Re: [OSPF] Advertising S-BFD discriminators in OSPF

Manav Bhatia <manavbhatia@gmail.com> Fri, 26 September 2014 01:27 UTC

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Date: Fri, 26 Sep 2014 06:57:26 +0530
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From: Manav Bhatia <manavbhatia@gmail.com>
To: Michael Barnes <mjbarnes@cisco.com>
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Cc: OSPF - OSPF WG List <ospf@ietf.org>
Subject: Re: [OSPF] Advertising S-BFD discriminators in OSPF
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Hi Michael,

Very interesting.

I think there is a disconnect because of our interpretation of what an
RI LSA is envisioned to carry. I assume its meant to advertise
"optional router capabilities" while you believe its to be used solely
for advertising "optional OSPF router capabilities". IMO, limiting the
scope of RI to just OSPF is like using a humvee with all its bells and
whistles to distribute balloons to the children in your friendly
neighborhood park! We wanted a mechanism wherein each router could
proudly tell the world that it was an S-BFD capable node and along
with it also advertise the unique discriminator that the others would
use to reach it. RI we felt, was the perfect tool that we could use
for this purpose.

And btw we're not the first ones to use RI for advertising a router
capability that isnt pertinent to OSPF per se (RFC 5088).

Cheers, Manav

On Fri, Sep 26, 2014 at 12:47 AM, Michael Barnes <mjbarnes@cisco.com> wrote:
> Hi Manav,
>
> Perhaps I missed some earlier discussion, on why you decided to add the
> S-BFD Discriminator TLV to the RI LSA, but I would prefer it not be in that
> LSA. I would like to leave the RI LSA with only information pertinent to
> OSPF rather than pollute it with information for which OSPF has no interest.
> If you're concerned with a trend of creating a new Opaque type for every
> application which might want OSPF to carry information for it, then I would
> suggest we create a generic Application Information LSA.
>
> Regards,
> Michael
>
>
> On 05/30/2014 01:47 AM, Manav Bhatia wrote:
>>
>> Hi,
>>
>> We had submitted the following draft a couple of weeks ago.
>>
>> http://tools.ietf.org/id/draft-bhatia-ospf-sbfd-discriminator-00.txt
>>
>> This draft introduces a new OSPF RI TLV that allows OSPF routers to
>> flood the S-BFD discriminator values in the routing domain.
>>
>> S-BFD is a new charter item (will be approved very soon) in the BFD WG.
>>
>> Would appreciate comments on this.
>>
>> Cheers, Manav
>>
>>
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>