Re: [Lsr] New Version Notification for draft-wang-lsr-prefix-unreachable-annoucement-03.txt

Robert Raszuk <robert@raszuk.net> Thu, 30 July 2020 14:30 UTC

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From: Robert Raszuk <robert@raszuk.net>
Date: Thu, 30 Jul 2020 16:30:27 +0200
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To: Peter Psenak <ppsenak@cisco.com>
Cc: Huzhibo <huzhibo@huawei.com>, Aijun Wang <wangaj3@chinatelecom.cn>, lsr <lsr@ietf.org>, Aijun Wang <wangaijun@tsinghua.org.cn>, Xiaoyaqun <xiaoyaqun@huawei.com>
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Subject: Re: [Lsr] New Version Notification for draft-wang-lsr-prefix-unreachable-annoucement-03.txt
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Hey Peter,

Not sure how smart you really want to be here but keep in mind that BGP say
option C may never hear about it all the way to the egress PE in other
domain or area ... It is almost always incongruent with IGP.

So if the BGP path is installed it will indeed be at risk to resolve via
less specific when it is still active BGP path and you too quickly remove
info about unreachability.

Thx
R.

On Thu, Jul 30, 2020 at 4:21 PM Peter Psenak <ppsenak@cisco.com> wrote:

> On 30/07/2020 16:14, Robert Raszuk wrote:
> >      > 2:For bgp example,when the pe node down,the bgp peer must down
> >     within
> >      > 30 mintus,It will not get it up via cancle advertise pua.
> >
> >     for the above it is sufficient to advertise the unreachability for
> few
> >     seconds from each ABR independently. That would be a much more solid
> >     proposal.
> >
> >
> > Not sure about "few seconds" ... IBGP def hold time in number of
> > implementations is 180 sec :) .. but few minutes will work for sure.
>
> depends how you use it.
>
> If you can use the unreachable info in a smart way, it's sufficient if
> it is present for a very short time interval.
>
> thanks,
> Peter
>
> >
> > Thx,
> > R.
> >
>
>