So in this series we're going to look at
internet exchange points and what value
they bring to the internet ecosystem.
So let's start at the beginning.
Consider a region with one Internet
service provider. They're providing
Internet connectivity to the customers
and they have one or two international
or transit connections as linterna grows
another isp sets up in competition they
provide internet connectivity to their
customers and they also have transit
connections so how does traffic from one
customer of one ISP get to a customer of
the other ISP yes indeed the transit
connections and these quite often would
be international links going out of the
country to some backbone provider in
another country or even another part of
the world major contact maybe tens if
not hundreds of milliseconds away if
this link is over satellite the
round-trip time would be 550
milliseconds per hop if we're using
geostationary satellites so local
traffic between two operators could take
over one second round-trip time and this
is a huge disincentive for a local
internet economy why would say a local
newspaper or television station who is
content with one ISP if half the
customers in the country are connected
to the other ISP they'll be much better
off hosting their content with the
transit provider of the two ISPs in
another country somewhere else on the
planet and this also means international
bandwidth and that cost significantly
more than domestic bandwidth it will be
congested than with local traffic local
traffic on international links waste
money for both operators and harms
overall performance for all users so the
solution of this is that the two
competing ISPs peer with each other
maybe an unusual solution and certainly
the two competitors would not like the
idea of somehow cooperating with each
other but it is actually the best and
only solution to this issue the result
is that both operators save money local
traffic stays local thus better network
performance better quality of service
and more international bandwidth for
expensive international traffic and
everyone is happy what happens now when
a third ISP enters the equation they
become a significant player as well and
we see the same thing local and
international traffic goes over the
international connections all 3 ISPs
agree to peer with each other to save
money keep all go traffic local improve
network performance improve service
quality for end-users
improve the value proposition for local
content hosting private peering means
that the 3 ISPs have to buy circuits
between each other
it works for 3 ISPs by adding a fourth
or a fifth means this does not scale and
the solution is the internet exchange
part internet exchange point is where
each participant has to deploy just one
link from their premises to the IXP
rather than n minus 1 links to connect
to the N minus 1 other ISPs 5 ISPs will
have to share the cost of 4 links which
is to whole links and that's already
twice the cost of simply going to the
exchange part so the solution is that
every ISP participates in exchange point
the cost is minimal one link covers all
domestic traffic and international links
are now used just for international
traffic and of course backup of the
domestic links in case the IXP suffers
any outage the result local traffic
stays local QoS considerations for local
traffic is simply not an issue and the
round-trip times between members are
typically under a millisecond customers
enjoy the internet experience and the
local internet economy
grows rapidly so who can join an IXP
well the requirements are actually very
simple any organization which operates
their own autonomous network and has the
own address space their own a s number
and their own transit arrangements it
really is as simple as that so this
includes commercial ISPs it includes
academic and research networks it
includes Internet infrastructure
operators for example the root name
server operators the country top level
domain operators and the general
top-level domain operators content
providers and content distribution
services quite often turn up at exchange
points as well broadcasters in the media
and of course with more and more
government appearing in many countries
around the world government information
networks quite commonly will join
exchange points as well there are times
when an exchange point may not be
beneficial it may be by legislation
where there's one legislative monopoly
transit provider with all other network
operators are legislated to be customers
of this monopoly provider there's not
much that can be done here apart from
change in the legislation an IXP may not
be beneficial due to geography when the
local economy is so small that it cannot
sustain more than one network operator
very small nations are sparsely
populated or remote areas there may be
cases where an exchange point is not
permitted and this is still the
situation in several countries around
the world
usually it is a government owned
operated national telco where the isp
license mandates connecting to the
national telekinetic ations of this are
expensive domestic connectivity because
the national telco can set whatever
price they want
can be expensive international
connectivity because the national telco
doesn't feel the need for any
competition or any competitive prices
and they can pass on whatever costs they want.
Restricted and poor service offerings.
No one's competing with them, no one
has any incentive to be creative
and there is generally
no domestic internet economy.
Everyone loses especially the national telco
who's trying to stop the
competition in the first place.
© Produced by Philip Smith and the Network Startup Resource Center, through the University of Oregon.
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