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Re: [RRG] Mobility considerations in proposal evaluation

On 27 feb 2008, at 19:45, William Herrin wrote:


Lets step outside the box for a moment. Suppose we organize our
network by hostname instead of by network address? We don't want to
lose any of the hostname's functionality when we do this; the hostname
should still be a logical organization outside the scope of the
network location. So we aren't going to route by hostname; we'll still
have some sort of address under the hood.
In theory, we have that. But people still care way too much about addresses to change them whenever the routing system needs them to be changed. Most important reason for this is firewalls. When filtering, you really need to have something to filter on in every packet. Which means you filter on the address, not on the hostname, because the hostname isn't in the packet. 


Lets do two things to the network address:



1. Let's make it strictly ephemeral. It can change at any time, even
in the middle of communications. Only the hostname is sure to stay the
same.


Been there, done that: shim6, MIP.
People simply refuse to let go of their (provider independent) addresses. We could of course declare the problem solved and if people don't want to use the solution, that's their choice but not our problem. Especially not for those of us making a living from selling bigger and bigger boxes.
But I guess we're not doing that otherwise we wouldn't be having this discussion. 


The most critical problem with all this is that we'd have to rip out
and replace the guts of the Internet to attempt it. Like with IPv6,
this system would have to operate dual-stack for a decade.
Replacing a lot of stuff doesn't automatically mean it has to take a decade. The reason that IPv6 is so difficult is because EVERYTHING touches IP addresses, and you need to update the entire chain before you can use the new type of addresses, including applications, which have eternal life. Only a million or so boxes do inter-domain routing, and I've never heard of anyone using 10 year old software on those boxes in production. 


For better or for worse, IPv4 bounds the box we're stuck with.
The endgame for IPv4 is about to start. No point wasting time on IPv4- specific solutions. 


Is there anything else? Do you have an inkling what it might look
like? I'd hate for history to look back and say we suffered a failure
of imagination but it's also possible that there isn't a fourth avenue
to explore that's achievable from where we are today.
Maybe this would be a good point to start up the biannual geographic routing discussion again. 


Alternatives? Information theory has some useful things to say about
information flow but the last I heard there are really only five ways
to get information:



1. You're told (unsolicited).
2. You seek and find out (solicited).
What about: the holder of the information tells a third party, the party needing the information asks the third party = a rendezvous point.
Note that you can't see and find out routing information from the source, because you need to know how to talk to the source to do that, and the routing information is exactly what lets you do that.
Of course this can be solved with an overlay network a la ALT but I see a number of downsides there. 


Perhaps the Angelic Routing Protocol where at each router the packet
briefly stops and prays for guidance. Loss only occurs when packets of
insufficient faith are tempted down the wrong path.


:-)


Verily I tell
thee, all DFZ scalability problems can be solved with with ARP.
Sure, right after we solve the inter-domain broadcast scalability problem. 

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