Customer AS

Henry Kilmer hank at
Mon Aug 19 11:59:57 UTC 1996

Sean Doran writes:
>Since March of 1995, Sprint has had contractual language
>with respect to our PA address delegations that make them
>explicitly non-portable, and not to be used in any other
>provider's network.
>In order to enforce that contract, we have installed
>inbound prefix filters to ignore all subnets of our PA 
>CIDR blocks that are announced by our peers at exchange 

This can be accomplished in many ways without preventing fallback
through another provider if one of Sprint's paying customers goes

>The simple solutions are, in order, 
>	-- make sure you have redundant connectivity to SL
>	   so that you do not lose connectivity to Sprintlink
>	   (admittedly we have not done a very good job
>           making this option attractive price-wise,
>	   unlike a pair of our competitors, however we
>	   are working on that, and hopefully this option
>	   will be attractive _notwithstanding_ our non-portability
>	   policy)

So they should buy two SL connections just so if one goes down they
still have connectivity?  If most multihomed customers were to the
same network, I would think that this idea was ok.  From my
experience, however, most multihomed customers have their second
connection to a different network.  Hopefully this will change but it
is reality for now.

>	-- work out mutual back-up transit with another
>	   dual-homed SL customer

This is difficult for some to do - particularly when they might be competing
with the other customers that might offer this type of backup transit.

>	-- offer yourself up as a PIARA-style volunteer

Most folks want better reliability when multihoming and would not go
for this idea at this time.  Most do not want to volunteer for anything
but rather have things just work.

>I would suggest that, far from indicating brain-damage
>at Sprint, our addressing and aggregating policies are
>rather clever.

One good thing they do is that once people become aware of them, they
make people think about multihoming.  Multihoming is more difficult
that it appears on the surface and most people enter into it rather


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