[j-nsp] BGP timer

Jeff Haas jhaas at juniper.net
Mon Apr 29 08:42:42 EDT 2024


Juniper Business Use Only
On 4/29/24, 02:41, "Saku Ytti" <saku at ytti.fi <mailto:saku at ytti.fi>> wrote:
> On Sun, 28 Apr 2024 at 21:20, Jeff Haas via juniper-nsp
> > BFD holddown is the right feature for this.
>
> But why is this desirable? Why do I want to prioritise stability
> always, instead of prioritising convergence on well-behaved interfaces
> and stability on poorly behaved interfaces?

This feature is "don't bring up BGP on interfaces that aren't stable enough to
let BFD stay up".  The intended use case is when you have an interface noisy
enough that TCP can fight its way through keeping BGP up... enough, but not
stable enough that you'd really want to forward over it.  The assessment for
that is "BFD will go down in short order".

> That is, if I cannot have exponential back-off, I won't kill
> convergence 'just in case', because it's not me who will feel the pain
> of my decisions, it's my customers. Netengs and particularly infosec
> people quite often are unnecessarily conservative in their policies,
> because they don't have skin in the game, they feel the upside, but
> not the downside.

People make decisions that are appropriate for their networks.  Using BFD on
your BGP sessions is probably overkill *for you*.  Don't do that then.

-- Jeff



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