<s>
SCION	B-Protocol
(	O
Scalability	O
,	O
Control	O
,	O
and	O
Isolation	O
On	O
Next-Generation	O
Networks	O
)	O
is	O
a	O
modern	O
Future	B-Architecture
Internet	I-Architecture
architecture	O
that	O
aims	O
to	O
offer	O
high	O
availability	O
and	O
efficient	O
point-to-point	O
packet	O
delivery	O
,	O
even	O
in	O
the	O
presence	O
of	O
actively	O
malicious	O
network	O
operators	O
and	O
devices	O
.	O
</s>
<s>
As	O
of	O
2018	O
it	O
is	O
an	O
ongoing	O
research	O
project	O
lead	O
by	O
researchers	O
at	O
ETH	O
Zurich	O
and	O
,	O
among	O
other	O
Future	B-Architecture
Internet	I-Architecture
proposals	O
,	O
is	O
being	O
explored	O
in	O
the	O
Internet	O
Engineering	O
Task	O
Force	O
research	O
group	O
for	O
path-aware	O
networking	O
.	O
</s>
<s>
Transparency	O
and	O
Control	O
:	O
Separation	O
of	O
control	O
and	O
data	O
planes	O
by	O
encoding	O
paths	O
as	O
packet-carried	O
forwarding	O
state	O
(	O
PCFS	O
)	O
in	O
the	O
packet	O
header	O
,	O
as	O
well	O
as	O
enabling	O
of	O
multipath	B-Protocol
communication	I-Protocol
for	O
enhanced	O
availability	O
and	O
defense	O
against	O
network	O
attacks	O
.	O
</s>
<s>
Efficiency	O
,	O
Scalability	O
,	O
and	O
Extensibility	O
:	O
Packet	O
forwarding	O
is	O
at	O
least	O
efficient	O
in	O
latency	O
and	O
throughput	O
as	O
current	O
IP	B-Protocol
in	O
common	O
cases	O
and	O
more	O
scalable	O
with	O
respect	O
to	O
BGP	B-Protocol
and	O
the	O
size	O
of	O
routing	O
tables	O
.	O
</s>
<s>
Achieved	O
by	O
storing	O
state	O
in	O
packet	O
headers	O
and	O
protecting	O
them	O
cryptographically	O
,	O
using	O
modern	O
block	O
ciphers	O
such	O
as	O
AES	B-Algorithm
that	O
can	O
be	O
computed	O
very	O
efficiently	O
(	O
within	O
10ns	O
on	O
a	O
modern	O
CPU	O
)	O
.	O
</s>
<s>
SCION	B-Protocol
introduces	O
the	O
concept	O
of	O
an	O
isolation	O
domain	O
(	O
ISD	O
)	O
which	O
is	O
a	O
logical	O
grouping	O
of	O
autonomous	B-Architecture
systems	I-Architecture
(	O
ASes	O
)	O
,	O
administered	O
by	O
a	O
smaller	O
subset	O
of	O
the	O
ASes	O
that	O
constitute	O
the	O
ISD	O
core	O
.	O
</s>
<s>
Border	O
Routers	O
-	O
used	O
for	O
SCION	B-Protocol
packet	O
forwarding	O
to	O
the	O
next	O
SCION	B-Protocol
border	O
router	O
or	O
to	O
the	O
destination	O
host	O
within	O
the	O
destination	O
AS	O
.	O
</s>
<s>
The	O
SCION	B-Protocol
control	O
plane	O
operates	O
at	O
the	O
AS	O
level	O
,	O
while	O
communication	O
within	O
an	O
AS	O
is	O
governed	O
by	O
existing	O
intra-domain	O
communication	O
technologies	O
and	O
protocols	O
(	O
e.g.	O
</s>
<s>
OSPF	B-Protocol
,	O
SDN	O
,	O
MPLS	B-Protocol
)	O
.	O
</s>
<s>
A	O
SCION	B-Protocol
packet	O
minimally	O
contains	O
a	O
path	O
and	O
the	O
data	O
plane	O
ensures	O
packet	O
forwarding	O
using	O
the	O
provided	O
paths	O
.	O
</s>
<s>
Forwarding	O
utilizes	O
a	O
split	O
of	O
locator	O
(	O
AS-level	O
path	O
)	O
and	O
identifier	O
(	O
the	O
destination	O
address	O
)	O
,	O
like	O
in	O
the	O
Locator/Identifier	B-Protocol
Separation	I-Protocol
Protocol	I-Protocol
(	O
LISP	O
)	O
.	O
</s>
<s>
As	O
a	O
result	O
,	O
SCION	B-Protocol
border	O
routers	O
forward	O
packets	O
based	O
on	O
the	O
AS-level	O
path	O
in	O
the	O
packet	O
header	O
without	O
inspecting	O
the	O
destination	O
address	O
and	O
also	O
without	O
consulting	O
an	O
inter-domain	O
routing	O
table	O
.	O
</s>
<s>
Similar	O
to	O
BGPsec	B-Protocol
,	O
each	O
AS	O
signs	O
the	O
PCBs	O
it	O
forwards	O
.	O
</s>
<s>
Each	O
AS	O
uses	O
a	O
secret	O
symmetric	O
key	O
that	O
is	O
shared	O
among	O
beacon	O
servers	O
and	O
border	O
routers	O
and	O
is	O
used	O
to	O
efficiently	O
compute	O
a	O
message	B-Algorithm
authentication	I-Algorithm
code	I-Algorithm
(	O
MAC	O
)	O
over	O
the	O
forwarding	O
information	O
.	O
</s>
<s>
SCION	B-Protocol
is	O
running	O
on	O
a	O
number	O
of	O
nodes	O
around	O
the	O
world	O
.	O
</s>
<s>
"	O
In	O
2017	O
,	O
several	O
internet	O
service	O
providers	O
and	O
financial	O
institutions	O
in	O
Switzerland	O
wanted	O
to	O
use	O
SCION	B-Protocol
for	O
their	O
commercial	O
operations	O
.	O
</s>
<s>
The	O
first	O
ISPs	O
to	O
use	O
SCION	B-Protocol
are	O
Swisscom	O
and	O
SWITCH	O
.	O
</s>
<s>
Several	O
corporations	O
have	O
obtained	O
SCION	B-Protocol
network	O
connections	O
through	O
these	O
ISPs	O
to	O
the	O
corporate	O
SCION	B-Protocol
network	O
.	O
</s>
