North American Network Operators Group

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  • From: Tony Barber
  • Date: Sat Apr 26 17:51:05 1997

Avi Freedman wrote:
>And ASN 7007 
>We saw about 60k routes in our core routers at the time, and saw
>thousands of routes from 7007 when we looked more carefully.
>We kept clearing sessions to filter 7007 but the routes kept popping
>back up:  Sprint (of course), UUNET, and MCI all had them.
>Also, we had to advertise some of our customers more specifically because
>the dampened 7007 routes (because everyone else was clearing at the time)
>were screwing their connectivity.  I know that some others did this,
>so tomorrow the tables will have a bunch of more specifics, I suppose.
>A note:
>If all more specific routes for a destination are dampened, exsting more 
>general routes will not be looked at.  If this behavior was changed,
>some of the blackholing that went on today would not have been possible.
>But this is a separate topic for discussion.
>I suppose that the immediate topic will be route filtering vs. 
>AS_PATH filtering...

One other :-)
This is one instance where dampening more heavily on longer prefixes paid off
since after all these flaps the more specifics were being 'dampened' for much 
longer than the larger blocks and hence they bounced back with very little 

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