Draining the Swamp, A Straw Proposal

Sean Shapira sds at jazzie.com
Tue Jan 30 04:56:40 UTC 1996


There have been several suggestions on the nanog list recently 
about ways to clean up the IP address "swamps" created by prior, 
piecemeal allocations of class C addresses.  I understand the 
PIER Working Group of the IETF, with the approval of the IANA 
and Internic, are currently surveying those swamps to provide
data for evaluating proposed solutions.

Before making addtional proposals one might then do well to 
ask, "What criteria should a 'good' solution meet?"  Here's 
my list:

  - Impose few administrative costs on end users.  Approaches 
    involving renumbering or installing IP tunnels won't meet 
    this criterion until much better tools are available.

  - Depend only on voluntary participation by Internet providers.  

  - Gain for participating providers smaller route tables.

  - Assure that no customer of a provider is unduly harmed by 
    the provider's participation.

Can a solution be found that includes all these criteria?  Perhaps 
not, but here's a "straw" proposal nonetheless.


Participating providers divide a swamp into sections.  For 
example, four providers could divide 192/8 into 192.0/10, 
192.64/10, 192.128/10, and 192.196/10.  

Each provider continues to announce its customer /24 routes, but 
in addition each announces to the others one of the four /10 routes.
For the /10 route which it announces, each provider accepts and 
keeps all the /24 routes it hears.  For the other three, it keeps 
only the /10 route and filters out any /24 routes it hears.

The resulting routing might be inefficient:  provider A might
deliver packets to provider B that are eventually destined for
a customer of provider C.  But packets do continue to reach
their ultimate destinations.

Providers get smaller route tables, while customers remain 
blissfully unaware (and thus continue to pay for service ;-).

Note that four is not a magic number:  any two providers could 
bilaterally enter into an agreement of this type and get reduced 
route table sizes.

Personal Note:

As an observer on the sidelines of nanog activity, I certainly
lack the experience of the "older, wiser heads" who operate the 
major providers' backbone networks.  Those with that experience,
and the knowledge accrued therefrom, may well find gaping holes
in this straw proposal.  I look forward to their criticism,
either in traffic on the list, in private email, or in person
at the upcoming San Diego meeting.

Sean Shapira         sds at jazzie.com         +1 206 443 2028
 <a href="http://www.jazzie.com/sds/">Sean's Home Page</a> 
               Serving the Net since 1990.                 

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