[arin-ppml] Rationale for /22

David Farmer farmer at umn.edu
Mon Aug 3 14:01:38 EDT 2009

On 3 Aug 2009 Kevin Kargel wrote:

> One quick point on the existance or emergence of small multi-homed
> networks..
> In the past year and a half I have seen a very noticeable increase in the
> number of small organizations that are going or attempting to go multi-homed
> with DSL connections to multiple upstream providers.  They are doing this as
> a means to try and do what they did before with expensive dedicated circuits
> like T1.  Increased reliability of a $39.95 SDSL has led these customers
> down the primrose path to think that if they have a couple of these then
> they don't need an $800 ATM circuit.  
> I am not saying I agree with this philosophy or even that I think it is
> functional, but I am seeing it happen.
> As these customers get educated they figure out that they are technically
> "multi-homed" and that they "can" get their own IP space, and if they invest
> in a router that can do BGP they can gain transparent (to the end user)
> routing reliability using these DSL connections.  Bean counters tend to
> prefer non-recurring expenditures to recurring expenditures.  
> These organizations are small hospitals, clinics, small banks, farmers,
> insurance agencies, non-chain manufacturers and distributers, et.al.  They
> don't need a lot of IP, but they do need routing failover.  They are
> learning that it is theoretically (albeit not realistically) possible to do
> what used to require a T1 on SDSL better for a fraction of the cost.  
> I believe we will see a mushrooming incidence of these small multi-homed
> organizations in the routing tables in the coming years.  
> This will affect the issue of global routing table size and does have a
> bearing on reducing the minimum allocation unit.  

This is exactly the situation that providing PI /24s could create 
the inducement for many more users to multihome that I was 
refering to and then create the tipping point Leo was refering 

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.

As I said I'm not sure how to set this up legaly and we would 
probablly need ARIN policy to enable it, as I beieve it would 
probablly violate one or two policies.

As I don't work for an ISP, I'm not sure this could work from a 
business model point of view either.  It would definitely take a 
set of ISP with an enlightened view of competition to make it 

Could something like this work?  

I'm sure I'm missing one or two details.  But, at least Kevin's 
anecdote makes me think there could be a market for such a 
service.  And with this kind of a solution end-users could 
multihome down to a /28 or /29 without creating minutia in the 
global route table.

David Farmer                                      Email:farmer at umn.edu
Office of Information Technology
Networking & Telecomunication Services
University of Minnesota		       Phone: 612-626-0815
2218 University Ave SE		       Cell: 612-812-9952
Minneapolis, MN 55414-3029	       FAX: 612-626-1818

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