[arin-ppml] Rationale for /22

[michael.dillon at bt.com]

> Thinking a little out side the box here and I'm not even sure 
> something like this would be legal, it might be considered 
> colluding.  What if a pair of providers or maybe even a set 
> of providers were to jointly obtain a block of addresses to 
> allow customers to multihome.  Customers would connect to two 
> or more participating providers, announce there block to the 
> providers and then the providers contain the customer 
> announcements within there joint infrastructure and only 
> announce the aggeraget to the Internet.

No need to "jointly obtain" addresses. The two ISPs just need
to agree to use a block from one of their allocations and to
maintain direct peering links with sufficient bandwidth to 
handle the failover traffic.

When I was with Ebone back in 2000 we arranged this for a major
customer who wanted to have a backup ISP but did not want to
be responsible for managing multihoming. From the business 
point of view they wanted ONE provider and that was Ebone. But
they wanted Ebone to buy and managed multihomed connectivity 
to another major ISP. Since Ebone was supposed to be fully managing
the solution, we couldn't register a PI block in their name, but
had to use a chunk of our own space and get another ISP to announce
that chunk as well.

--Michael Dillon