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

Nick Hilliard <> Mon, 24 April 2017 19:59 UTC

Return-Path: <>
Received: from localhost (localhost []) by (Postfix) with ESMTP id F0599129502 for <>; Mon, 24 Apr 2017 12:59:18 -0700 (PDT)
X-Virus-Scanned: amavisd-new at
X-Spam-Flag: NO
X-Spam-Score: -4.201
X-Spam-Status: No, score=-4.201 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, RCVD_IN_DNSWL_MED=-2.3, SPF_PASS=-0.001] autolearn=ham autolearn_force=no
Received: from ([]) by localhost ( []) (amavisd-new, port 10024) with ESMTP id jOGSkIQW38it for <>; Mon, 24 Apr 2017 12:59:17 -0700 (PDT)
Received: from ( [IPv6:2a03:8900:0:100::5]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by (Postfix) with ESMTPS id DA8A6129442 for <>; Mon, 24 Apr 2017 12:59:16 -0700 (PDT)
Received: from crumpet.local ( [] (may be forged)) (authenticated bits=0) by (8.15.2/8.15.2) with ESMTPSA id v3OJx7oG033347 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-SHA bits=256 verify=NO); Mon, 24 Apr 2017 20:59:07 +0100 (IST) (envelope-from
X-Authentication-Warning: Host [] (may be forged) claimed to be crumpet.local
Message-ID: <>
Date: Mon, 24 Apr 2017 20:59:06 +0100
From: Nick Hilliard <>
User-Agent: Postbox 5.0.12 (Macintosh/20170323)
MIME-Version: 1.0
To: Enke Chen <>
CC: Mikael Abrahamsson <>, "" <>
References: <> <> <> <> <> <> <> <23283_1492759950_58F9B58E_23283_375_1_53C29892C857584299CBF5D05346208A31CC352B@OPEXCLILM21.corporate.adroot.infra.ftgroup> <20170421084638.l6pbvtznfsxnq2wy@Vurt.local> <23291_1492766305_58F9CE61_23291_9725_1_53C29892C857584299CBF5D05346208A31CC399E@OPEXCLILM21.corporate.adroot.infra.ftgroup> <20170421095839.sralcy7aos5mzzic@Vurt.local> <> <> <> <> <>
In-Reply-To: <>
X-Enigmail-Version: 1.2.3
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: 7bit
Archived-At: <>
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
X-Mailman-Version: 2.1.22
Precedence: list
List-Id: Inter-Domain Routing <>
List-Unsubscribe: <>, <>
List-Archive: <>
List-Post: <>
List-Help: <>
List-Subscribe: <>, <>
X-List-Received-Date: Mon, 24 Apr 2017 19:59:19 -0000

Enke Chen wrote:
> The CLI migration falls apart when a customer skips releases and jumps
> from one release ("permit all") to another ("deny all").


config downgrading is why the "downward-compatible-config" IOS
configuration command exists.  Config upgrading is relatively
straightforward, although it takes years to implement.

Changing defaults and commands is something which has happened on many
occasions over the lifetime of IOS, from radical config breaking "ip
classless", or my personal favourite, "mop enabled" in the interface
config mode, which changed default backwards and forwards on several
occasions, not just once (I'd love to hear the back-story about how and
why that happened, btw).  Other well known examples include the modular
QoS config mechanism which removed the older qos config mechanisms.

Just because a large vendor doesn't like changing defaults, that doesn't
mean it's not a sensible thing to standardise.

No-one is under any illusion that there is a cost to vendors
implementing this but right now, the cost of not doing it is borne by
other people, and we're tired of it.