Re: [Idr] IETF LC for IDR-ish document <draft-ietf-grow-bgp-reject-05.txt> (Default EBGP Route Propagation Behavior Without Policies) to Proposed Standard

Enke Chen <enkechen@cisco.com> Thu, 20 April 2017 15:57 UTC

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To: Job Snijders <job@ntt.net>
References: <D4E812E8-AA7B-4EA2-A0AC-034AA8922306@juniper.net> <abe393d3-d1e4-7841-4620-38dab751765b@cisco.com> <68B29403-9AD9-4F06-9FE4-3F077E793D9F@puck.nether.net> <275cf744-1f64-bcbc-dabe-a47479921230@cisco.com> <20170420154142.lacvtplusepy3qcf@hanna.meerval.net>
Cc: Jared Mauch <jared@puck.nether.net>, Hares Susan <shares@ndzh.com>, idr@ietf.org, Enke Chen <enkechen@cisco.com>
From: Enke Chen <enkechen@cisco.com>
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Date: Thu, 20 Apr 2017 08:57:07 -0700
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Archived-At: <https://mailarchive.ietf.org/arch/msg/idr/J1G9JNm0P2rbb-qCqJ_u1bLqKLE>
Subject: Re: [Idr] IETF LC for IDR-ish document <draft-ietf-grow-bgp-reject-05.txt> (Default EBGP Route Propagation Behavior Without Policies) to Proposed Standard
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Job,

It depends on the customer base and also how long the software has been deployed.
Just think about the scenario that a large number of customers would lose network
connectivity unexpectedly due to a default behavior change in the code. Such outages
could keep happening to different customers for years to come.

Perhaps, changing "impossible" to "impractical" :-)

Regards,  -- Enke

On 4/20/17 8:41 AM, Job Snijders wrote:
> On Thu, Apr 20, 2017 at 08:36:17AM -0700, Enke Chen wrote:
>> If it is not obvious, let me state the I participate in IDR WG as an
>> individual contributor, just like you do I suppose.
>>
>> Let me rephrase what I said, for a code base with a large and diverse
>> customer base I do not foresee any possibility for the default
>> behavior change in this case. Again please treat it as my personal
>> opinion.
>>
>> I am certainly aware of other cases where the default behavior has
>> been changed. But this one is different.  This case seems similar to
>> the default behavior ("permit" or "deny") for an empty ACL.  Once the
>> "permit" or "deny" is set in the code and is widely deployed for a
>> long time, it is just not possible to make the switch between "permit"
>> and "deny".
> 
> You say "it is not possible", however there are examples where it turned
> out to be possible. At least one implementer confirmed on this list that
> they plan to change their default.
> 
> Perhaps, "impossible" should be phrased as "unwilling".
> 
> Kind regards,
> 
> Job
>