Re: [Idr] New BGP capability to advertise running daemon version

Jeffrey Haas <jhaas@pfrc.org> Fri, 23 August 2019 15:25 UTC

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Date: Fri, 23 Aug 2019 11:27:59 -0400
From: Jeffrey Haas <jhaas@pfrc.org>
To: John Scudder <jgs@juniper.net>
Cc: Job Snijders <job@ntt.net>, "idr@ietf. org" <idr@ietf.org>
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Subject: Re: [Idr] New BGP capability to advertise running daemon version
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On Fri, Aug 02, 2019 at 05:35:40PM +0000, John Scudder wrote:
> On Aug 2, 2019, at 11:02 AM, Jeffrey Haas <jhaas@pfrc.org<mailto:jhaas@pfrc.org>> wrote:
> > If I could be talked into wanting this at all, I suspect I might be more
> > supportive of having this be an optional parameter rather than a capability.
> 
> The problem with that suggestion is that the defined behavior for receiving an optional parameter you don’t recognize is to reset the session. I presume you would not suggest that it’s desirable for an unrecognized version string to cause a session to not come up. Years ago we did recognize this issue and introduced a way to send parameters that if unrecognized are just ignored instead of causing a reset. We called those parameters “capabilities”. :-/

Just to close the thread here, I agree with your argument and withdraw my
suggestion.  "Optional" is perhaps not the best name for the 4271 feature at
this point given its resistance to using it for future extensions.

It does leave me feeling like it may be easier to just rename capabilities
as "BGP Open TLVs" and be done with it. :-)

-- Jeff (maybe for BGP-5)