North American Network Operators Group
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Re: 2001:590::/32 announced by both AS4436 (nLayer) and AS4474 (Global Village, no contact in whois, but seems to be nLayer...)

  • From: Joe Abley
  • Date: Tue Mar 16 13:00:41 2004 
On 16 Mar 2004, at 12:03, bill wrote:


 there is no problem with a prefix being
 announced by more than one ASN.
I am fairly sure that I have seen real-life issues with at least one vendor's BGP implementation which led a valid route object with one origin to be masked by another valid route object with a different origin which was learnt earlier, a masking effect that continued even after the original masking route was withdrawn.

I don't have any solid documentation or results of experiments to support this, although it seemed very real at the time. It has always led me to promote the conservative practice of advertising routes with a consistent origin AS.

Bill: have you done any measurement exercises to determine whether this is, in fact, an issue? Or was your comment above based on the protocol, rather than deployed implementations of the protocol?


Joe