Re: [address-policy-wg] Questions on Provider Independent IPv4 addresses,

[Gert Doering <]

Hi,

On Fri, Oct 17, 2003 at 10:56:51AM +0200, Thomas.Levy@localhost wrote:
> 1) Usage of PI addresses is not recommended by RIPE. I don't want to 
> raise a debate on this point. However, I would be interested in knowing 
> the reasons for this. Is it for routing purpose?

One of the major disadvantages of PI space to achieve global internet
connectivity is "impact on global routing".

Especially for networks needing only fairly few addresses, using
addresses from their ISP's PA network blocks means that their route
can be aggregated into the ISP's PA route, so the individual network
doesn't have an impact on all routers world-wide that carry the full
IPv4 routing table.

A PI network will always be visible as an individual route, with no
way to aggregate it.

Of course PI has advantages (it's much more convenient for the 
enterprise in question) and in some cases there is no way around PI
(enterprise-local networks that are not connected to any ISP but
need unique address space for VPN partner connections etc.).

Gert Doering
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