Re: [Idr] BGP flooding and AS-PATH

Robert Raszuk <robert@raszuk.net> Mon, 11 March 2019 11:38 UTC

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From: Robert Raszuk <robert@raszuk.net>
Date: Mon, 11 Mar 2019 12:38:13 +0100
Message-ID: <CAOj+MMGZQOosfLus46QB9_h-2YeiDx4T-28=tpK2R7sLSmCHVA@mail.gmail.com>
To: "Ketan Talaulikar (ketant)" <ketant@cisco.com>
Cc: "idr@ietf. org" <idr@ietf.org>
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Archived-At: <https://mailarchive.ietf.org/arch/msg/idr/R1NAN_ujxE5hmtEa2WitmH_iJa8>
Subject: Re: [Idr] BGP flooding and AS-PATH
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Hi Ketan,

I was not talking about TORs .. they will get all info just fine.

I was talking about same stage peers as they can have same AS number and
with eBGP there may be a bit of challenge to get BGP updates accepted
orignated by same level device.

And I was only waiting for you to mention allowas-in or as-overwrite knobs
;)

Can you reflect those options in the draft? Or at least in any other way
address this scenario ?

Kind regards,
R.

On Mon, Mar 11, 2019, 11:41 Ketan Talaulikar (ketant) <ketant@cisco.com>
wrote:

> Hi Robert,
>
>
>
> Please check inline below.
>
>
>
> *From:* Robert Raszuk <robert@raszuk.net>
> *Sent:* 11 March 2019 15:05
> *To:* Ketan Talaulikar (ketant) <ketant@cisco.com>
> *Cc:* idr@ietf. org <idr@ietf.org>
> *Subject:* BGP flooding and AS-PATH
>
>
>
> Dear authors of draft-ketant-idr-bgp-ls-bgp-only-fabric,
>
>
>
> I would like to ask for a small clarification on how in the quoted RFC7938
> design are you going to propagate topology information between peers
> configured with the same AS number ? Say between devices belonging to tier
> 1 stage or to a sets in tier 2 stages ?
>
>
>
> Do you assume that those switches just do not need to be aware of each
> other's presence say for TE purposes ?
>
> *[KT] This isn’t necessary in the use-cases where controller is doing the
> TE computations. E.g. a TOR can delegate end to end TE computation (from
> itself all the way over the DCI/WAN to a remote node) to the controller.*
>
>
>
> Specifically I am curious how are you going to accomplish it in the cases
> where no AS-PATH removing controller is involved as described here:
>
>
>
> "An internal software component on any of the BGP routers
>
> (e.g. TE module) can also receive the entire BGP network
>
> topology information from its local BGP process."
>
> *[KT] This is a different variant of the TE use-case where the TOR itself can do TE computation. In this case, you are correct about the topology flooding via the controller when using the ASN scheme in https://tools.ietf.org/html/rfc7938#section-5.2.1 <https://tools.ietf.org/html/rfc7938#section-5.2.1> . For this use-case, there are other options and designs though (incl private AS for unique assignment to TORs, allowAS-in, etc.) to make this possible.*
>
>
>
> *Thanks,*
>
> *Ketan*
>
>
>
> Thx a lot,
>
> R.
>
>
>

[Idr] BGP flooding and AS-PATH Robert Raszuk
Re: [Idr] BGP flooding and AS-PATH Ketan Talaulikar (ketant)
Re: [Idr] BGP flooding and AS-PATH Robert Raszuk
Re: [Idr] BGP flooding and AS-PATH Ketan Talaulikar (ketant)