[arin-ppml] Rationale for /22

[Michael K. Smith - Adhost]

> -----Original Message-----
> From: arin-ppml-bounces at arin.net [mailto:arin-ppml-bounces at arin.net] On
> Behalf Of Kevin Kargel
> Sent: Wednesday, July 29, 2009 10:49 AM
> To: William Herrin
> Cc: ARIN PPML
> Subject: Re: [arin-ppml] Rationale for /22
> 
> >
> > > I have dual
> > > homed customers who use IP's from me.  When I advertise those out
> my
> > > BGP portal they are aggregated.
> > >
> > > For example if I advertise 66.231.96.0/19 in my BGP and I have
> > > allocated
> > > 66.231.103.0/23 to one of my customers his network will be
> > > aggregated to
> > be
> > > within my BGP advertisements without adding a specific route.
> >
> > Then you would be making a mistake. His /23 announcement via the
> other
> > ISP will override your covering route, preventing him from receiving
> > any service from you whenever his other link is operational. The
> > more-specific route always overrides the less specific route.
> >
> > Regards,
> > Bill
> 
> Perhaps another factor that comes in to play here is that I do not
> accept advertisements for my own networks from external peers.  There
> is no need, I already know the best routes to my own networks.
> 
> Unless I am mistaken if one of my peers sends me my customers /23 route
> I believe that will trigger a rib failure and the route will not be
> injected in to my tables.
> 
> Whatever the mechanism I do receive the /23 advertisement.

I think it's more about what I see of your customer's routes.  If you announce a /20 and your customer via another provider announces a /23 I will always prefer that path.  So, my bits (and your revenue) will go to the other provider.

Mike