North American Network Operators Group

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RE: Confussion over multi-homing

  • From: Paul Froutan
  • Date: Thu Sep 14 17:13:21 2000

At 9/14/00 -0400, Richard Welty wrote:

> Wouldn't one of the ISPs have to advertise a longer prefix?

actually, to do it right, both have to advertise the longer prefix --
or more specifically, they have to both make holes in their filters
permitting the multi-homed site to advertise them.

this is what we're doing in our Troy, NY facility -- we have 2
and we have a /24 from one of them, which both of them pass through.
What you can do is get permission from the ISP that provides you the IPs (say ISP A) so you can have other ISPs announce your blocks. You also need to get ISP A to deaggregate your block and announce it separately into the global BGP table. We did this back in the day and it works fine if the ISP giving you IPs is somewhat reasonable and helpful.

Paul Froutan Email: [email protected]
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