Re: [netmod] Comment on draft-clacla-netmod-yang-model-update-02

Randy Presuhn <randy_presuhn@alumni.stanford.edu> Wed, 15 November 2017 19:07 UTC

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References: <19a4129f-84b4-2d6b-8405-37b85952f53a@ericsson.com> <20171114212210.7b2g3t3nqzrhcgrs@elstar.local> <20171115053046.nr33ypoibdn4jufv@elstar.local> <9094b945-366f-145d-fbc1-5cf116f4a3bc@cisco.com> <614c9b33-774a-cbe0-0328-cfc7ad9ac11b@ericsson.com>
From: Randy Presuhn <randy_presuhn@alumni.stanford.edu>
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Date: Wed, 15 Nov 2017 11:07:27 -0800
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Subject: Re: [netmod] Comment on draft-clacla-netmod-yang-model-update-02
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Hi -

On 11/15/2017 2:02 AM, Balazs Lengyel wrote:
> While a server may correctly support multiple versions, the human 
> operator on the CLI has a 99% chance of mixing up which version he is 
> using. Humans will not check every type and leaf  to check that they 
> remember the little differences between model versions. It is a recipe 
> for human mistakes. According to some statistics 50% of downtime is 
> caused by human errors, so we should not provide the operator with a gun 
> to shoot himself. Ericsson has a rule never to have multiple versions of 
> the same module on a network node.

Does this mean that they require all line cards in a chassis to have
exactly the same firmware revision level?  If so, when a card with a
newer firmware revision level is swapped in, does that require all other
cards of the same type in that chassis to also be replaced concurrently?
Sounds like even a fairly routine/minor update/repair would effectively
result in a system outage.

Randy