[En-Nut-Discussion] Network Link state on at91_emac and others

[Henrik Maier]

Maybe the unplug behaviour is different if DHCP is enabled or not?

With DHCP we are likely to get a new IP address and this prevents the
existing sockets to communicate after link has been restored.

Henrik
 
> -----Original Message-----
> From: en-nut-discussion-bounces at egnite.de [mailto:en-nut-discussion-
> bounces at egnite.de] On Behalf Of Harald Kipp
> Sent: Tuesday, 16 September 2008 6:42 PM
> To: Ethernut User Chat (English)
> Subject: Re: [En-Nut-Discussion] Network Link state on at91_emac and
> others
> 
> Ole Reinhardt wrote:
> 
> > The PC will mostly drop the connection just in the moment of
> > disconnection as most OSes behave like this.
> 
> If this is the case, then "most OSes" are plain wrong.
> 
> We just tried Kubuntu (Kernel 2.6.22) and Windows 2000 SP4:
> 
> 1. Establishing a TELNET connection to our Internet gate.
> 2. Pull the cable at the PC running the TELNET client.
> 3. Reconnecting the cable after a few seconds.
> 
> On both systems the TELNET connection is still alive. If you like we can
> try OS X too, but I'm sure it will behave the same way unless you
> enabled special keepalive options.
> 
> > That's why I don't see having a timeout or even holding the
> > sockets is a good idea.
> 
> I will not getting tired to argue, that TCP is designed to keep
> connections on broken links.
> 
> I will not getting tired to argue, that dropping connections on Ethernet
> link loss will not solve any problem.
> 
> I will not getting tired to argue, that implementing keepalive is the
> only correct way to detect broken links.
> 
> I will not getting tired to argue, that keepalive, if implemented, must
> be disabled by default.
> 
> Harald
> 
> 
> 
> 
> 
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