[routing-wg] does HE's BGP toolkit only show actually seen announcements? (was: is RIPEstat confused about the origin of 147.171.0.0/16?)

Hi Martin,

(related to a recent discussion on RIPE routing-wg ML [0]) 

I was wondering whether HE's bgp toolkit displays announced prefixes only
or 
announced prefixes _AND_ prefix-origin pairs for which ROAs exits.

Example: 186.182.0.0/16
announced according to RIS by one ASN: AS19037 [2] (invalid per RPKI)
bgp.he.net [1] shows two announcements (one valid, one invalid)
rt-bgp [3] shows one orign ASN (AS19037)  (invalid)

The question is: Are both announcements visible to HE (HE just sees more announcements than RIS) 
or is the second entry just the display of a ROA (that is not actually announced)?

thanks,
nusenu

[0] https://www.ripe.net/ripe/mail/archives/routing-wg/2018-September/003630.html
[1] https://bgp.he.net/net/186.182.0.0/16
[2] https://stat.ripe.net/widget/looking-glass#w.resource=186.182.0.0%2F16
[3] https://rt-bgp.he.net/prefix/186.182.0.0/16

Alex Band:
> Hi nusenu,
> 
> Please note that the RPKI Validator BGP Preview only shows
> announcements that are “widely seen”, which in this case 5 peers or
> more. Anything lower than that will not simply show up in the list,
> however it may still be listed in the dump file Rene linked to.


> 
> Cheers,
> 
> —Alex
> 
>> On 27 Sep 2018, at 03:07, Rene Wilhelm <wilhelm at ripe.net> wrote:
>> 
>> Hi,
>> 
>> On 9/27/18 1:11 AM, nusenu wrote:
>>> Hi, I came across this particular prefix when going through big
>>> RPKI unreachable blocks. prefix-routing-consistency [1] says:
>>> current origin is AS2200 prefix-overview [2] says: current origin
>>> is AS1942  (nlnog's LG agrees) routing-history [3] says it was
>>> announced by AS220 until 2017-06-10 and is currently announced by
>>> AS1942 RPKI validator's BGP Preview (using RIS): says it is
>>> announced by AS1942 and is therefore invalid (ROA authorizes
>>> AS2200 - not AS1942) So why does [1] say this prefix is announced
>>> by AS2200? maybe it is announced by both?
>> 
>> 
>> I do not know what is announced, but RIS observes the prefix with
>> both origins. As the looking-glass widget states:
>> 
>> "19 RRCs see 202 peers announcing 147.171.0.0/16 originated by 2
>> ASNs"
>> 
>> https://stat.ripe.net/widget/looking-glass#w.resource=147.171.0.0%2F16
>>
>>
>> 
Actually, it is just one single peer on collector rrc04 (Geneva) which sees AS2200 as origin; that's why prefix-overview and routing-history
>> do not show the info by default. You have to deselect 'Exclude low 
>> visibiliy' (prefix-overview) and 'No low visibility'
>> (routing-history) options in the widgets to see it.
>> 
>> RPKI validator's BGP Preview might be using similar logic. The
>> latest RIS dump, http://ris.ripe.net/dumps/riswhoisdump.IPv4.gz 
>> lists 147.171.0.0/16 with both AS1942 (203 peers) and AS2200 (1
>> peer) as origin.
>> 
>> prefix-routing-consistency widget appears to indeed have problems; 
>> at least in this case. It only shows a result for the route
>> observed by the lowest amount of peers.
>> 
>> 
>> -- Rene
>> 
>> 
>> 
>> 
>> 
>>> btw: AS2200 and AS1942 have the same owner and AS2200 appears to
>>> be the only upstream of AS1942. [1]
>>> https://stat.ripe.net/widget/prefix-routing-consistency#w.resource=147.171.0.0%2F16
>>>
>>> 
[2] https://stat.ripe.net/widget/prefix-overview#w.resource=147.171.0.0%2F16
>>> [3]
>>> https://stat.ripe.net/widget/routing-history#w.resource=147.171.0.0%2F16
>
>>> 
> 

-- 
https://twitter.com/nusenu_
https://mastodon.social/@nusenu

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