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Re: Link up wait timeout [was: Bug#537271: netcfg: new version of gateway reachability patch]

On Wed, Feb 9, 2011 at 09:57, Matthew Palmer <mpalmer@debian.org> wrote:
> [Taking this off-bug]
> On Wed, Feb 09, 2011 at 02:52:53AM -0500, Robert Edmonds wrote:
>> btw, (unrelated to #537271), it seems to me that 3 seconds is a fairly
>> short value for NETCFG_LINK_WAIT_TIME.  i'm pretty sure i've seen
>> link-up take longer than that on occasion before, depending on NIC
>> chipset, switch, autonegotiation latency, etc.
> I've been led to believe by people who should know (a Linux netdev
> maintainer) that autonegotiation *should* take on the order of 500ms.
>> 5 - 10 seconds would be
>> a more conservative default, given that there's no penalty if link-up
>> occurs before the timeout.
> Sure, there's no penalty is link-up occurs, but what about all the people
> for whom link-up doesn't occur -- say, because they're on a wireless link,
> or their chipset doesn't work right, or it's trying on a link that isn't
> actually up?  Every delay screws them over more and more.

It seems we have a trade-off here.

I think the decision depends on the number of affected users:

 - how many will have link-up in less of this time?
 - how many chipset has issues with it and will end up getting it in 5
or 10 secs?
 - could it be !wireless specific?


Otavio Salvador                             O.S. Systems
E-mail: otavio@ossystems.com.br  http://www.ossystems.com.br
Mobile: +55 53 9981-7854              http://projetos.ossystems.com.br

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