Hi Bill,
thank you for this great explanation.
> On 18. Jan 2024, at 23:38, Bill Woodcock via Nnagain
> <nnagain@lists.bufferbloat.net> wrote:
>
>> On Jan 18, 2024, at 22:51, le berger des photons via Nnagain
>> <nnagain@lists.bufferbloat.net> wrote:
>> First I've ever seen the term IXP. It seems interesting. Can you point me
>> to some documentation at a level which only requires the ability to read in
>> english? Lots of what I've seen here has initials for things which I
>> haven't even been able to decode.
>> I've been connecting 200 families in a 25 km radius to internet via 8 fiber
>> optic connections for the last 20 years.
>> I've been thinking of inviting others to participate, help them get going.
>> Thinking how it might be useful to provide each client two accesses. one to
>> the global internet, one to a local network which isn't being watched by
>> big brother.
>> Does any of this warrant my looking further into IXP technology?
>
> Hi, Jay.
>
> I’m afraid I’m really bad at getting all this stuff written down, though I
> know it would be useful. I am planning to write a doctoral thesis on exactly
> this topic (the societal and economic impact of Internet exchange points) for
> Universite Paris 8 next year, but that will need to be a bit more academic
> than practical, to satisfy, you know, academia.
>
> So, really basically, it sounds like you’re already building an internet
> exchange. Internet exchanges are where Internet bandwidth comes from.
> Internet service providers bring Internet bandwidth from IXPs to the places
> where people want to use it: their homes, their offices, their phones.
> Internet bandwidth is free _at_ the exchange, but transport costs money.
> Speed times distance equals cost. So the cost of Internet bandwidth is
> proportional to the speed and the distance from IXPs. Plus a profit margin
> for the Internet service provider.
>
> So, if one Internet user wants to talk to another Internet user, generally
> they hand off their packet to an Internet service provider, who takes it to
> an exchange, and hands it off to another Internet service provider, who
> delivers it to the second user. When the second user wants to reply, the
> process is reversed, but the two Internet service providers may choose a
> different exchange for the hand-off: since each is economically incentivized
> to carry the traffic the shortest possible distance (to minimize cost, speed
> x distance = cost), the first ISP will always choose the IXP that’s nearest
> the first user, for the hand-off, leaving the second ISP a longer distance to
> carry the packet. Then, when their situations are reversed, the second ISP
> will choose the IXP nearest the second user, leaving the first ISP to carry
> the packet a longer distance.
> [...]
I would propose a slight modification, "each is economically incentivized to
carry the traffic the shortest possible distance" is not free of assumptions...
namely that the shortest path is the cheapest path, which is not universally
true. My personal take is "routing follows cost" that is it is money in the end
that steers routing decisions not distance... (sure often shortest is also
cheapest, but it is simply not guaranteed, at least once we include paid
peering and transit into the equation). Most end-users would actually prefer
shortest distance...
Case in point, my ISP aggregates its customers in a handful of locations in
Germany, Hamburg in my case while I actually live a bit closer to Frankfurt
than Hamburg, so all traffic first goes to Hamburg even traffic to Frankfurt
(resulting in a 500-600 Km detour), I assume they do this for economic reasons
and not just out of spite ;)
Now, maybe the important point is, this does not involve IXPs so might be an
orange to the IXP apple?
Regards & Thanks again
Sebastian
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