IPv6 route annoucement

Justin M. Streiner streiner at cluebyfour.org
Thu Aug 7 18:55:49 UTC 2014

On Thu, 7 Aug 2014, John York wrote:

> Hoping to not start a war...
> We (a multi-homed end-user site) are finally getting IPv6-enabled Internet
> connectivity from one of our ISPs. In conversations regarding our BGP
> config, the ISP has balked at allowing us to advertise our ARIN-assigned
> /44, saying things like, "do you know how many addresses that is!!??"

Sounds like the ISP in question is in need of some serious IPv6 clue.  The 
number of hosts means nothing, in terms of BGP advertisements.  In fact, 
fewer announcements is better.  De-aggregation bloats the global routing 

Most carriers I've seen will accept IPv6 announcements as small as a /48.

If your /44 was assigned by your RIR, and it's documented in their 
whois/rwhois/route registry, your ISP really doesn't have a leg to stand 
on, regarding not accepting your announcement.

> Am I way off base in thinking this network size is not out of the norm? I
> know it's a lot of addresses (19 octillion-something?), but that
> assignment was based on the same criteria that got us a /22 in v4 space.
> Should accepting a /44 in v6 not be equivalent, policy-wise, to accepting
> a /22 in v4?

The largest IPv6 prefix I saw in the global Internet routing table the 
last time I looked (a few months ago) that wasn't for a special purpose 
was a /19.... ~33 million times larger than a /44.

Your ISP should have more constructive things to do than hassling a 
customer about announcing a /44.


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