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Re: maximum ipv4 bgp prefix length of /24 ?


From: Mark Tinka <mark@tinka.africa>
Date: Thu, 5 Oct 2023 08:55:11 +0200



On 10/5/23 08:32, Geoff Huston wrote:

Not really.

The stability of number in IPv4 as compared to the monotonic rise in IPv6 is what I find to be curious.

I think the fact that RIR's allocate very large IPv6 address space to their members may well be what is driving this.

Historically, network operators do enjoy de-aggregating address space. One can get significantly more /48's out of a /32 (or shorter) than they would /24's out of any IPv4 allocation they acquired.

One way to control this escalation is to shorten the maximum prefix length that all operators are willing to accept into the DFZ. The other way would be to get RIR's to lengthen the minimum allocation they can make to their members. Neither of these solutions is likely to be popular, but nor is having to pay large sums of money for more FIB.

Mark.

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