aggregate6 - a fast versatile prefix list compressor

Fri Dec 1 10:16:37 UTC 2017

nanog at studio442.com.au (Julien Goodwin) wrote:

> > The first optimisation is to remove any supplied prefixes which are
> > superfluous because they are already included in another supplied
> > prefix. For example, 2001:67c:208c:10::/64 would be removed if
> > 2001:67c:208c::/48 was also supplied.
> > 
> > The second optimisation identifies adjacent prefixes that can be
> > combined under a single, shorter-length prefix. For example,
> > 2001:67c:208c::/48 and 2001:67c:208d::/48 can be combined into the
> > single prefix 2001:67c:208c::/47. As an IPv4 exampl: 10.0.0.0/24 and
> > 10.0.1.0/24 can be joined into 10.0.0.0/23.
> 
> Will it catch cases like:
> 10.0.0.0/24 10.0.1.0/24 10.0.2.0/23 -> 10.0.0.0/22

I guess the developers will have implemented a loop that runs until no
more optimizations have been found. Which would of course catch it as

Iteration 1
10.0.0.0/24 + 10.0.1.0/24
-> 10.0.0.0/23

Iteration 2
10.0.0.0/23 + 10.0.2.0/23
-> 10.0.0.0/22