Question about mismatch of origin ASN in parent and more specific route object

Wed Sep 18 22:55:44 UTC 2019

> On Sep 18, 2019, at 6:34 PM, Anurag Bhatia <me at anuragbhatia.com> wrote:
> 
> Hello everyone
> 
> 
> Trying to understand the case from operators here who generate IRR based filters.
> 
> 
> 
> Say if a given example: 
> 
> AS X originating 2001:DB8::/32 with IRR route object having AS X in the origin
> AS X originating 2001:DB8::/48 with IRR route object having AS Y in the origin
> 
> 
> Now for folks who are generating filters, will your tools filter 2001:DB8::/48 because there's a more specific IRR route object which says AS Y while prefix is coming from AS X? 
> Or since generation is based on ASNs (as known directly or resolved via AS SETs) your tools will just generate filter for AS X allowing 2001:DB8::/32 (upto say /48) and won't really for mismatching route object for 2001:DB8::/48? 
>   

Generally you might build the filters one of two ways:

1) with just the ASN, eg: 267 where you would build just with that origin ASN.
2) with the AS-SET, eg: AS-NETHER

This includes 2 ASNs (but could also include other things, eg: AS-AKAMAI) and those are also expanded.

- Jared