Multi-Homed Routing

Haesu haesu at
Tue Sep 2 10:03:04 PDT 2003


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

How is it that you need a "PORTABLE" /24 to announce it from your AS? I am talking stricly from experience here, this had been done, and is being continued to be done by many.

Huh????? Hard?? That's new. Even our good old friends at QWEST will off a /24 for BGP easily as long as request is justified.

The definition of portability is, the upstream holder of the IP you have is the organization that you received the IP from. If you quit buying service from that organization, and your assigned IPs are not portable, you have to return it back.

> > 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.

Legacy? Really? I see a lot of 69/8 prefixes that are /24's whether they are b/c networks don't know how to aggregate or b/c of legitimate traffic engineering or other reasons. And to mind you, 69/8 is the newest ARIN allocation from IANA.

Oh and also, a lot of countries in Asia-pacific regions do need to announce longer prefixes as they need to announce sub-prefixes in different locations due to expensive intra-AS and domestic circuits in their local market. This is no longer a legacy. Why is this discussion even happening at ARIN to allow prefixes longer than /20 to be allocated if this is legacy?

>   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.

We were just talking about routing table. You don't always get your IP's from ARIN or other RIR. You get it from your upstream. How hard is it to call up your upstream and say 'hey i need a /24 and here is my justification'? Not hard, unless you have issues with your provider. RIRs are there to help you if you need to get a direct allocation in larger quantity.


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

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

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