Multi-Homed Routing

Tom tom at
Tue Sep 2 09:56:32 PDT 2003

On Tue, 2 Sep 2003, Haesu wrote:

> Policy Proposal 2003-11 at ARIN may end up reducing from /20 to /22 for
> multihomed organizations.
> But regardless, getting a /24 is not hard. Ask your upstream. Your upstream provider assigns you a /24, not your regional RIR.
> Your RIR will only assign you on bigger needs, i.e. /20 as you said.

  Getting a portable /24 from your upstream is hard.  Even, then you end
likely end up annoucing a more specific prefix.

> Get on and see to yourself how many /24's are
> existing on internet routing table, not to mention how many of them are
> from North America, especially USA.

  Yes, there are a lot of /24's in the routing table.  That is legacy, and
if you look closely, many of those are pretty stupid too.  The policy
today, is that only small prefixes should be announced in order to prevent
route table bloat.

  In fact, I've seen a table on the ARIN site, which I can't find right
now, which shows the minimum block size that ARIN has assigned in each /8.
For instance, 204/8 the size was /24, and for 216/8, it was /20.  A lot of
networks use these rules to build a routing policy to block bogus routes.
It keeps the legacy junk routes contained.

> -hc
> --
> Sincerely,
>   Haesu C.
>   TowardEX Technologies, Inc.
>   WWW:
>   E-mail: haesu at
>   Cell: (978) 394-2867


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