keeping the routing table in check: step 1

["Edward B. DREGER" <eddy+public+spam () noc everquick net>]

Hopefully this thread will be quick and less convoluted.  Rather than 
simply alluding to "one prefix per ASN", I'd like to detail an 
allocation scheme that works toward that.

Find the largest contiguous block.  Split in half.  Round to appropriate 
boundary.  Assign.  Space at the end of the block is reserved for 
expansion.

Ignoring special subnets for simplicity:

0/x, 128/x,
64/x, 192/x,
32/x, 96/x, 160/x, 224/x,
16/x, 48/x, 80/x, 112/x, 144/x, 176/x, 208/x

assuming all grow at equal rates.  96/x ends up growing quickly?  No 
problem.  Skip 112/x for the time being.

In short, allocate IP space logarithmically.  Start with /1 alignment, 
proceed to /2, then /3, and so on.  Keep the array as sparse as possible 
so an assignment can be extended without hitting, say, a stride 4 
boundary.

Perhaps RIRs should look at filesystems for some hints.  Imagine a 
filesystem that's 30% full yet has as much fragmentation as IPv4 space. 
Something is wrong.


Eddy
--
Everquick Internet - http://www.everquick.net/
A division of Brotsman & Dreger, Inc. - http://www.brotsman.com/
Bandwidth, consulting, e-commerce, hosting, and network building
Phone: +1 785 865 5885 Lawrence and [inter]national
Phone: +1 316 794 8922 Wichita
________________________________________________________________________
DO NOT send mail to the following addresses:
davidc () brics com -*- jfconmaapaq () intc net -*- sam () everquick net
Sending mail to spambait addresses is a great way to get blocked.
Ditto for broken OOO autoresponders and foolish AV software backscatter.