BCP for multisite multihoming

[Kevin Day]

On May 21, 2007, at 2:19 PM, Leo Vegoda wrote:

> On 21 May 2007, at 3:04pm, Kevin Day wrote:
>> 2) This company requires IP addresses for internal use, customer  
>> use, etc.
>
> At the point you say that they will be assigning address space to a  
> customer they become an ISP, I suppose.
>

I was trying to be general/vague enough to keep it slightly blurry  
between an ISP or end user. But sure, ISP it is.

>> 7) There is no connectivity between each POP at all, everything  
>> between nodes goes over the internet.
>
> This seem to be four separate ISPs, in four separate continents  
> that just happen to be owned by a single organisation and possibly  
> share a brand.
>

That's one way of looking at it, sure.

>> 4) Obtain multiple /32s, announce one from each POP.
>>
>> Probably not possible - The bar is pretty high to receive a  
>> second /32, most companies will never reach the utilization  
>> percentage to receive a second, let alone one per POP.
>
> Presumably this company is incorporated in each country in which it  
> has a PoP. It is effectively four companies with a common owner. As  
> such, I think #4 is the right answer and I don't think it should be  
> too difficult to get the address space.
>


In the specific company I'm thinking of when proposing this, no,  
that's not true.

Or forget the fact that they're in separate companies, pretend it's  
one company within the US that has a dozen branch offices within the  
US. Or a hosting/colo/access company with cages in a dozen  
datacenters. Or.. whatever. :)


>
>> * If these four offices were multiple companies instead of owned  
>> by the same, they'd have no problem obtaining space and announcing  
>> their own space at each POP. It would also equal the same number  
>> of routes in the table as if the one company had just  
>> deaggregated. Things are being complicated because they're owned  
>> by the same legal entity. One legal entity doesn't necessarily  
>> equal one unique network though.
>
> Bingo!


Okay, if that's the approach you recommend, then sure. But:

Having an entire /32 per POP is tremendous overkill. And, it's still  
using just as many routes as if this company could just deaggregate  
the prefix it received. I'm also assuming that additional prefixes  
aren't going to be free, which is going to further add to the  
operating expenses of v6 over v4. It also means the company isn't  
able to tailor its space usage to each POP.

Is one allocation/assignment per site really scalable?

-- Kevin