maximum ipv4 bgp prefix length of /24 ?

Willy Manga mangawilly at gmail.com
Sat Oct 7 12:32:31 UTC 2023


Hi.

On 06/10/2023 16:00, nanog-request at nanog.org wrote:
> From: Matthew Petach<mpetach at netflight.com>
>[...]
>> The IPv6 FIB is under the same pressure from more specifics. Its taken 20
>> years to get there, but the IPv6 FIB is now looking stable at 60% opf the
>> total FIB size [2]. For me, thats a very surprising outcome in an
>> essentially unmanaged system.
>>
>>
>> Were you expecting it to be lower than IPv4?
>>
>> Mark.
>>
> I've dug through the mailman mirror on nanog.org, and there's currently no
> post by Geoff Huston saying that:
> https://community.nanog.org/search?q=geoff%20huston%20order%3Alatest

I read (and send) NANOG emails through the digest emails sent once a 
day. I noticed the same thing . I assumed it was sent directly to Mark 
(or the mail will enter my next digest...)


> But I'll play along.
> 
> There's significantly less pressure to deaggregate IPv6 space right now,
> because we don't see many attacks on IPv6 number resources.
> Once we start to see v6 prefix hijackings, /48s being announced over /32
> prefixes to pull traffic, then I think we'll see IPv6 deaggregation
> completely swamp IPv4 deaggregation.

How about we educate each other to not assume you must deaggregate your 
prefix especially with IPv6?

I see 'some' (it's highly relative) networks on IPv4, they 'believe' 
they have to advertise every single /24 they have. And when they start 
with IPv6, they replicate the same mindset with a tons of /48 . You can 
imagine what will happen of course.

A better alternative IMHO is to take advantage to the large prefix range 
and advertise a sub-aggregate when necessary. But absolutely not each 
end-node or customer prefix.


-- 
Willy Manga
@ongolaboy
https://ongola.blogspot.com/
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