RE: geo short vs long term? [Re: Geo pros and cons]

["Christian Huitema" <huitema@windows.microsoft.com>]

Tony,

There are a few issues with your maths. 

First, the 100% per year figure relates to the traffic growth, not the
growth in the number of hosts. The number of hosts does grow, but not
nearly as fast. The host count measured by the Internet domain survey
grew 20% last year, but that does not account for hosts behind NAT. If
you assume that the traffic growth is caused equally by larger pipes and
by more devices, then you get a growth in the number of hosts of about
40% per year.

Second, the number of sites does not grow at the same pace as the number
of hosts. For example, the number of PC per household or per office is
increasing. The hypothetical 40% host grow could be split between a
growth in the number of connected sites (new homes, new offices) and a
growth in the number of hosts per site. This would result in a 20%
yearly growth for the number of sites.

Most of the sites being added are small sites, which are the least
likely to be multihomed -- the big sites are already connected, probably
already multihomed. So, there is a strong case that the 10% figure is
probably an overstatement. But let's keep it.

The cost of maintaining the routing tables is somewhere between O(N.log
N) and O(N^2). Given the current size of 100,000 entries, a 20% increase
would correspond to an increase of 22% to 44%. 

Moore's law corresponds to an increase of about 60% yearly. 60% beats
22%, or even 44%. There is no reason to panic.

There is also no particular reason to love geographic addresses, but
that is another issue.

-- Christian Huitema

> -----Original Message-----
> From: Tony Li [mailto:Tony.Li@procket.com]
> Sent: Thursday, April 03, 2003 12:10 PM
> To: J. Noel Chiappa; multi6@ops.ietf.org
> 
> 
> 
> Noel, well said.
> 
> More points: there are worse things than no decision.  That
> would be the clearly wrong decision.  We could, for example,
> choose to aggregate locators based on the lexographical
> ordering of the user's first name.  We could choose not to
> aggregate and end up with another swamp.
> 
> As to the issues with 'proving' that geo won't work, let me
> point out the very simple reasoning:
> 
> - The Internet is continually growing at an exponential rate.
>   Most people seem to peg the growth rate at 100% per year
>   currently.  The exact number is not an issue.
> 
> - In the past, we've estimated that 10% of all sites would
>   multi-home.  Let's assume a constant rate of 10% of the
>   world is an exception to the default aggregation rules
>   that we pick.
> 
> - From the above two, we can reason that our exception rate
>   is going to continue to grow exponentially.  Note that
>   the rate of absolute growth is more of an issue than the
>   exception rate.
> 
> - Moore's law for memory suggests that memory sizes will
>   double about every two years.  However, memory speeds will
>   not keep up.
> 
> - Packet lookups are a function of memory bandwidth, so to
>   sustain Internet bandwidth growth of 100% per year, we need
>   to also increase memory bandwidth by about 100% per year.
>   Using bigger, slower memories is not a realistic option.
> 
> - Thus, the routing table really needs to be constrained to
>   grow at about Moore's law for memory.
> 
> - If the exceptions are growing at about 100% per year, and
>   the memories are growing at about 100% every TWO years, then
>   regardless of the starting point, the exceptions will overtake
>   technology.
> 
> - Therefore, we must find some mechanism that prevents the
>   exceptions from growing at 100% per year.  In short, the
>   number of longer prefixes that are injected into routing
>   cannot be a constant fraction of the number of sites that
>   join.
> 
> - Since everyone and their brother will want an exception
>   for anything that they want to do that is outside of the
>   norm, the norm MUST support almost every possible situation.
>   Multihoming, in particular, must not cause exceptions.
>   Even a constant percentage of multihomers must not cause
>   exceptions.
> 
> - For reasons that I've already explained, the economics
>   of links in a geo system cause many sites to be exceptions.
> 
> - Therefore, geo addressing leads to a system that will not
>   scale for the long term.
> 
> QED
> 
> Tony
> 
> 
> |    -----Original Message-----
> |    From: J. Noel Chiappa [mailto:jnc@ginger.lcs.mit.edu]
> |    Sent: Thursday, April 03, 2003 4:38 AM
> |    To: multi6@ops.ietf.org
> |    Cc: jnc@ginger.lcs.mit.edu
> |    Subject: Re: geo short vs long term? [Re: Geo pros and cons]
> |
> |
> |    Look, everyone, this is all really stupid.
> |
> |    Geographic addressing has been discussed extensively about
> |    17 times in the
> |    IETF, and every time it has been rejected. Discussing it
> |    one more time is not
> |    going to change this. There is *never* going to be a rough
> |    consensus *in
> |    favour of* geographic addressing. There will *always* be a
> |    lot of people
> |    against it - enough to stop it in the proposal stage.
> |
> |    The really sad thing is that something productive might
> |    have been done with
> |    all this time and energy that's being wasted.
> |
> |    	Noel
> |
> |
>