Re: Debugging accepted routes from BGP speakers

+1 Jakob

Sometime ago, validating exactly that (across 4 vendors/6 OS's), I observed  difference in behaviors across vendors and in 1 instance between different OS’s of the same vendor

Cheers,
Jeff
On Nov 19, 2019, 1:19 PM +0800, Jakob Heitz (jheitz) <[email protected]>, wrote:
> In https://tools.ietf.org/html/rfc4271#section-9.1.2
> the AS loop is broken at the receiver.
> Nowhere does it say that the sender must break the AS loop.
> Split horizon filtering is a common practice, but nowhere
> is it mandated. At least I could not find it.
>
> If the receiver of your route were to send you back its
> best path, even if it's your route, then you have your
> information.
>
> We could invent an address-family specific capability
> to indicate that you wish your route to be echoed back.
>
> Regards,
> Jakob.
>
> -----Original Message-----
> From: Idr <[email protected]> On Behalf Of Job Snijders
> Sent: Monday, November 18, 2019 3:00 AM
> To: Robert Raszuk <[email protected]>
> Cc: IDR <[email protected]>
> Subject: Re: [Idr] Debugging accepted routes from BGP speakers
>
> On Mon, Nov 18, 2019 at 9:50 AM Robert Raszuk <[email protected]> wrote:
> > > The latter one is oftentimes easily validated by Internet-wide looking glasses
> >
> > Hmmmm I must say that IMHO both latter and former could be addressed by looking-glass. In fact when I read this draft that was my first question - why not to just look at peer's looking glass ?
>
> Many networks unfortunately do not make BGP Looking Glasses available,
> nor is there any standardized interface/method/design/approach for BGP
> Looking Glasses. So solely relying on Looking Glasses for this
> functionality has proven to be insufficient.
>
> > So perhaps we should simply issue a BCP to say that each AS should run a looking glass server holding all paths and declare victory ? And that could be all GROW WG thing too :)
>
> That is an interesting idea, but in my mind not the exclusive viable solution.
>
> > I already see a bunch of new things we could accomplish in the Internet if we would have those in place consistently everywhere - at least for each transit AS.
>
> Agreed - it would be a nicer world. Through the MANRS initiative I've
> pitched the idea to provide more encouragement for networks to provide
> looking glasses to the public, but arguably their availability is not
> ubiquitous.
>
> Another observation is that in the "IP Transit Carrier" segment of the
> market we see BGP Looking Glasses from time to time, but we rarely see
> similar functionality offered by Cloud/CDN providers. Perhaps the
> latter category is not interested in running & maintaining looking
> glasses, or perhaps there are other constraints that prevent them from
> exposing this information via suchs tools. My hope is that by creating
> a feedback mechanism in BGP we create more opportunity to share
> debugging information specific to EBGP sessions between different
> orgs.
>
> Kind regards,
>
> Job
>
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