Hi everyone, I'm Sangeetha Abdu-Jyothi. I'm an
assistant professor at the University of
California, Irvine and an affiliated researcher
at VMware Research. Today I'll be presenting
my work on understanding the impact of a cosmic
phenomenon that is capable of taking down
the internet, which is solar super storms. What
are the impacts of losing internet connectivity?
We know that it can affect our professional and
social lives significantly, especially
now during the pandemic. For large businesses,
the impact can be devastating. The revenue
loss per hour for some of the large companies are
estimated to be tens of millions of dollars.
And at the scale of countries, it can be hundreds
of millions per hour or in billions per day.
And it's not just the economic impact. Many of
the other critical infrastructure, such
as healthcare, that depend on the internet will
be severely affected as well. Now, what
if we have an internet outage lasting weeks or
months and spanning large areas across
the globe? One might think that such a global outage
is never going to happen because the
internet is a resilient distributed system, which
successfully withstood several natural
disasters and man-made attacks in the past.
Unfortunately, this is a worst case scenario
that could happen in our lifetime. The next once
in a hundred year disaster after this
pandemic could be a solar super storm that is
capable of taking down large parts of the
internet. Today, network researchers and
operators overlook this threat while building our
infrastructure.
In this talk, I present a deeper view of this
natural disaster and its impact on various
internet infrastructure components. There are two
types of solar events that are popularly
known as solar storms, solar flares and coronal
mass ejections or CMEs. Their impact on global
infrastructure varies widely. So solar flares
involve large amounts of emitted energy as
electromagnetic radiation. These are essentially
flashes of light and they reach the earth
in just eight minutes based on the speed of light.
Fortunately, they mostly affect only
the upper layers of the atmosphere and do not
cause any damages to terrestrial infrastructure,
but they do affect satellite communication. Coronal
mass ejections or CMEs involve the
emission of electrically charged solar matter and
the accompanying magnetic field into space.
And once these are emitted from the sun, they can
take anywhere from 13 hours to five days
to reach the earth based on their speed. And
these CMEs are capable of causing significant
damages to terrestrial infrastructure. Now CMEs
are the focus of this talk and we'll
discuss the impact more closely soon. Both solar
flares and CMEs originate near sunspots,
which are temporary dark spots on the sun caused
by concentration of magnetic field
flux. And when the number of sunspots increases,
there is a higher probability of both solar
flares and CMEs occurring. Now how do CMEs affect
us? The magnetized emissions of coronal
mass ejections are highly directional. And when
the earth is in the direct path of a
CME, it interacts with the earth's magnetic field
and large electric fields are produced
on the earth's surface through electromagnetic
induction. And this induced electric field
can cause geomagnetically induced currents to
flow through long cables like internet
cables or power transmission lines that have
ground connections that are located far apart
on the earth's crust. And these currents can
cause significant damages to these long distance
cables. And we know that cable repair, especially
in the ocean on submarine cables is very
expensive
and time consuming. Now what are some of the
characteristics of these induced currents?
So here due to the orientation of the earth's
magnetic field, higher latitudes are at a
significantly higher risk. This is because the
earth's magnetic poles are located closer
to the geographic poles as well. And it's for the
same reason that auroras are common
closer to the poles than the equator. Now since
the impact is caused by interaction
with the earth's magnetic field, the induced
currents can affect wide areas and they're
not restricted to the portion of the earth that
is facing the sun. And geomagnetically
induced currents are only induced in cables with
ground connections that are separated
by large distances and have an electrical
conductor that runs across that distance.
Another interesting thing is that conductors
along different orientations on earth are
at equal risk. In other words, the north, south
or east, west orientation of the cable
does not influence the induced current. The
induced electric fields can be in any direction.
Now the most important question is when will a
large event that actually affects us happen
next? Solar events are extremely hard to predict,
just like earthquakes or any other natural
disasters. And small scale solar storms happen
all the time. What we are more interested
in are solar super storms that can have a
significant impact on our lives. The largest
solar events on record occurred in 1859 and 1921,
long before the advent of modern technology
and the modern internet. The 1859 event in
particular is popularly known as the Carrington
event. And both these events triggered extensive
power outages across the globe and also caused
significant damages to the communication network
of that time, which was the telegraph network.
A Carrington scale event missed the earth by just
one week back in 2012. And the estimates
for probability of occurrence of such extreme
space weather, like the Carrington event of
the 1921 event, that directly impact the earth,
ranges from 1.6% to 12% per decade. But that's
not all. The risk is not uniform because the
solar activity goes through cycles. So here
we have the variation in the number of sunspots
across years. And so on the y-axis, we have
the number of sunspots and we have different
years from 1700 to 2020. And here we can see
that solar activity waxes and wanes in cycles of
period length approximately 11 years. And
during solar maxima, there's an increase in the
frequency of CMEs. In addition to the
11 year cycle, the solar activity also goes
through a longer term cycle of approximately
80 to 100 years. And this is called Gleisberg
cycle. And the peak solar activity, the peak
across these different solar cycles can vary
across the 100 year period. And this causes
the frequency of CMEs to vary by a factor of four
across the strongest and the weakest
cycles in a 100 year cycle. Now, if we look
closely at this plot, we can see that the
last three decades, where modern technological
advancement happened, and most of the internet
infrastructure was laid down, coincided with the
period of weak solar activity. In the
last three decades. Now we are at the beginning
of solar cycle 25, and the sun is expected
to become more active in the near future. And due
to the absence of extreme activity
in the recent past, we have overlooked the impact
of these events on the internet infrastructure.
So the bottom line here is that a large event
could happen sometime during our lifetime.
And the impact is big enough that we should
prepare our infrastructure for it. Now, the
next interesting question is how are various
internet components affected? So let's start
with wired infrastructure. Localized
infrastructure such as data centers can be
protected from
voltage surges caused by these CMEs using
transient voltage surge suppressors. And they
are relatively inexpensive. So if your
infrastructure is localized in some area, then it
can be
relatively easily protected. Long distance cables
constitute the most vulnerable components
in the internet infrastructure. So as we all know,
today's long distance LAN and sub mini
cables carry signals in optical fibers. And the
optical fiber itself is immune to these
geomagnetically induced currents because they
carry light and not electricity. But very
long cables have repeaters at 50 to 150 kilometer
intervals, which are connected in series and
powered by a conductor that runs along the length
of the cable. And this conductor is
susceptible to damages from induced currents. And
today, we don't have good failure models
to model the failure characteristics of long
cables. But the induced voltage across these
cables could be several magnitudes higher than
what the power system associated with
these cables are designed to handle. And today,
submarine cables have not been stress tested
under such large variations. So our long distance
cables are vulnerable. Internet routers, just
like data centers, can be protected from direct
voltage surges using voltage suppressors.
So they are safe. Now moving on to wireless
infrastructure, satellites at high altitudes
are directly exposed to these solar storms.
Typically, they generally have radiation shielding
for protection from high energy electrons.
However, very strong storms can cause electrons
to penetrate deep into the interior regions of a
satellite and damage its electronic components.
Solar storms can also cause drag on satellites,
which can lead to satellites losing their
orbit and re-entering the atmosphere and burning
up. So very recently, in February 2022, we
saw the news that 40 Starlink satellites were
lost to a geomagnetic storm. When a small
scale storm hit while the satellites were at
lower altitudes, while they were being
launched and before they were installed in their
high altitude orbits. So satellites
are known to be vulnerable to geomagnetic storms.
Cell towers are located at the ground
level and are protected from direct exposure by
the atmosphere. Similarly, personal devices
such as laptops and mobile phones are also safe.
So to summarize, long distance cables
and satellites are the most vulnerable components
of the internet. Other components could suffer
from power outages, but they're not susceptible
to direct damages. To understand the impact
on internet infrastructure, I looked at a broad
set of data sets comprising of various
internet components. The submarine cable map
consists of submarine cables across the globe.
The ITU cable map consists of land cable
information from across the globe collected by
various
regional entities. The InterTubes data set
includes long haul fiber cables in the United
States. And I also look at publicly available
internet exchange point location information
and DNS root server locations. And finally,
router locations with autonomous system mapping
obtained from Kaida was also analyzed. So now let's
look at some of the results. So
we know that higher latitudes are more vulnerable
to induced currents, particularly above 40
degree threshold. So we evaluate the distribution
of infrastructure components in this vulnerable
latitude region. So here we have the probability
density function across various latitudes
plotted on the x-axis. And we look at the
distribution of population as well as submarine
cable endpoints. So here we see that the
population is more concentrated on lower latitudes,
while
the infrastructure distribution is concentrated
at higher latitudes. And this shows that the
submarine cable endpoints, especially between the
US and Europe, are highly concentrated
at higher latitudes, which are more vulnerable.
And next we look at a variety of other internet
infrastructure components. So here we have again
the distribution across various latitudes.
On the x-axis, we have a latitude threshold. And
on the y-axis, we have concentration of
the infrastructure component above that threshold.
So here we look at internet routers, IXPs,
DNS root servers, and also the population. So the
most vulnerable region, again, is above
the 40 degree threshold. So that's towards the
left of the dotted line at 40. And here
we see that only about 16% of the world
population is in this region, but about 35% to 45%
of
the various internet infrastructure components is
in this vulnerable region. And this holds
for other components as well. You can find more
details in my paper. But the key takeaway
is that the internet infrastructure is skewed
towards more vulnerable regions when we consider
the threat of solar solar storms. Next, we look
at the cable length distribution. So
here on the x-axis, we have cable length in
kilometers in log scale. And this is a comparison
of CDFs of lengths of land cables and submarine
cables. And here the submarine data set is
complete. It consists of all existing submarine
cables that are currently active. The land
cables obtained from the ITU data set is not
complete, but it is the largest data set that
was publicly available. And here, only cables
that are longer than 150 kilometers needs
repeaters and hence need the conductor along the
length of the cable, which is vulnerable
to failures. So here we observe that more than 70%
of the cables on land don't need
repeaters and hence are not vulnerable to the
threat of induced currents. But only about
20% of submarine cables are shorter than this
threshold. So this means that nearly
80% of submarine cables need repeaters and hence
are susceptible to damages from induced
currents. In short, submarine cables are more
vulnerable than land cables under this threat.
I also conducted a repeater failure analysis
based on latitude-based failure models. So
there are several interesting observations. The
US faces a high risk of losing connectivity
to Europe during a solar superstorm. This is
because in the East Coast, most cables
between the US and Europe are concentrated
between the Northeast of the US and the UK,
which is most likely done for low latency. And
there are no connections from Florida
to Southern Europe, which would be less
vulnerable region. Fortunately, the cables
between Brazil
and Europe are less vulnerable. And it was also
surprising to find that the cable between
Brazil and Southern Europe is shorter than all
the cables between the US and Europe.
It's also located in the less vulnerable region
closer to the equator.
Looking at Asia, Singapore has a high chance of
retaining connectivity to neighboring countries,
even under severe storms. This is because the
cables are much shorter and also located
at lower latitudes, which are less vulnerable. So
this is the country-level connectivity
analysis. Next, we look at locations of public
data
centers across the globe. Here, red shows a
higher density, followed by orange, and
finally blue. We observe that data centers are
concentrated in vulnerable high-latitude
regions. And this observation also holds for hyperscale
providers such as Google, Facebook,
and Twitter. While these localized infrastructures
won't suffer direct damages, access to these
data centers can be affected. I also looked at
other internet infrastructure
components like domain name system. And with DNS,
root servers are highly distributed and
hence not vulnerable. And then autonomous systems,
a large fraction of autonomous systems
have a presence in vulnerable regions. But the
vast majority of ASS have a small spread.
And in the case of DNS servers, we only looked at
root servers. Location data of top-level
domain servers and other authoritative servers
was not available.
So these are some of the preliminary findings.
And so this work leaves more questions than
answers. So there is a lot of ongoing and future
work.
So this paper primarily looked at internet
partitioning based on submarine cables alone.
Now, understanding the impact on end-to-end
behavior of applications remained an open
challenge. So this needs to take into account
both land and submarine cables.
The primary analysis only looked at DNS root
servers. To understand availability, we need
to understand the distribution of the entire DNS
infrastructure, including the top-level
domain servers and authoritative servers, the
extent of caching in these servers, and
many other factors. Another interesting question
is, how will
AS level connectivity be affected by large-scale
network partitioning? And this needs AS level
connectivity analysis. Next, we need to, so in
order to robustify
the internet infrastructure, we need to devise
solutions for improving long-term resilience
of the infrastructure. So for example, this could
involve adding new cables in locations
that are less vulnerable. For example, between
the US and Europe, do we need a cable that's
further south to ensure resiliency? Another
interesting direction is design of
new inter-domain protocols that will improve path
diversity in the wide area network during
a disaster like a solar superstorm. Another very
useful feature of CMEs is that
it will reach the earth only 13 hours to 5 days
after it originates at the sun. So this
gives us a short interval to prepare for an
impact. And this is unlike disasters like,
for example, earthquake, where we have little to
no warning. This CMEs will give us 13 hours
to 5 days lead time. Now, how can we use this
lead time effectively?
We need to develop plans that will allow us to
prepare for an impact. How should data
centers react? What should internet services
service providers do? Do we need to increase
cache time of DNS entries? How should content
providers distribute data across different
data centers? If we know, if we have rough
estimates of probability of network partitioning.
And more broadly, we also need to rethink our
models of failure analysis. Current best
practices on fault tolerance and resilience
evaluation in software systems rely on failure
models that consider a limited number of failures.
We need to test our systems under large scale
failures and understand the behavior of our
protocols under large scale network partitioning.
Next, another interesting future direction is
related to reconnecting a partitioned internet.
After a solar superstorm, the internet may be
partitioned due to failures in long distance
cables or due to power outages in some regions
that could last days or weeks. So we need
to prepare with alternative solutions that can
provide temporary connectivity after impact.
So some examples could be internet connected
balloons or high altitude platform stations
that are mobile and typically deployed in the
stratosphere at heights of about 20 kilometers.
Ideally, they should rely on renewable power
sources such as solar energy to guarantee
connectivity even during power outages. So there
is some research in these areas, but
these are avenues that are worth exploring. And
finally, another very important factor
that we typically overlook today is the interdependence
of the internet with power grids. Now, both
internet and power grids are designated as
uniquely critical because all other critical
sectors rely on them. They are also interdependent
on each other and both are susceptible to
failures from solar superstorms. Hence, we need
to study the joint failure characteristics
on this complex interdependent system under solar
storms as well as other large scale
disasters. There are some interesting features
here because they have very different failure
characteristics. For example, in the US, there
are three regional power grids, the Eastern
Interconnection, Western Interconnection and the
Texas Interconnection. Now, if the power
grid in New York fails, it will only affect the
Eastern region and will not cause any
effects on the power grid in say, California,
which is on the west. The northeast will be
without power, but it's not possible to transfer
electricity from the west to the east because
these power grids are disconnected. Now, on the
other hand, if you look at internet connections,
if all internet connection to the east coast
fails, there'll be significant shifts in BDB
paths across the globe and potential overload in
network cables on the west coast. So, in
short, the internet is more global compared to
power grids and even regional failures
can result in significant consequences and churn
across the broader internet. So, understanding
their interdependency is an open question. So,
these are just a few of the open problems.
There are many, many more. So, with that, I'll
end the talk with a summary. So, space
weather, particularly coronal mass ejections from
the sun, poses significant risk to our
internet infrastructure. And the current
infrastructure has not been stress tested under
strong solar
events because modern technological advancement
coincided with the period of weak solar activity.
So, the complete extent of threat is yet to be
estimated. This is just the first work
in that direction. Internet infrastructure
components are currently skewed towards highly
vulnerable regions in the higher latitudes. So,
we need to think about improving the overall
end-to-end resilience. And at a high level, we
need to work towards better understanding
and improving the resilience of the global
internet infrastructure. Thank you. Thanks
for listening to my talk. And I'll be happy to
take questions after this.