History of 4.2.2.2. What's the story?

Joe Abley jabley at hopcount.ca
Sun Feb 14 17:04:46 CST 2010


On 2010-02-14, at 17:43, Mark Andrews <marka at isc.org> wrote:

> Using three consecutive addresses doesn't remove
> single points of failure in the routing system.

That depends on how the routes for those destinations are chosen, and  
what routing system you're talking about.

For distribution of a service using anycast inside a single AS, and  
with one route per service, it makes no difference whether the  
addresses are adjacent. Two /24 routes are no more stable than two /32  
routes within an IGP. There's no prefix filtering convention to  
accommodate, here.

>
>> If their goal is distribute a service for the benefit of their own =
>> customers, then keeping all anycast nodes associated with that  
>> service =
>> on-net seems entirely sensible.
>
> Which only helps if *all* customers of those servers are also on net.

Whether it helps depends on what Level3's goals are. This is not  
public infrastructure; this is a service operated by a commercial  
company.

For what it's worth, I have never heard of an ISP, big or small,  
deciding to place resolvers used by their customers in someone else's  
network. Perhaps I just need to get out more.


Joe




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