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Re: more specific routes in today reality

  • To: "Vladimir A. Jakovenko" < >
  • From: Gert Doering < >
  • Date: Tue, 9 Oct 2001 15:23:30 +0200
  • Cc: Gert Doering < >

Hi,

On Tue, Oct 09, 2001 at 04:02:08PM +0300, Vladimir A. Jakovenko wrote:
> >>        1. Routes with more than one origin.
> >
> >No - the more specifics are announced by the customer AS *only* (and the
> >upstream AS that this blocks belongs to will permit them "through").
> 
> We are talking about different types of multihoming. I mean simple multihoming 
> situation when all multihomed customer's needs in routing are covered by they
> upstream providers routing policies. In this situation more specific PA route 
> can be originated by upstreams without allocation to customer new AS-num.
> Moreover, according to ripe-185:
> 
>    In order to help decrease global routing complexity, a new AS Number
>    should be created only if a new routing policy is required.

I didn't realize this, but I agree with Randy on this: without their
own AS number (and with them doing the BGP origination stuff and so
on), this isn't going to work anyway - if they do not want to do BGP,
then they should multi-home to the *same* ISP.

[..]
> > - if one is filtering "no /24's", the end site is *still* be reachable,
> >   which would not work with PI space.
> 
> Disagree. During last time a number of routing curioses at least in our country
> have been caused by incorect announcements or filtering more specific routes 
> within already announced less specific routes. If you want, I can describe some
> of the most common problems. PI addresses have its own set of problems, more 
> specific PA addresses also have own set problems. This sets partly overlaps,
> but not same. And PA more specific isn't safer than PI. They just unsafe a bit
> more different.

They will be much safer when people start filtering out "long prefixes".

Which will happen *soon*.

Gert Doering
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