North American Network Operators Group

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Re: Confussion over multi-homing

  • From: Austin Schutz
  • Date: Fri Sep 15 03:51:20 2000

> > Yep, this has been a topic here real resolution. You didn't
> > really need to prove the case, it has already been proven.
> No.  From a post I made to this list on 6/22/2000:
> ++> Here's the deal.  If you number out of Provider1's CIDR block
> ++> but advertise your more-specific to Provider2 and the two Providers
> ++> touch and Provider1 accepts the more-specific route from Provider2,
> ++> you should have no problem reaching anyone.
> ++> 
> ++> Here's the reason: Everyone accepts Provider1's announcement of the block.
> ++> When your link to P1 is up, any traffic they recieve for your prefix
> ++> gets routed over that link since they carry your more-specific internally.
> ++> However, if other providers here the more-specific from P2, they'll
> ++> send directly via P2 who sends it over the link to you.

	But if your chunk of space is greater than /20, the other providers
will filter P2's announcement of your space and you are back to square one.
	Well, at least you won't be cut off from the entire Internet, I guess
that's something. Square 1.5.