IPv4 smaller than /24 leasing?

[mh at xalto.net (Michael Hallgren)]

Le 2018-01-04 20:16, Job Snijders a écrit :
> On Thu, 4 Jan 2018 at 20:13, Filip Hruska <fhr at fhrnet.eu> wrote:
> 
>> I have stumbled upon this site [1] which seems to offer /27 IPv4 
>> leasing.
>> They also claim "All of our IPv4 address space can be used on any 
>> network
>> in any location."
>> 
>> I thought that the smallest prefix size one could get routed globally 
>> is
>> /24?
> 
> 
> Yes
> 
> So how does this work?
>> 
> Probably with GRE, IPIP or OpenVPN tunnels.
> 
> Kind regards,
> 
> Job

IPv4 /24 is commonly the minimal chunk advertised to (and accepted by) 
neighbors. If I run a global (or regional) network, I may advertise this 
/24 -- or rather an aggregate covering it -- over my diverse 
interconnection with neighbors, your /27 being part of the chunk and 
routed to you internally (if you're va customer)-- no need for 
encapsulation efforts. Similar scenario may be multi-upstream, subject 
to acceptance of "punching holes in aggregates"... Am I missing 
something? What's the trigger for doing tunneling here?

Happy New Year '18, by the way !

mh