RE: Geo pros and cons

["Tony Li" <Tony.Li@procket.com>]

Iljitsch,

|    Now obviously it is possible to lease a circuit to a 
|    remote location 
|    and connect to "the internet" in that location rather than 
|    close to 
|    home. But should we consider this a feature we must 
|    support, or is it 
|    an exceptional situation that we can safely ignore?


Since this happens all too frequently, we must deal with it.  The
Internet is not a centrally run function.  Instead it grows
organically by the needs of the users.  In other words, the links
only show up where they make economic sense.  And those are the
links that users will use, ignoring the consequences.

    
|    Since the scalability of geographical aggregation depends 
|    on the number 
|    of internet users and the size of the aggregation areas, 
|    where each 
|    aggregation area needs at least two interconnects, it 
|    would seem that 
|    the scalability of geographical multihoming isn't a problem: more 
|    multihomers means more routes in an area, but since more end-users 
|    means more interconnects, the areas shrink. So the number 
|    of routes per 
|    area should remain fairly constant.


If the routes are proportional to the number of areas and the areas
are growing, then you again have a rapidly growing routing table.

As we concluded many years ago: for addressing to scale, it has
to match the topology.  If addressing does not match the topology,
then additional information in the form of longer prefixes must be
advertised into the routing subsystem.  Ergo, if one chooses geographic
address, one must force only geographically based links.  Anything
else destroys the aggregatability of the address assignment.  Since
we, as IETF members, cannot decree where folks will connect, geo 
addressing is a nice theorectical goal which is unimplementable.

Regards,
Tony