<s>
In	O
computer	B-Architecture
networking	I-Architecture
,	O
jumbo	B-Protocol
frames	I-Protocol
are	O
Ethernet	B-Protocol
frames	I-Protocol
with	O
more	O
than	O
1500	O
bytes	O
of	O
payload	O
,	O
the	O
limit	O
set	O
by	O
the	O
IEEE	O
802.3	O
standard	O
.	O
</s>
<s>
Commonly	O
,	O
jumbo	B-Protocol
frames	I-Protocol
can	O
carry	O
up	O
to	O
9000	O
bytes	O
of	O
payload	O
,	O
but	O
smaller	O
and	O
larger	O
variations	O
exist	O
and	O
some	O
care	O
must	O
be	O
taken	O
using	O
the	O
term	O
.	O
</s>
<s>
Many	O
Gigabit	O
Ethernet	O
switches	O
and	O
Gigabit	O
Ethernet	O
network	B-Protocol
interface	I-Protocol
controllers	I-Protocol
and	O
some	O
Fast	B-Protocol
Ethernet	I-Protocol
switches	O
and	O
Fast	B-Protocol
Ethernet	I-Protocol
network	B-Protocol
interface	I-Protocol
cards	I-Protocol
can	O
support	O
jumbo	B-Protocol
frames	I-Protocol
.	O
</s>
<s>
Each	O
Ethernet	B-Protocol
frame	I-Protocol
must	O
be	O
processed	O
as	O
it	O
passes	O
through	O
the	O
network	O
.	O
</s>
<s>
Jumbo	B-Protocol
frames	I-Protocol
gained	O
initial	O
prominence	O
in	O
1998	O
,	O
when	O
Alteon	O
WebSystems	O
introduced	O
them	O
in	O
their	O
ACEnic	O
Gigabit	O
Ethernet	B-Protocol
adapters	I-Protocol
.	O
</s>
<s>
Many	O
other	O
vendors	O
also	O
adopted	O
the	O
size	O
;	O
however	O
,	O
jumbo	B-Protocol
frames	I-Protocol
are	O
not	O
part	O
of	O
the	O
official	O
IEEE	O
802.3	O
Ethernet	O
standard	O
.	O
</s>
<s>
Jumbo	B-Protocol
frames	I-Protocol
have	O
the	O
potential	O
to	O
reduce	O
overheads	O
and	O
CPU	O
cycles	O
and	O
have	O
a	O
positive	O
effect	O
on	O
end-to-end	O
TCP	B-Protocol
performance	O
.	O
</s>
<s>
The	O
presence	O
of	O
jumbo	B-Protocol
frames	I-Protocol
may	O
have	O
an	O
adverse	O
effect	O
on	O
network	O
latency	O
,	O
especially	O
on	O
low-bandwidth	O
links	O
.	O
</s>
<s>
802.5	B-Device
Token	I-Device
Ring	I-Device
can	O
support	O
frames	O
with	O
a	O
4464-byte	O
MTU	B-Protocol
,	O
FDDI	B-Protocol
can	O
transport	O
4352-byte	O
,	O
ATM	O
9180-byte	O
and	O
802.11	O
can	O
transport	O
7935-byte	O
MTUs	B-Protocol
.	O
</s>
<s>
The	O
IEEE	O
802.3	O
Ethernet	O
standard	O
originally	O
mandated	O
support	O
for	O
1500-byte	O
MTU	B-Protocol
frames	O
,	O
1518	O
byte	O
total	O
frame	O
size	O
(	O
1522	O
byte	O
with	O
the	O
optional	O
IEEE	O
802.1Q	O
VLAN/QoS	O
tag	O
)	O
.	O
</s>
<s>
The	O
IEEE	O
802.3as	O
update	O
grandfathered	O
in	O
multiple	O
common	O
headers	O
,	O
trailers	O
,	O
and	O
encapsulations	O
by	O
creating	O
the	O
concept	O
of	O
an	O
envelope	O
where	O
up	O
to	O
482	O
bytes	O
of	O
header	O
and	O
trailer	O
could	O
be	O
included	O
,	O
and	O
the	O
largest	O
IEEE	O
802.3	O
supported	O
Ethernet	B-Protocol
frame	I-Protocol
became	O
2000	O
bytes	O
.	O
</s>
<s>
The	O
use	O
of	O
9000	O
bytes	O
as	O
preferred	O
payload	O
size	O
for	O
jumbo	B-Protocol
frames	I-Protocol
arose	O
from	O
discussions	O
within	O
the	O
Joint	O
Engineering	O
Team	O
of	O
Internet2	O
and	O
the	O
U.S.	O
federal	O
government	O
networks	O
.	O
</s>
<s>
Manufacturers	O
have	O
in	O
turn	O
adopted	O
9000	O
bytes	O
as	O
the	O
conventional	O
MTU	B-Protocol
size	O
,	O
with	O
a	O
total	O
jumbo	B-Protocol
frame	I-Protocol
size	O
of	O
between	O
9014	O
and	O
9022	O
bytes	O
with	O
ethernet	O
headers	O
included	O
.	O
</s>
<s>
Most	O
Ethernet	O
equipment	O
can	O
support	O
jumbo	B-Protocol
frames	I-Protocol
up	O
to	O
9216	O
bytes	O
.	O
</s>
<s>
IEEE	B-Protocol
802.1AB-2009	I-Protocol
and	O
IEEE	O
802.3bc-2009	O
added	O
LLDP	B-Protocol
discovery	O
to	O
standard	O
Ethernet	O
for	O
maximum	O
frame	O
length	O
(	O
TLV	B-Protocol
subtype	O
4	O
)	O
.	O
</s>
<s>
Simple	O
additive	O
checksums	O
as	O
contained	O
within	O
the	O
UDP	B-Protocol
and	O
TCP	B-Protocol
transports	O
have	O
proven	O
ineffective	O
at	O
detecting	O
bus-specific	O
bit	O
errors	O
because	O
with	O
simple	O
summations	O
,	O
these	O
errors	O
tend	O
to	O
self-cancel	O
.	O
</s>
<s>
Before	O
the	O
adoption	O
of	O
RFC	O
3309	O
(	O
SCTP	B-Protocol
,	O
CRC32c	O
)	O
,	O
testing	O
with	O
simulated	O
error	O
injection	O
against	O
real	O
data	O
showed	O
that	O
as	O
much	O
as	O
2%	O
of	O
these	O
errors	O
were	O
not	O
being	O
detected	O
.	O
</s>
<s>
Larger	O
frames	O
are	O
more	O
likely	O
to	O
suffer	O
undetected	O
errors	O
with	O
the	O
simple	O
CRC32	O
error	O
detection	O
used	O
in	O
Ethernet	B-Protocol
frames	I-Protocol
–	O
as	O
packet	O
size	O
increases	O
it	O
becomes	O
more	O
likely	O
that	O
multiple	O
errors	O
cancel	O
each	O
other	O
out	O
.	O
</s>
<s>
One	O
IETF	O
approach	O
for	O
adopting	O
jumbo	B-Protocol
frames	I-Protocol
avoids	O
data	O
integrity	O
reduction	O
of	O
the	O
service	O
data	O
unit	O
by	O
performing	O
an	O
extra	O
CRC	O
at	O
the	O
next	O
network	O
protocol	O
layer	O
above	O
Ethernet	O
.	O
</s>
<s>
Stream	B-Protocol
Control	I-Protocol
Transmission	I-Protocol
Protocol	I-Protocol
(	O
SCTP	B-Protocol
)	O
transport	O
(	O
RFC	O
4960	O
)	O
and	O
iSCSI	O
(	O
RFC	O
7143	O
)	O
use	O
the	O
Castagnoli	O
CRC	O
polynomial	O
.	O
</s>
<s>
The	O
Castagnoli	O
polynomial	O
0x1EDC6F41	O
achieves	O
the	O
Hamming	O
distance	O
HD	O
=	O
6	O
beyond	O
one	O
Ethernet	O
MTU	B-Protocol
(	O
to	O
a	O
16,360	O
-bit	O
data	O
word	O
length	O
)	O
and	O
HD	O
=	O
4	O
to	O
114,663	O
bits	O
,	O
which	O
is	O
more	O
than	O
9	O
times	O
the	O
length	O
of	O
an	O
Ethernet	O
MTU	B-Protocol
.	O
</s>
<s>
This	O
gives	O
two	O
additional	O
bits	O
of	O
error	O
detection	O
ability	O
at	O
MTU-sized	O
data	O
words	O
compared	O
to	O
the	O
Ethernet	O
CRC	O
standard	O
polynomial	O
while	O
not	O
sacrificing	O
HD	O
=	O
4	O
capability	O
for	O
data	O
word	O
sizes	O
up	O
to	O
and	O
beyond	O
72kbits	O
.	O
</s>
<s>
Support	O
of	O
Castagnoli	O
CRC	O
polynomial	O
within	O
a	O
general-purpose	O
transport	O
designed	O
to	O
handle	O
data	O
chunks	O
,	O
and	O
within	O
a	O
TCP	B-Protocol
transport	O
designed	O
to	O
carry	O
SCSI	O
data	O
,	O
both	O
provide	O
improved	O
error	O
detection	O
rates	O
despite	O
the	O
use	O
of	O
jumbo	B-Protocol
frames	I-Protocol
where	O
an	O
increase	O
of	O
the	O
Ethernet	O
MTU	B-Protocol
would	O
otherwise	O
have	O
resulted	O
in	O
a	O
significant	O
reduction	O
in	O
error	O
detection	O
.	O
</s>
<s>
Some	O
vendors	O
include	O
the	O
headers	O
in	O
the	O
size	O
settings	O
while	O
others	O
do	O
not	O
,	O
that	O
is	O
either	O
the	O
maximum	O
frame	O
size	O
(	O
including	O
frame	O
headers	O
,	O
maximum	O
layer-2	O
packet	O
size	O
)	O
or	O
the	O
maximum	B-Protocol
transmission	I-Protocol
unit	I-Protocol
(	O
maximum	O
layer	O
3	O
packet	O
size	O
excluding	O
frame	O
headers	O
)	O
.	O
</s>
<s>
A	O
mixture	O
of	O
devices	O
configured	O
for	O
jumbo	B-Protocol
frames	I-Protocol
and	O
devices	O
not	O
configured	O
for	O
jumbo	B-Protocol
frames	I-Protocol
on	O
a	O
network	O
has	O
the	O
potential	O
to	O
cause	O
network	O
performance	O
issues	O
.	O
</s>
<s>
Jumbo	B-Protocol
frames	I-Protocol
can	O
increase	O
the	O
efficiency	O
of	O
Ethernet	O
and	O
network	O
processing	O
in	O
hosts	O
by	O
reducing	O
the	O
protocol	O
overhead	O
,	O
as	O
shown	O
in	O
the	O
following	O
example	O
with	O
TCP	B-Protocol
over	O
IPv4	B-Protocol
.	O
</s>
<s>
A	O
host	O
that	O
uses	O
its	O
network	B-Protocol
interface	I-Protocol
controller	I-Protocol
's	O
TCP	B-Protocol
offload	I-Protocol
engine	I-Protocol
with	O
already	O
reduced	O
overhead	O
receives	O
less	O
benefit	O
than	O
a	O
host	O
that	O
processes	O
frames	O
with	O
its	O
CPU	O
.	O
</s>
<s>
Baby	O
giant	O
or	O
baby	O
jumbo	B-Protocol
frames	I-Protocol
are	O
Ethernet	B-Protocol
frames	I-Protocol
that	O
are	O
only	O
slightly	O
larger	O
than	O
allowed	O
by	O
the	O
IEEE	O
Ethernet	O
standards	O
.	O
</s>
<s>
Baby	O
giant	O
frames	O
are	O
,	O
for	O
example	O
,	O
required	O
for	O
IP/MPLS	B-Protocol
over	O
Ethernet	O
to	O
deliver	O
Ethernet	O
services	O
with	O
standard	O
1500	O
byte	O
payloads	O
.	O
</s>
<s>
Most	O
implementations	O
will	O
require	O
non-jumbo	O
user	O
frames	O
to	O
be	O
encapsulated	O
into	O
MPLS	B-Protocol
frame	O
format	O
which	O
in	O
turn	O
may	O
be	O
encapsulated	O
into	O
a	O
proper	O
Ethernet	B-Protocol
frame	I-Protocol
format	O
with	O
EtherType	B-Protocol
values	O
of	O
0x8847	O
and	O
0x8848	O
.	O
</s>
<s>
The	O
increased	O
overhead	O
of	O
extra	O
MPLS	B-Protocol
and	O
Ethernet	O
headers	O
means	O
that	O
the	O
support	O
for	O
frames	O
up	O
to	O
1600	O
bytes	O
is	O
required	O
in	O
Carrier	B-Protocol
Ethernet	I-Protocol
networks	O
.	O
</s>
<s>
Jumbo	B-Protocol
frames	I-Protocol
for	O
PPPoE	B-Protocol
is	O
defined	O
in	O
RFC	O
4638	O
,	O
with	O
the	O
purpose	O
of	O
removing	O
the	O
old	O
1492-byte	O
limit	O
(	O
originally	O
defined	O
because	O
PPP	O
needs	O
8	O
more	O
bytes	O
of	O
overhead	O
)	O
,	O
so	O
that	O
normal	O
1500-byte	O
Ethernet	O
can	O
run	O
without	O
fragmentation	O
.	O
</s>
<s>
The	O
"	O
PPP-Max-Payload	O
"	O
tag	O
can	O
still	O
accommodate	O
much	O
larger	O
,	O
non-baby	O
jumbo	B-Protocol
frames	I-Protocol
.	O
</s>
<s>
Super	B-Protocol
jumbo	I-Protocol
frames	I-Protocol
(	O
SJFs	O
)	O
are	O
frames	O
that	O
have	O
a	O
payload	O
size	O
over	O
9000	O
bytes	O
.	O
</s>
<s>
As	O
it	O
has	O
been	O
a	O
relatively	O
difficult	O
,	O
and	O
somewhat	O
lengthy	O
,	O
process	O
to	O
increase	O
the	O
path	O
MTU	B-Protocol
of	O
high-performance	O
national	O
research	O
and	O
education	O
networks	O
from	O
1500	O
bytes	O
to	O
9000	O
bytes	O
or	O
so	O
,	O
a	O
subsequent	O
increase	O
,	O
possibly	O
to	O
64,000	O
bytes	O
,	O
is	O
under	O
consideration	O
.	O
</s>
<s>
The	O
Total	O
Length	O
field	O
of	O
IPv4	B-Protocol
and	O
the	O
Payload	O
Length	O
field	O
of	O
IPv6	B-Protocol
each	O
have	O
a	O
size	O
of	O
16	O
bits	O
,	O
thus	O
allowing	O
data	O
of	O
up	O
to	O
.	O
</s>
<s>
IPv6	B-Protocol
's	O
jumbo	O
payload	O
option	O
allows	O
for	O
up	O
to	O
4GiB	O
(	O
2-1	O
bytes	O
)	O
payload	O
.	O
</s>
<s>
These	O
theoretical	O
limits	O
for	O
the	O
Internet	B-Protocol
Protocol	I-Protocol
(	O
IP	O
)	O
MTU	B-Protocol
,	O
however	O
,	O
are	O
reached	O
only	O
on	O
networks	O
that	O
have	O
a	O
suitable	O
link-layer	O
infrastructure	O
.	O
</s>
<s>
Large	B-Protocol
send	I-Protocol
offload	I-Protocol
and	O
large	B-Device
receive	I-Device
offload	I-Device
offload	O
per-frame	O
processing	O
making	O
CPU	O
load	O
largely	O
independent	O
of	O
frame	O
size	O
.	O
</s>
<s>
It	O
is	O
another	O
way	O
to	O
eliminate	O
the	O
per-packet	O
overhead	O
that	O
jumbo	B-Protocol
frames	I-Protocol
were	O
designed	O
to	O
reduce	O
.	O
</s>
<s>
Jumbo	B-Protocol
frames	I-Protocol
are	O
still	O
useful	O
from	O
a	O
bandwidth	O
perspective	O
,	O
as	O
they	O
reduce	O
the	O
amount	O
of	O
bandwidth	O
used	O
for	O
non-data	O
overhead	O
.	O
</s>
