<s>
A	O
multi-chassis	B-Protocol
link	I-Protocol
aggregation	I-Protocol
group	I-Protocol
(	O
MLAG	B-Protocol
or	O
MC-LAG	B-Protocol
)	O
is	O
a	O
type	O
of	O
link	B-Architecture
aggregation	I-Architecture
group	I-Architecture
(	O
LAG	O
)	O
with	O
constituent	O
ports	O
that	O
terminate	O
on	O
separate	O
chassis	O
,	O
primarily	O
for	O
the	O
purpose	O
of	O
providing	O
redundancy	O
in	O
the	O
event	O
one	O
of	O
the	O
chassis	O
fails	O
.	O
</s>
<s>
The	O
IEEE	O
802.1AX-2008	O
industry	O
standard	O
for	O
link	B-Architecture
aggregation	I-Architecture
does	O
not	O
mention	O
MC-LAG	B-Protocol
,	O
but	O
does	O
not	O
preclude	O
it	O
.	O
</s>
<s>
A	O
LAG	O
is	O
a	O
method	O
of	O
inverse	B-Protocol
multiplexing	I-Protocol
over	O
multiple	O
Ethernet	O
links	O
,	O
thereby	O
increasing	O
bandwidth	O
and	O
providing	O
redundancy	O
.	O
</s>
<s>
It	O
is	O
defined	O
by	O
the	O
IEEE	O
802.1AX-2008	O
standard	O
,	O
which	O
states	O
,	O
"	O
Link	B-Architecture
Aggregation	I-Architecture
allows	O
one	O
or	O
more	O
links	O
to	O
be	O
aggregated	O
together	O
to	O
form	O
a	O
Link	B-Architecture
Aggregation	I-Architecture
Group	I-Architecture
,	O
such	O
that	O
a	O
MAC	B-Protocol
client	O
can	O
treat	O
the	O
Link	B-Architecture
Aggregation	I-Architecture
Group	I-Architecture
as	O
if	O
it	O
were	O
a	O
single	O
link.	O
"	O
</s>
<s>
This	O
layer	O
2	O
transparency	O
is	O
achieved	O
by	O
the	O
LAG	O
using	O
a	O
single	O
MAC	B-Protocol
address	O
for	O
all	O
the	O
device	O
’s	O
ports	O
in	O
the	O
LAG	O
group	O
.	O
</s>
<s>
Dynamic	O
LAG	O
uses	O
a	O
peer-to-peer	O
protocol	O
for	O
control	O
,	O
called	O
Link	B-Architecture
Aggregation	I-Architecture
Control	O
Protocol	O
(	O
LACP	O
)	O
.	O
</s>
<s>
MC-LAG	B-Protocol
adds	O
node-level	O
redundancy	O
to	O
the	O
normal	O
link-level	O
redundancy	O
that	O
a	O
LAG	O
provides	O
.	O
</s>
<s>
Note	O
that	O
MC-LAG	B-Protocol
implementations	O
are	O
vendor-specific	O
,	O
but	O
cooperating	O
chassis	O
remain	O
externally	O
compliant	O
to	O
the	O
IEEE	O
802.1AX-2008	O
standard	O
.	O
</s>
<s>
Nodes	O
in	O
an	O
MC-LAG	B-Protocol
cluster	O
communicate	O
to	O
synchronize	O
and	O
negotiate	O
automatic	O
switchovers	O
(	O
failover	O
)	O
.	O
</s>
<s>
The	O
following	O
table	O
lists	O
known	O
vendor	O
implementations	O
of	O
MC-LAG	B-Protocol
,	O
all	O
of	O
which	O
are	O
proprietary	O
.	O
</s>
<s>
IEEE	B-Protocol
802.1aq	I-Protocol
(	O
Shortest	B-Protocol
Path	I-Protocol
Bridging	I-Protocol
)	O
is	O
an	O
alternative	O
to	O
MC-LAG	B-Protocol
that	O
can	O
be	O
used	O
for	O
complex	O
networks	O
.	O
</s>
<s>
TRILL	B-Protocol
(	O
TRansparent	B-Protocol
Interconnection	I-Protocol
of	I-Protocol
Lots	I-Protocol
of	I-Protocol
Links	I-Protocol
)	O
facilitates	O
an	O
Ethernet	O
to	O
have	O
an	O
arbitrary	O
topology	O
,	O
and	O
enables	O
per	O
flow	O
pair-wise	O
load	O
splitting	O
by	O
way	O
of	O
Dijkstra	B-Algorithm
's	I-Algorithm
algorithm	I-Algorithm
,	O
without	O
configuration	O
and	O
user	O
intervention	O
.	O
</s>
