Re: Newbie Question about addressing impacts

[marcelo bagnulo braun <marcelo@it.uc3m.es>]

El 12/08/2004, a las 12:12, Tony Li escribió:

> > > Ideally, in an Internet architecture that we don't have today, there 
> > > would be N prefixes, one per ISP.  However, the host
> > > portion of the locator would be a constant regardless of prefix.  
> > > The IGP need not know about the external prefixes, so there's
> > > no issue there.
> >
> > Good point.
> >
> > But this implies modifying IGPs, right?
>
>
> Not seriously.  You would be modifying them to carry around a constant 
> local portion of the address and ignore the "global"
> prefix.  Simply picking a single constant prefix for use internally 
> would suffice.

so are you assuming that hosts within the multihomed site are not aware 
of their own global prefixes, so they only use this local prefix and 
that global prefixes are stuffed by exit routers "a la" GSE?

I was more thinking in that hosts are aware of their own global 
prefixes and that they use them within the site, but intr site routers 
know which are the local prefixes, so when the see a destination 
address that contains one of them, it just ignores the global part 
(/48) and just routes according to the bits between the /48 and the 
/64.
this implies that router have to know which are the global prefixes 
assigned to the site and for that case route based on the subnet bits.
(that is why i thought that some change to the intra site routing was 
needed)
regards, marcelo

> Tony