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

Randy Presuhn <> Wed, 15 November 2017 19:07 UTC

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From: Randy Presuhn <>
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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.