	O
an	O
Ethernet	O
Access	O
Node	O
(	O
EAN	O
)	O
,	O
connects	O
Access	O
Routers	O
to	O
their	O
clients	O
.	O
</s>
<s>
MACFF	B-Protocol
is	O
configured	O
on	O
the	O
EANs	O
.	O
</s>
<s>
MACFF	B-Protocol
is	O
described	O
in	O
RFC	O
4562	O
,	O
MAC-Forced	B-Protocol
Forwarding	I-Protocol
:	O
A	O
Method	O
for	O
Subscriber	O
Separation	O
on	O
an	O
Ethernet	O
Access	O
Network	O
.	O
</s>
<s>
Allied	O
Telesis	O
switches	O
implement	O
MACFF	B-Protocol
using	O
DHCP	B-Protocol
snooping	I-Protocol
to	O
maintain	O
a	O
database	O
of	O
the	O
hosts	O
that	O
appear	O
on	O
each	O
switch	O
port	O
.	O
</s>
<s>
When	O
a	O
host	O
tries	O
to	O
access	O
the	O
network	O
through	O
a	O
switch	O
port	O
,	O
DHCP	B-Protocol
snooping	I-Protocol
checks	O
the	O
host	O
’s	O
IP	O
address	O
against	O
the	O
database	O
to	O
ensure	O
that	O
the	O
host	O
is	O
valid	O
.	O
</s>
<s>
MACFF	B-Protocol
then	O
uses	O
DHCP	B-Protocol
snooping	I-Protocol
to	O
check	O
whether	O
the	O
host	O
has	O
a	O
gateway	O
Access	O
Router	O
.	O
</s>
<s>
If	O
it	O
does	O
,	O
MACFF	B-Protocol
uses	O
a	O
form	O
of	O
Proxy	B-Protocol
ARP	I-Protocol
to	O
reply	O
to	O
any	O
ARP	O
requests	O
,	O
giving	O
the	O
router	O
's	O
MAC	O
address	O
.	O
</s>
